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Body of Knowledge Module 14
Airport Operations And Federal Aviation Regulation
Part 139—Certification
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These modules were originally written by Stephen Quilty, A.A.E., and have been updated
by the AAAE BOE, AAAE staff, and industry experts.
2004/2005
@All Rights Reserved
American Association of Airport Executives
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ContentsModule Objectives ................................................................................................ 1
Airport Certification ............................................................................................. 2
FAR Part 139 .................................................................................................. 2
Airport Certification Manual .................................................................. 3
Requirements and Contents of an ACM ..................................................4Airport Self-Inspection ................................................................................... 7
Pavement Surfaces .......................................................................................... 8
Pavement Condition and Inspection ........................................................9
Pavement Skid-Resistance .....................................................................11
Pavement Friction Measurement ...........................................................13
Movement and Safety Areas.........................................................................14
Markings, Signs and Lighting ......................................................................15
Airfield Lighting .................................................................................... 16
Airfield Signs ......................................................................................... 17
Airfield Markings ..................................................................................19
Snow and Ice Control.............................................................................23Snow and Ice Plan ........................................................................................ 24
De-ice and Anti-ice Compounds............................................................25
Aircraft De-icing .................................................................................... 26
Snow Removal Equipment ...........................................................................28
Rotary Snowblowers..................................................................................... 28
Snow Plows ............................................................................................ 28
Sweepers ................................................................................................ 29
Material Spreaders ........................................................................................ 30
Snow and Ice Removal Techniques ....................................................... 30
Airport Condition Reporting ........................................................................32Notices to Airman (NOTAM). ...............................................................32
Airport Construction Activity ................................................................34
Pedestrians and Ground Vehicles .................................................................35
Public Protection .......................................................................................... 35
Wildlife Hazard Management.......................................................................36
Summary.......................................................................................................40
Study Questions ............................................................................................ 43
TablesTable A: Subpart D-Operations .............................................................................................. 5
Table B: Runway Marking Elements ................................................................................... 19
Figures
Figure 1: Signing Examples for a Complex Airport ............................................... 18
Figure 2: Runway Markings ................................................................................... 20
Figure 3: Special Runway Markings ....................................................................... 20
Appendix A: Standard for Airport Sign System ......................................................................... 41
Appendix B: ACM Elements - Section 139.203 (B) .................................................................. 42
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Module Objectives
Can you....
1. identify the certification requirements as stipulated in FAR Part 139?
2. distinguish the four classes of airports as defined by the most recent FAR Part 139?
3 explain what purpose an airport certification manual (ACM)serves, what it
should provide, and what it should emphasize?
4. identify the key components of an airport safety self-inspection program and the
types of activities they address?
5. identify those factors that affect pavement strength and wear and how to
mitigate deterioration?
6. explain the effects of poor pavement conditions on aircraft and how pave-
ment traction and friction can be maintained and improved?
7. explain how pavement conditions are measured and the effect of different
readings?
8. delineate the movement and safety areas of an airport and the criteria that
affects them?
9. identify the different types of approach lighting systems that exist and their
operating criteria?
10. identify the marking and signage requirements at airports and delineate their
inscriptions or color?
11. describe the effects of snow and ice on pavement surfaces and the responsibility
of airport operations to mitigate their effects?
12. explain the purpose of snow and ice plans and their basic components?
13. explain the various methods and timing for removing snow and ice from
pavement surfaces?
14. describe the basic properties of anti-ice and de-ice compounds?
15. identify when and what information is conveyed in a NOTAM?
16. determine when to conduct a Wildlife Hazard Assessment at an airport and
strategies for resolving or mitigating wildlife hazards?
17. explain the acronyms, terms, and common phrases used in the module?
18. interpret and explain the basic concepts presented in the various tables?
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Airport Certification
The heart and soul of any airport organization is Airport Operations. The opera-
tions departments of most airports were created following the promulgation of
federal airport certification in the early 1970’s. Prior to this regulation, airport
maintenance departments generally performed airfield inspections and then
repaired any deficiencies found. The formal certification program now requiresthe operating departments to keep the airport functioning safely and efficiently.
These responsibilities include daily inspections; reporting of problems; inform-
ing tenants, users, and staff of current conditions; monitoring corrections and the
coordination of overall activities.
The Federal Aviation Administration (FAA) has the statutory authority, originally
approved by Congress in the Airport and Airways Development of 1970, to issue
Airport Operating Certificates (AOCs) to airports serving certain air carriers and
to establish minimum airport safety standards. This authority has been codified
in the Code of Federal Regulations as Part 139, Certification of Airports.
Under the most recent revision to FAR Part 139, airports that are served by
scheduled air carrier aircraft designed for more than 9 passenger seats or airports
serving unscheduled air carrier aircraft designed for at least 31 passenger seats
are subject to certification and annual safety inspection. All federally certified
airports are required to be operated and maintained in a safe and serviceable
condition in accordance with minimum standards required or prescribed in Part
139. The purpose of these inspections is to determine compliance with regulatory
safety standards.
FAR Part 139
In 2004, the FAA, as directed by Congress in the Aviation Investment and Re-
form Act for the 21st century (Air 21-Public Law 106-181), issued revised rules
for the certification of airports. The new regulations expanded and clarified
existing requirements by reclassifying airports into four categories according to
the type of air carrier operations.
The term air carrier aircraft was redefined to include large air carrier aircraft and
small air carrier aircraft. An aircraft that is being used by an air carrier is catego-rized as large if it is designed for at least 31 passenger seats and small if de-
signed for more than 9 seats but fewer than 31 seats.
The four classes of airports defined by Part 139 are as follows:
Class I is an airport certificated to serve scheduled operations of large air
carrier aircraft. It can also serve unscheduled passenger operations of large
air carrier aircraft and/or scheduled operations of small air carrier aircraft.
Objective 1
Airports that are served by scheduled air carrier
aircraft designed for
more than 9 passenger
seats or airports serving
unscheduled air carrier
aircraft designed for at
least 31 passenger seats
are subject to certifica-
tion and annual safety
inspection.
The new FAA regula-
tions expanded and
clarified existing
requirements by
reclassifying airports
into four categories
according to the type of
air carrier operations.
Air carrier aircraft was
redefined to include
large air carrier aircraft
(designed for at least31 passenger seats) and
small air carrier aircraft
(designed for more
than 9 seats but fewer
than 31 seats).
Objective 2
2
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ACM —Airport
Certification Manual
Objective 3
Class II is an airport certificated to serve scheduled operations of small air
carrier aircraft and the unscheduled passenger operations of large air carrier
aircraft. This class may not serve scheduled large air carrier aircraft.
Class III is an airport certificated to serve scheduled operations of small air
carrier aircraft. This class may not serve scheduled or unscheduled large air
carrier aircraft.
Class IV is an airport certificated to serve unscheduled passenger opera-
tions of large air carrier aircraft. This class may not serve scheduled large
or small air carrier aircraft.
An air carrier operation is a takeoff or landing of an air carrier aircraft. It
includes the period of time from 15 minutes before until 15 minutes after
the takeoff or landing.
All airports in each class that are certificated under Part 139 must prepare
and operate under an Airport Certification Manual (ACM) approved by theFAA. The ACM is structured to help an airport comply with the statutory
requirements. The intent of the ACM is to provide necessary information to
personnel who are responsible for operating the airport or who are affected
by the regulations.
Air carriers are specifically precluded from using an airport for operations
that is not Part 139-certificated, and an airport is required to have an Air-
port Operating Certificate in order to accommodate air carrier activity.
Exceptions to the rule that may allow the use of a noncertificated airport
involve cases of an aircraft emergency, training flights, or an airport ap-
proved as an air carrier alternate.
Airport Certification Manual
Because Part 139 is written in broad terms to accommodate all airports cov-
ered by the regulation, it does not define how an airport is to be operated. It is
the ACM that functions as an extension of the Federal Regulations and pro-
vides the bridge between the general requirements of Part 139 and the applica-
tion at each airport, taking into account the airport’s specific site, activity, and
configuration. By requiring an airport to develop an ACM, the FAA places the
burden and responsibility for compliance on the airport operator. The FAAthen administers Part 139 by enforcing the contents of the approved ACM.
The ACM should provide enough direction to achieve compliance with the
regulation but not be so detailed as to lack operational flexibility or result in
constant violation of the manual. It is suggested that airport management’s
approach be comprehensive yet conservative. Only details necessary to show
how regulatory compliance is to be achieved is required. A good path for airport
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management to take is to write the ACM as though they are leaving instructions
for someone to carry out.
When developing, writing, or revising the ACM, emphasis is placed on estab-
lishing responsibility, authority, and procedures for Part 139 compliance. This
is accomplished by identifying who is going to perform the tasks, what the
tasks will be, how the tasks are to be performed, and when they will be accom-
plished. Beyond that, excessive levels of detail can restrict the flexibility of
airport personnel to meet unforeseen circumstances, or even create unnecessary
commitments under the regulation. This is because, upon approval, the ACM
becomes a document with considerable legal significance.
Part 139 requires airport management to furnish all applicable portions of the
airport’s ACM to those airport personnel responsible for its implementation. It
is not intended that the ACM provide complete instructions on how to do a job.
If the ACM is well prepared and followed, it will result in job performance that
maintains the airport in regulatory compliance.
Requirements and Contents of an ACM
As a working document that reflects an airport’s current condition and opera-
tion, changes to the certification manual or specifications are to be expected.
Part 139 requires that the ACM be typewritten or printed, but it is not specific
on the form or material. However, it should be in a format that is easy to revise.
The ACM is normally bound in a loose-leaf, standard size, three-ring binder so
it can be easily organized and maintained. The FAA requires that each page
show the approval date, either as part of the original document or as a revision
or addition.
Either the certificate holder or the FAA through the Regional Airports Division
Manager may initiate an amendment to the ACM. Amendments to the ACM
should be submitted to the FAA 30 days before their effective date.
An airport may petition the FAA for an exemption from any Part 139
requirement. A request for an exemption becomes a rulemaking action and
requires the submittal of information demonstrating that compliance with
the requirement would be unreasonably costly, burdensome, or impractical.
If approved, an exemption issued to an airport effectively changes the
manner in which the airport complies with its operating certificate.
On occasion, an airport may be faced with a situation that could result in a
deviation from the regulations. Whether the deviation results in an actual
violation depends on the circumstances involved. Under Part 139, any
deviation requires that airport management inform the FAA not later than
14 days of the occurrence. Deviations are permitted in circumstances that
primarily emanate from an aircraft emergency. For example, if as the result
of an onboard safety problem, an air carrier used a runway that did not meet
What to emphasize
when developing,
writing, and revising
ACM—establish
responsibility,
authority, and proce-dures for Part 139
compliance
Amendments to theACM — must be
submitted 30 days
before the effective
date.
Under Part 139, an
airport manager must
inform the FAA of a
deviation from
regulations not later
than 14 days of the
occurrence.
An example of
violation of regula-
tions—Allowing air
carrier operations
while the airport’s
firefighting equipment
is participating in an
off-airport training
exercise.
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the safety requirements of the ACM. This type of deviation from a regula-
tion may be acceptable because of the emergency circumstances. However,
the allowing of air carrier operations while the airport’s firefighting equip-
ment is participating in an off-airport training exercise is not a deviation,
but a violation.
A few sections of Part 139 demand actions beyond the authority of the airport
operator. Qualifying language such as “to the extent practicable” or “which
agrees to provide” highlights these sections and targets an attempt to achieve the
desired result. Examples are obstruction lights outside airport boundaries or
medical assistance and transportation from community resources.
Each airport, in accordance with its specific classification, must include in its
ACM a description of the operating procedures, facilities and equipment, re-
sponsibility assignments and other related information needed by key personnel
to comply with the applicable provisions of Subpart D—Operations. Table A
lists the major elements included in Subpart D.
The regulations also describe the specific manual elements for each class of
airports. See Appendix B.
Each airport, in accor-
dance with its specific
classification, must
include in its ACM a
description of the
operating procedures,
facilities and equipmen
responsibility assign-
ments and other relate
information needed by
key personnel to compl
with the applicable
provisions of Subpart
Table A: Subpart D—Operations
Section 139.301 Records.
Section 139.303 Personnel.
Section 139.305 Paved Areas.
Section 139.307 Unpaved Areas.
Section 139.309 Safety Areas.
Section 139.311 Marking, signs and lighting.Section 139.313 Snow and ice control
Section 139.315 ARFF: Index determination.
Section 139.317 ARFF: Equipment and agents.
Section 139.319 ARFF: Operational requirements.
Section 139.321 Handling and storing of hazardous substances and materials.
Section 139.323 Traffic and wind direction indicators.
Section 139.325 Airport emergency plan.
Section 139.327 Self-inspection program.
Section 139.329 Pedestrians and Ground Vehicles.
Section 139.331 Obstructions.
Section 139.333 Protection of Navaids.
Section 139.335 Public Protection.Section 139.337 Wildlife hazard management.
Section 139.339 Airport condition reporting.
Section 139.341 Identifying, marking and lighting construction and other unserviceable areas.
Section 139.343 Noncomplying conditions.
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The FAA Airport Certification Branch annually inspects all Part 139 airports.
However, FAR Part 139 authorizes FAA to inspect at any time.
The FAA requires airports to employ sufficiently qualified personnel to operate the
airport in a safe manner. This regulation is met if all the requirements in the ACM are
properly performed. Those individuals who are authorized to carry out the responsi-
bilities of ACM compliance are specifically identified, and they are required to be
well trained and educated in the requirements. Training records for operating and
emergency personnel must be kept for twenty-four consecutive calendar months.
The section on paved areas includes several specific requirements for surfaces
available only for air carrier use. Outside of Alaska a section on unpaved areas is
not frequently found in an ACM. Safety areas were redefined to include runway
or taxiway areas and the surrounding surfaces that are prepared or suitable for
reducing the risk of damage to an aircraft in the event of an undershoot, over-
shoot, or excursion from a runway or unintentional departure from a taxiway.
Because different criteria exist for the type of aircraft landing approaches to anairport, the section on marking, signs, and lighting reflects the requirements for
runways and taxiways to fulfill the criteria. Weather conditions may also affect
safe air carrier operations, and therefore snow and ice control is addressed.
Three sections under Part 139 address the airport’s responsibilities for aircraft
rescue and firefighting (ARFF). The sections detail the level of ARFF response
necessary, the type of equipment and agents appropriate, and the performance
requirements for ARFF response.
The handling and storage of hazardous substances and materials are also covered.
Hazardous materials include two different situations found at airports—oneconcerns hazardous materials such as aircraft cargo, and the other concerns
hazardous materials in the form of fuels that are for the operation of the aircraft
and are not considered cargo.
Part 139 airports are required to have traffic and wind direction indicators that
assist a pilot in determining safe conditions for landing or taking off.
In the event of emergencies, certificated airports must have a detailed emergency
plan to respond to the situation. The section on Airport Emergency Plans (AEP)
contains technical information that helps airport management develop an AEP.An AEP addresses several different conditions besides an aircraft emergency.
The section on an airport’s self-inspection program is very important because it
affects so many other areas of Part 139 compliance. It identifies what needs to be
monitored in order to be in compliance with the regulations.
The safety requirements for ground vehicles operating on the airfield and termi-
nal areas and the responsibilities of airport management to monitor obstructions
that fall within the airport’s authority must be described within the ACM. A
The safety area
section refers to
requirements for the
areas of and immedi-
ately surrounding the
runway and taxiway
surfaces.
Three sections under Part 139 address the
airport’s responsibili-
ties for aircraft rescue
and firefighting
(ARFF): (1) the level
of ARFF response
necessary, (2) the type
of equipment and
agents appropriate,
and (3) the perfor-
mance requirements
for ARFF response.
ARFF—aircraft
rescue and firefighting
6
Part 139 certificated
airports are required to
have traffic and wind
direction indicators
that assist a pilot in
determining safe
conditions for landingor taking off.
AEP—Airport
Emergency Plan
addresses several
different conditions
besides an aircraft
emergency.
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separate section covers the requirement to protect navaids from electrical inter-
ruption, signal interference, and vandalism. Partly for these reasons, the FAA
stipulates that airports prevent inadvertent entry into an area containing hazards
for the unwary trespasser under the section on public protection.
If wildlife activity exists or can exist in or around an airport, the activity can have serious
consequences for the safe operation of aircraft. As a result, sections on how to address
wildlife hazard assessment and the reporting of a specific problem is required.
In order to ensure safe airport operations during periods of construction or
maintenance, airport managers are required to identify, mark, and report con-
struction or other unserviceable areas as they exist on the airport. More detailed
information on several of the ACM requirements follows in the paragraphs
below. Many special advisory circulars exist for each of the sections identified.
Guidelines and standards may be obtained through the FAA Regional or Local
Airports District Offices, FAA’s and AAAE’s Internet Web sites, the Government
Printing Office, and airport seminars and workshops.
Airport Self-Inspection
Regular self-inspections of the airport for hazardous conditions or those which
have the potential to become hazardous are the most critical actions that can be
taken to ensure the safety of airport operations. The airport manager’s primary
responsibility is to implement self-inspection and corrective procedures.
Primary attention in a self-inspection is given to operational items such as pavement
areas, safety areas, markings and signs, lighting, aircraft rescue and firefighting,fueling operations, navigational aids, ground vehicles, obstructions, public protection,
wildlife hazard management, construction, and snow and ice control. Inspection of
areas which have been assigned to individual air carriers, fixed-base operators, or
other tenants can be made the responsibility of the user, but airport management is
required to retain overall inspection supervision. This is because airport management
cannot delegate responsibility for operating the airport safely.
A successful safety self-inspection program has four key components:
(1) Regularly scheduled inspections of airport operating areas at least daily or
more often if operational activities or airfield lighting systems warrant.
(2) Continuous surveillance of certain airport activities such as fueling, construc-
tion, and airfield maintenance.
(3) Periodic evaluation of approach slopes, obstructions, or other activities and
facilities. The time interval could be weekly, monthly, or quarterly, depending
on the activity or facility.
(4) The monitoring of issues such as changing weather, high flight activity,
wildlife migration, or receipt of a complaint.
Regular self-inspec-
tions of the airport are
the most critical
actions that can be
taken to ensure the
safety of airport
operations.
7
Objective 4
An inspection of the
approach slope
surfaces for tree
growth would require
periodic evaluation.
If a control tower
reports a flock of birds
in the area, it is
necessary to conduct a
special inspection.
Such airport activities as
fueling, construction, and
airfield maintenance
require continuous
surveillance.
A special event such
as the arrival of the
President of the
United States requires
special inspection.
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Part 139 requires that inspectors be given initial and recurrent training regarding
the self-inspection program used by the airport. The regulation also defines the
items on which the individuals must be trained. All training records for inspec-
tors must be kept for a 24-month period.
At certificated airports, inspections are necessary before the first air carrier
operation in the morning, upon any major change in airport surface conditions,
when braking action reports by pilots or others are stated to be deteriorating, and
after an incident or accident. Other inspections may be required by the ACM or a
construction safety plan.
An effective safety inspection program establishes deficiency-reporting proce-
dures for prompt correction. This includes a checklist of items to be inspected, a
dissemination plan for informing others of the hazards, a work order system to
correct the deficiencies, and a maintenance log for monitoring the status and
currency of the process. Certificated airports must retain the regularly scheduled
inspection checklists for at least twelve consecutive calendar months.
Pavement Surfaces
The airport’s paved surfaces are included in a self-inspection program. Pavement
falls within two general categories: flexible or rigid. Flexible pavements such as
asphalt, dirt, or grass tend to compress under load, while rigid pavement resists
such compressibility. Portland cement concrete (PCC) is an example of a rigid
paved surface.
The two types of pavement, asphalt and concrete, have different characteristics.Asphalt can be laid without expansion joints or seams and is generally less
expensive than concrete to install, but requires higher maintenance. Since asphalt
is primarily a petroleum product, it is susceptible to oxidation from the sun’s
ultraviolet rays and the solvent action of fuel or oil. Being more rigid, concrete is
poured into distinctive slabs that require seams or joints to allow for expansion
and contraction. This contributes to its higher cost. The advantage of concrete,
however, is that it can withstand much higher aircraft loads than an equivalent
thickness of asphalt. It also resists weathering and oil or fuel spillage.
The wear characteristics and longevity of any pavement surface will be
affected by a number of different factors. When designing pavement surfaces,engineers consider:
Type of load (critical aircraft: utility, transport, military)
Distribution of load (landing gear type: single, dual, tandem)
l Volume and frequency of load (how often load is imposed)
Material quality (ratio of cement and stone or asphalt and bituminous aggregate)
Climatic effects (temperature variations, type of weather)
Mix of traffic (demands by different types of aircraft)
Under Part 139,
inspectors must
receive training and
all training records for
inspectors must be
kept for a 24-month
period.
At certificated
airports, inspections
are necessary before
the first air carrier
operation in the
morning, upon any
major change in
airport surface
conditions, when
braking action reports
by pilots or others are
stated to be deteriorat-ing, and after an
incident or accident.
8
Certificated airports
must retain the
regularly scheduled
inspection checklists
for at least twelve
consecutive calendar
months.
Asphalt can be laid
without expansion
joints or seams.
Compared with
asphalt, concrete is
more rigid, but it can
withstand much
higher aircraft loads
than an equivalent
thickness of asphalt.
Objective 5
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Roughness (smooth, coarse, porous)
Maintenance capabilities (preventive, routine, sealing)
Of the above factors, the two major elements contributing to pavement deteriora-
tion are weathering and imposed loads. The most detrimental factor to a paved
surface is water which seeps through and erodes the sub-base material. The water
weakens the supportive pavement resulting in pavement breakup.
General aviation pavement surfaces can suffer the same consequences, even
though they experience lighter loads, because the pavement is designed to carry
the most demanding aircraft expected to use the facility. Any sub-base deteriora-
tion, therefore, will result in normal loads now exceeding the pavement’s ability
to support them. Pavement potholes are typically formed when loads are imposed
over a pavement sub base area, weakened by water erosion.
Pavement Condition and Inspection
Part 139 requires that airport management maintain and promptly repair any
pavement surface available for air carrier use. If the airport is not certificated, any
pavement surface using federal grant dollars requires a similar level of response.
Airport management’s obligation is to prevent the overstressing of airport pave-
ments. Should pavement failure occur because the airport allowed aircraft opera-
tions that exceeded the pavement limitations, the cost to restore the pavement to
satisfactory condition may not be eligible for federal funding.
Acceptable aircraft weights are identified in the runway data table on the
airport layout plan. The ACN-PCN system of classification provides a stan-
dardized international airplane/pavement rating system replacing the variousS (single), D (dual), T (tandem), DT (dual tandem), LCN (load classification
number), and other rating systems used throughout the world. The ACN-PCN
system applies only to pavements with bearing strengths of 12,500 pounds or
higher. For pavements having lower bearing strengths, an older system using
letters still applies in the United States.
ACN is the aircraft classification number and PCN is a corresponding pavement
classification number. An aircraft having an ACN equal to or less than the PCN
can operate without restriction on the pavement. Therefore, the PCN is the
maximum pavement bearing strength for unrestricted aircraft operations.
To correct deteriorating pavement surfaces, or increase the strength of exist-
ing runways, taxiways, or ramp areas, a pavement overlay is commonly used.
Overlays can be either hot-mix asphalt (HMA) or concrete. Before an overlay
can be applied, any existing cracks or joint faults must be sealed to mitigate
reflective cracking. Reflective cracking occurs when an underlying pavement
crack works its way through a new overlay due to different coefficients of
expansion, contraction, or movement of the two surfaces. To help delay the
Erosion caused by
water seepage is the
most detrimental factor
affecting pavement
surfaces and conse-
quent maintenance.
Pavement potholesare typically formed
when loads are
imposed over a
pavement sub base
area, weakened by
water erosion.
If pavement failure
occurs because the
airport allowed
aircraft operations that
exceeded the pave-ment limitations, the
cost to restore the
pavement to satisfac-
tory condition may
not be eligible for
federal funding.
9
ACN—aircraft
classification number
PCN—a correspond-
ing pavement classifi-
cation number, indi-
cating the maxi-mum
pavement bearing
strength for unrestric-
ted aircraft operations
Objective 6
Reflective cracking
occurs when an
underlying pavement
crack works its way
through a new overlay
due to different coeffi-
cients of expansion,
contraction, or movement
of the two surfaces.
HMA—hot-mix asphalt,
one form of pavement
overlay that is used to
correct deteriorating
pavement surfaces or
increase the strength of
existing runways,
taxiways, or ramp areas
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progression of reflective cracks, pavement engineers have used different
methods such as coarse mix binder and engineering fabrics.
Until 1997, the FAA would not participate in the maintenance expense funding
of pavement surfaces. However, congressional reauthorization of airport im-
provement funding in that year provided for a pilot program to fund several
maintenance projects at selected airports in an effort to determine its cost-benefit.
The FAA design standards for pavements are based on a 20-year design life.
Asphalt pavement normally maintains good resiliency for 10 years, but
quickly deteriorates at a faster rate the second 10 years. Rehabilitating pave-
ments at the 11-15 year mark is projected to take less time and extend pave-
ment life at a lower cost than replacing the pavement at 20 years. Since 1995,
federal law has required airport management seeking funding for pavement
rehabilitation or reconstruction to have a Pavement Management System
(PMS) in place as a grant assurance condition.
The establishment of a Pavement Management System (PMS) helps to guideairport management and FAA decisions on use of federal monies for mainte-
nance. A PMS provides a consistent objective and systematic procedure for
setting priorities and schedules, allocating resources, and budgeting for pave-
ment maintenance and rehabilitation.
The regulations are specific for certificated airports regarding pavement
conditions that can affect the safety of aircraft. The regulations call for the
removal of pavement edges exceeding three inches between abutting pave-
ment and/or other areas, and cracks or holes that could impair directional
control. A hole is defined as an opening larger than five inches in diameter,
exceeding three inches in depth with an inside side slope greater than 45degrees. Any pavement crack or surface deterioration that produces loose
aggregate or other contaminants must be repaired immediately.
When inspecting pavement surfaces, airport management should be looking
for other types of surface deterioration. These include spalling, raveling, and
alligatoring; debris and/or foreign objects. These could cause aircraft or
engine damage; pavement depressions, undulations and/or bumps. Airport
management should also be observant for any pavement-edge obstruction that
could impede water runoff; the buildup of rubber deposits from aircraft tires;
the condition and/or visibility of pavement markings; the presence of erosionof soil at runway edges allowing water to seep underneath; and vegetation
growth through open or silted-in joints or cracks. Inspection of pavement
surfaces is required daily during air carrier activity.
Asphalt pavement does not necessarily wear out, but it ages through the
oxidation of the asphalt binder and by water causing it to loosen the fine
surface aggregates. A seal coat protects asphalt against the highly damaging
effects of gas, oil seepage and other pavement chemicals. Sealing asphalt
The FAA design
standards for pave-
ments—20-year design
life
Rehabilitating pave-ments at the 11-15 year
mark is projected to
take less time and
extend pavement life at
a lower cost than
replacing the pave-ment
at 20 years.
Asphalt pavement
maintains good
resiliency to ten years
but quickly deteriorates
at a faster rate thesecond ten years.
PMS—Having a
Pavement Management
System in place is a
federal requirement.
10
Spalling—fractured
edges in and around the
joint area of concrete as
a result of to the
tremendous pressures
generated during
expansion and contrac-
tion of the slabs
Pavement depressions,
undulations and/or bumps, erosion of soil
at runway edge,
vegetation growth,
etc., are all potential
runway problems.
Daily inspection of
pavement surface is
required during air
carrier activities.
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helps prevent water seepage in the porous asphalt structure, slowing water
damage caused by rain, snow, frost, freezing, and thawing.
Different means exist for the testing and evaluation of pavement surfaces. A
records and site inspection are the simplest means of evaluation. The sam-
pling and testing of material provide a more accurate assessment. Direct
sampling involves the removal of core samples and subjecting them to lab
compression tests, while another sampling method uses Non Destructive
Testing (NDT) techniques which does not require material replacement or
subsequent sealing around areas removed during coring. Ground penetrating
radar and the use of infrared thermography are examples of NDT testing.
An evaluation of a complete runway using inspection, surveying, sam-
pling, and NDT techniques helps to establish a Pavement Condition
Index (PCI). PCI is a numerical rating of the surface condition of a
pavement along its entire length and width. A PCI of 100 indicates no
defects, while a PCI of zero indicates no useful pavement life exists.
The FAA conducts an annual inspection of all Part 139 airports and arranges
for the annual inspection of most other public-use airports, either through the
state aviation organizations or by themselves. The results are reported as part
of the Airport Safety Data Program, using FAA Form 5010, Airport Master
Record. Runway pavement condition is classified as good (all cracks and
joints sealed), fair (mild surface cracking, unsealed joints, and slab edge
spalling), or poor (large open cracks, surface and edge spalling, vegetation
growing through cracks and joints).
Pavement Skid-Resistance
Guidelines and standards exist for the design and construction of skid-resis-
tant pavement, for pavement evaluation with friction measuring equipment,
and for the maintenance of high skid-resistant pavements. The braking per-
formance on pavement surfaces for aircraft, especially turbojet aircraft, is
critical to safe operations. Wet pavement, snow or ice covered pavements,
and those with rubber deposits or other contaminants can result in aircraft
hydroplaning or unacceptable loss of traction. These conditions can result in
poor braking performance and possible loss of directional control. Research
into improved braking action has resulted in two major areas of attention: (1)
high skid-resistant pavement surface design and evaluation, and (2) theapplication of proper maintenance techniques and procedures.
Hydroplaning occurs (1) when tires lose contact with the pavement surface
due to contamination of some form such as water, snow, ice, or rubber and
(2) when the right combination of aircraft speed, loading, and surface condi-
tions exist. It can occur at low speeds and to small piston aircraft as well as
much larger aircraft. There are three types of hydroplaning: dynamic, vis-
cous, and rubber reversion.
NDT—Non Destruc-
tive Testing tech-
niques, such as the use
of ground penetrating
radar and infraredthermography, are
used for evaluating
pavement surfaces
PCI — Pavement
Condition Index, a
numerical rating of the
surface condition of a
pavement along its
entire length and width
11
Hydroplaning occurs
(1) when tires lose
contact with the
pavement surface due
to contamination of
some form such as
water, snow, ice, or
rubber and (2) when
the right combinationof aircraft speed,
loading, and surface
conditions exist.
Three types of
hydroplaning—
dynamic, viscous, and
rubber reversion.
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Dynamic hydroplaning is a phenomenon that occurs on any surface. It gener-
ally occurs at high speed and is dependent upon aircraft load, speed, aircraft
tire pressure, and footprint area. A minimum fluid film density is also re-
quired. In dynamic hydroplaning, a wave of water builds up in front of a
rolling tire and allows the tire to ride up on a cushion of water and lose
contact with the runway surface. This results in loss of traction, steering
ability, and braking.
Viscous hydroplaning is a lubricating effect that occurs when a thin film of oil,
grease, dirt, rubber particles, or a smooth runway having water or other liquid on
the surface make the surface more slippery. Viscous hydroplaning prevents a tire
from making positive contact with the pavement and results in skidding.
Rubber reversion hydroplaning is less commonly known. It is caused by the heat
buildup beneath a tire footprint area due to friction. The heat causes the tire to
revert to its uncured state and form a seal that traps high-pressure super-heated
steam caused by the resultant friction. Rubber reversion hydroplaning occurs
primarily during landing and prevents a spin-up of the tire on touchdown.
Pavement grooving, asphalt porous friction courses, and the wire combing of
concrete surfaces have measurably improved the ability of runway surfaces to
shed water and provide for better traction. The most effective, economical
method of reducing hydroplaning is runway grooving. Pavement grooving
consists of forming or cutting closely spaced transverse grooves on the
runway surface. A porous friction course is a layer of asphalt aggregate with
voids in it that allow for better water drainage. Wire combing Portland ce-
ment just after it is poured provides a coarser texture for concrete surfaces,
which provide better friction capabilities.
The accumulation of contaminants in runway grooves reduces their water-
channeling capabilities, thereby decreasing the skid-resistance potential. In
simple terms, the water remains on the runway longer. For many airports, the
most persistent runway contaminant problem is rubber deposits from the tires of
landing jet aircraft. This requires maintenance to remove the rubber. Rubber
deposits occur primarily at the runway touchdown areas and can build up rapidly.
The removal of rubber deposits and other similar contaminants can be accom-
plished through a high-pressure water spray, the use of chemical solvents, high
velocity abrasive impact techniques, or mechanical grinding.
The effects of mechanical wear and the polishing action are directly depen-
dent upon the volume and type of aircraft traffic. Other influences on the rate
of deterioration are local weather conditions, the type of pavement; the
materials used in original construction, any subsequent surface treatment, and
airport maintenance practices. Structural pavement failure such as rutting,
raveling, cracking, joint failure, settling, or other indicators of distressed
pavement can also contribute to runway friction losses. The FAA expects
prompt repair by airport maintenance of these problems.
In dynamic hydro-
planing, a wave of
water builds up in
front of a rolling tire
and allows the tire to
ride up on a cushion
of water and lose
contact with the
runway surface. This
results in loss of
traction, steering
ability, and braking.
Runway grooving is
the most effective,
economical method of
reducing hydroplaning.
12
For many airports, the
most persistent
runway contaminant
problem is a deposit
of rubber from the
tires of landing jet
aircraft
The effects of
mechanical wear and
the polishing action
are directly dependent
upon the volume and
type of aircraft traffic.
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Pavement Friction Measurement
The operator of any airport with significant jet aircraft traffic should
schedule annual friction evaluations of each runway that accommodates
jet aircraft. Depending on the volume and type (weight) of traffic on the
runways, evaluations may become more frequent and necessary.
There are two basic types of friction measuring equipment available for
conducting friction surveys on runways during winter operations—
Decelerometers (DEC) and Continuous Friction Measuring Equipment
(CFME). Decelerometers, which can be either mechanical or electrical, are used
primarily to assess friction properties of runways during winter operations. They
are not approved for conducting runway pavement maintenance surveys or for
providing consistent measurement of wet runway surfaces. The Bowmonk and
the Tapley are the most commonly used decelerometers at airports. They are
normally placed or mounted inside the inspection vehicle.
CFME devices provide a continuous graphic record of the pavement surfacefriction characteristics with friction averages for each one-third portion of a
runway length. The devices are either towed or installed in ground vehicles
capable of conducting the friction test at speeds of 40 mph or 60 mph for the full
length of the runway. (This compares to speed of 20 mph for decelerometers.)
Several CFME devices have the ability to carry water and provide self-wetting
capabilities for conducting and evaluating wet pavement conditions. Both DECs
and CFMEs are eligible for federal funding under the AIP program.
The Greek letter Mu is used to identify friction values. It is a measurement
that gives an indication of the slipperiness of a paved surface. Mu values
range from zero to 100 where zero Mu has no friction properties and 100
represents a full contact and action between a tire and the pavement. Gener-
ally, Mu readings below 60 on normal runways are considered to be below
the FAA’s maintenance planning levels and corrective action is required.
During snow and ice conditions, Mu readings below 40 are reported to pilots,
because that is when the braking action of aircraft begins to be compromised.
A friction report of Mu 27 or less means that an aircraft may experience
directional control and/or braking difficulties and the airport must apply
surface treatment to increase the friction coefficient.
Airports without CFMEs often have devices that report braking action as Good,Fair, Poor or Nil. Those readings can be conveyed, but not if a device having Mu
reading capability is available. In those cases, only the Mu value is conveyed
since no correlation exists between the two different ratings. This is because
braking action is subjective, whereas a Mu value is quantitative. What is consid-
ered a “Good” braking action for one person may be “Poor” or “Nil” to another.
Three friction measurements are taken and reported by CFMEs for each runway
(one measurement for each third of a runway’s length) in the direction of takeoff
and landing. The reporting of friction readings is found under the section on
Airport Condition Reporting.
DEC—either
mechanical or electrica
decelerometers are used
primarily to assess
friction properties of
runways during winter
operations.
CFME—Continuous
friction measuring
equipment provides a
continuous graphic
record of the pavemen
surface friction
characteristics with
friction averages for
each one-third portion
of a runway length.
13
Objective 7
Mu is a measurement
that gives an indication o
the slipperiness of a
paved surface; Mu
readings of less than 60
on normal runways are
generally considered to b
below the FAA’s
maintenance planning
levels.
Mu readings below 40
are reported to pilots,
because that is whenthe braking action of
aircraft begins to be
compromised.
Three friction mea-
surements are taken
and reported by
CFMEs for each
runway in the directio
of takeoff and landing
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Movement and Safety Areas
FAR Part 139 requires management to identify those areas of the airport that are
to be used for air carrier operations. Known as aircraft movement areas (AMA),
they include runways, taxiways, and other areas of the airport that are used for
taxiing, takeoff, and landing of aircraft. They do not include loading ramps,
aircraft parking aprons, unpaved areas, or other areas that are not structurallycapable or that airport management has decided to preclude air carrier aircraft
from using. Those areas are known as non-movement areas.
A term commonly used at airports is the Air Operations Area (AOA). An
AOA, which really is a term originally identified under security regulations,
encompasses all portions of the airport designed and used for landing, taking
off, or surface maneuvering of aircraft. In that sense, AOA encompasses both
movement and non-movement areas. The AOA includes the runways, taxi-
ways, ramps, aprons, grass landing strips and parking areas, helipads or
hovering routes, and tie-down areas.
The distinction between movement and non-movement areas is necessary be-
cause not all areas of an airport available for aircraft maneuvering may be able to
meet the requirements of Part 139. Therefore, only those areas identified in the
ACM as being movement areas for air carrier aircraft are subject to the regula-
tions. Airport management is obligated to maintain to the standards and condi-
tions of the AMA as defined in an approved ACM. However, liability and practi-
cality concerns dictate that non-movement areas should not be neglected.
At airports with Air Traffic Control Towers (ATCT), the AMA generally
corresponds to those areas that are under the positive control of the ATCT.Airport and tower management sign Letters of Agreement (LOA) or Memo-
randums of Understanding (MOU) to identify those movement areas which
will be under the positive control of the ATCT, and those non-movement
areas that are the responsibility of airport management.
A safety area is a defined area comprising either a runway or a taxiway and the
surrounding surfaces, an area that is prepared or suitable for reducing the risk of
damage to airplanes in the event of an undershoot, overshoot, or excursion from
the runway or the unintentional departure from a taxiway. This safety area is
cleared, drained, and graded because it must be able to support aircraft in the
event they veer off the pavement. It must also be able to support emergency andmaintenance equipment responding to the aircraft. The safety area includes the
runway’s structural pavement, shoulders, blast pad, and stopways.
Safety areas have a total width range of 120 to 500 feet, depending on the aircraft
design group and the approach to the runway. Taxiway safety areas range from
49 to 262 feet in total width. Airport management is required to inspect daily the
safety areas for items such as rutting, rough and/or uneven terrain, mounds of
dirt, debris, and obstructions not mounted on frangible couplings. Objects lo-
Objective 8
AMA—Aircraft
Movement Areas—
include runways,
taxiways, and other areas of the airport
that are used for
taxing, takeoff, and
landing of aircraft.
AOA—Air Operations
Area— includes the
runways, taxiways,
ramps, aprons, grass
landing strips and
parking areas, helipads
or hovering routes, and
tie-down areas.
Only those areas
identified in the ACM
as being movement
areas for air carrier
aircraft are subject to
the Part 139 regula-
tions.
14
ATCT—Air Traffic
Control Towers
LOA—Letters of
Agreement
MOU—Memorandum
of Understanding.
A safety area is a
defined area compris-
ing either a runway or
a taxiway and the
surrounding surfaces,
an area that is pre-
pared or suitable for
reducing the risk of
damage to airplanes in
the event of an
undershoot, over-
shoot, or excursion
from the runway or
the unintentional
departure from a
taxiway
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cated in the safety area because of their function (i. e., lights, signs) must be
mounted on frangible couplings that have breakaway points no higher than three
inches above grade.
An often-cited statistic from on-airport aircraft accidents shows that about 90
percent of the aircraft involved remain within about 1,000 feet of the runway
departure end and 250 feet from the runway centerline. For this reason, runway
safety areas have extensions past the runway ends to provide a greater safety
margin for aircraft, which undershoot or overshoot the runway. Those dimensions
vary from 250 feet at general aviation airports to 1,000 feet for airports with preci-
sion approach runways. Some airports may have less than the FAA standard
dimension since they were grandfathered when the design standards changed.
Efforts are being made to reduce the severity of airport accidents and incidents by
improving the overrun areas where the majority of these situations occur. Newer
technology or alternative systems have been developed for those airports not able
to develop the 1,000 foot overrun due to existing structures, bodies of water, large
drop-offs, railroads, or highways. One is a soft ground arrestor system. It is aporous cellular concrete bed area at the end of a runway that deforms under the
weight of a heavy aircraft, resulting in major drag and deceleration of the aircraft.
It is designed to not deform under normal ground vehicle loads.
Markings, Signs and Lighting
The FAA classifies runways in a number of ways. They can be categorized
according to their pavement surface (asphalt or concrete), intended aircraft usage
(utility, transport, heliport, STOL port, or seaplane), or by type of aircraft ap-proach. The most common is according to the type of aircraft approach used for
the runway (visual, non-precision, or precision instrument).
A visual approach runway does not require navigational aids to assist the
pilot. It is intended to be used solely under Visual Flight Rules (VFR) condi-
tions; therefore, only visual cues for landing are necessary. A non-precision
runway approach is one that uses horizontal navigational guidance to help a
pilot line the aircraft up with the runway. A precision instrument runway
approach has both vertical and horizontal navigational guidance provided by
an Instrument Landing System (ILS) or Precision Approach Radar (PAR).
Both precision and non-precision approaches require FAA approval andpublication of the procedures to use the approaches.
The published approach establishes criteria for the type of lighting and
markings to be used for the runway and associated taxiways. In the 1920s,
airfields were first lighted by the use of fire pots or regular white electrical
lights placed around the perimeter of the whole open landing field. There
were no taxiways. As aircraft weights increased in the 1930s, paved surfaces
transformed the normally open grass or dirt landing area into very distin-
Safety Areas have a
total width range of
120 to 500 feet;
taxiway safety areas
range from 49 to 262
feet in total width.
The safety areas at
certificated airports
extend past the runway
end by 1,000 feet
15
The most common
runway classification is
by the type of aircraft
approach — visual, non-
precision, or precision
instrument.
A non-precision
runway approach is
one that uses horizon-tal navigational
guidance to help a
pilot line the aircraft
up with the runway,
whereas a precision
instrument runway
approach has both
vertical and horizontal
navigational guidance
provided by an
Instrument Landing
System (ILS) or
Precision ApproachRadar (PAR).
VFR—Visual Flight
Rules
ILS—Instrument
Landing System
PAR—Precision
Approach Radar
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guishable landing surfaces. The perimeter lighting then outlined the paved or
graded surface rather than the whole landing area.
Since those early days, the lighting and marking of runways and taxiways have
evolved, to increase the level of safety through standardization and uniformity.
This ensures pilot understanding. Airport management’s job is to maintain the
standards and uniformity through routine inspection and maintenance.
Airfield Lighting
Runway lighting systems are classified according to their intensity or brightness.
Depending on the type of approach, the systems will have High Intensity (HIRL),
Medium Intensity (MIRL), or Low Intensity Runway Lights (LIRL). The HIRL
and MIRL systems have different intensity levels or “steps,” whereas the LIRL
systems normally have one intensity setting or step. Intensity settings can be 1, 3,
5 or 7 steps, depending on the visibility conditions.
Many airports, not staffed 24-hours, have pilot-controlled lighting systemsinstalled. Keying the aircraft radio’s microphone switch several times in rapid
succession on a predetermined and published frequency activates these systems.
They provide a greater degree of pilot safety and reduce the airport’s operating
and maintenance costs.
In the ACM, clear instructions are required on how many and in what sequence
lights may be out before a system is considered inoperative. If more than three
lights in a row or more than 10 percent of a runway or taxiway route system are
inoperative, then standards are not being met. Snow, ice, or other conditions
obscuring the lights or causing outages may also make the system inoperative. A
Notice to Airmen (NOTAM) is required if standards are not met. The ACM is to
have detailed information on the lighting systems in place at the airport.
Runway edge lights are white. On instrument runways, amber lights replace
the white ones in the direction of landing for the last 2,000 feet or for one-half
the runway length, whichever is less. This provides visual safety information to
a pilot as he or she approaches the end of the runway. Taxiway edge lights have
solid blue lenses.
Threshold lights which mark the ends of the runway are of the colored split lens
type. The lens indicating the end of a runway to a departing aircraft is red whilethe other lens, which indicates the start of the runway for landing aircraft, is
green. Runway lights are directional in their focus through what is known as a
Fresnel lens. This lens requires the light bases to be properly aligned with the
runway and angled toward the landing approach.
In addition to the runway lights, several other lights can be found associated with
runways, depending on the approach. Precision runways can have Touchdown
Zone Lighting (TDZL), Runway Centerline Lighting (RCLS), and taxiway
Objective 9
Depending on the type
of approach, the
intensity of runway
lighting system ranges
from high to low.
16
NOTAM—Notice to
Airmen
If more than three
lights in a row or
more than 10 percent
of a runway or
taxiway route system
are inoperative, a
NOTAM is required.
Taxiway edge lights
have solid blue lenses.
Runway edge lights
are white.
Amber lights replace
the white ones in the
direction of landing
for the last 2,000 feet
or for one-half the
runway length,
whichever is less.
Runway lights are
directional in their
focus through what is
known as a Fresnel
lens.
Lights marking the end
of a runway to a
departing aircraft—red
Lights marking the
start of a runway to a
landing aircraft—green
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turnoff lighting. TDZL are in-pavement lights on both sides of the runway
centerline starting at 100 feet past the threshold and extending up to 3,000 feet
down the runway. RCLS are in-pavement lights on the centerline of the runway.
White in color for the majority of the runway, the white lens is alternated with
red starting 3,000 feet from the end of the runway. With 1,000 feet remaining,
they all become red.
Taxiway turnoff lights are in-pavement green lights that lead from the runway
centerline onto a taxiway or vice versa. Some airports have the green taxiway
center lights mark the complete route between the terminal and the active runway.
At U. S. airports having the capability of allowing air carriers to conduct opera-
tions when the visibility is less than 1,200 feet Runway Visual Range (RVR),
Surface Movement Guidance and Control Systems (SMGCS) are being imple-
mented. SMGCS is a system of guidance, control, and regulation of all aircraft,
ground vehicles, and personnel on the movement areas during low visibility
conditions. The intent of the SMGCS is to prevent collisions and ensure that
traffic flows smoothly and freely in low visibility conditions. Guidance andregulation of aircraft are accomplished through surface markings, stop-bar
lights, clearance-bar lights, hold-position lights, training, and installation of
advanced technologies such as Forward Looking Infrared (FLIR) systems,
Enhanced Vision Systems (EVS), Head Up Displays (HUD), and Global Posi-
tioning Systems (GPS).
Another light of importance to an airport is the rotating beacon. Rotating beacons
help to identify the airport location and area to a pilot. The light emitted from a
beacon is angled from two to ten degrees above the horizon, depending on the
surrounding terrain. Civil land airports have a white-green beacon.
As a safety measure, beacons are designed and built so that if one bulb burns out,
a backup bulb will activate. The system also provides information by a secondary
light or signal that indicates a bulb has burned out. If a beacon is activated during the
day, it represents conditions below those for flight under visual flight rules. It could
be that the ceiling is below 1,000 feet and/or the visibility is less than three miles.
Any changes to the lighting systems of a public-use airport, including pilot-controlled
lighting, require revision in the Airport Facilities/Directory (AF/D).
Airfield Signs
Airfield signs provide useful information to ground vehicle operators when driving
on the airport and to pilots during takeoff, landing, or taxiing. Airfield signs,
normally located on the left handside in the direction of travel (except for runway
exit signs), are intended to provide easy determination of where a pilot or ground
operator is, where he or she needs to go, and/or where he or she needs to stop until
further clearance is given. Signs and markings also identify boundaries of ap-
proach areas, ILS critical areas, runway safety areas, and/or obstacle free zones.
Taxiway turnoff lights
are in-pavement green
lights that lead from
the runway centerline
onto a taxiway or vice
versa
SMGCS—Surface
Movement Guidance
and Control Systems—
is a system of guid-
ance, control, and
regulation of all
aircraft, ground
vehicles, and personne
on the movement areas
during low visibility
conditions.
GPS—Global Posi-
tioning Systems
17
TDZL—Touch-Down
Zone Lighting
RCLS—Runway
Centerline Lighting
A rotating beacon
should be activated
when conditions exist
at an airport below
those established for flight under visual
flight rules.
Changes to the lighting
systems of a public-use
airport require revision
in the Airport Facilities
/Directory (AF/D).
Objective 10
Mandatory signs—
have white inscriptions
on a red background
and require an indi-
vidual at a controlled
airport to obtain
clearance before
proceeding
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Mandatory signs have white inscriptions on a red background and require an
individual at a controlled airport to obtain clearance before proceeding, or at an
uncontrolled airport to continue only with appropriate precautions. Mandatory
signs are used only in conjunction with runways with the exception of the no
entry sign. Location signs identify the taxiway or runway upon which the aircraft
or vehicle is located. They have yellow inscriptions on a black background. A
different type of location sign has black inscriptions on a yellow background;
these signs identify the boundary of the Runway Safety Area (RSA), Obstacle
Free Zone (OFZ), and ILS critical areas. The RSA, OFZ, and ILS signs are
installed only at airports with operating control towers and where pilots or
vehicles are often asked to report clear of a runway or critical area.
Directional signs provide information on the location and orientation of other
taxiways from the one where the pilot or ground operator is. They always
contain an arrow. Black inscriptions on a yellow background identify taxiways
leaving a runway or the direction of taxi routes. Where a taxiway ends, a taxi-
way-ending marker is normally installed. Destination signs are similar to direc-
tion signs except that they point toward a general location on the airport ratherthan a specific route. Sample destination signs are: APRON, FUEL, TERM(inal
area), CIVIL (aircraft area), MIL(itary area), PAX (passenger handling),
CARGO, INTL (international area), and FBO (fixed base operator).
A dot (%) between the inscriptions on a destination sign is read to mean “and”
while a hyphen (-) is used only on mandatory signs. A solid black vertical line
separates adjacent directional or destination insignia. Special informational signs
such as noise abatement procedures are black inscriptions on a yellow back-
ground. On runways, distance-remaining signs are placed along the runway at
Location signs—(1)
those with yellow
inscriptions on a black
background are used
for identifying the
taxiway or runway
where the aircraft or
vehicle is located (2)those with black
inscriptions on a
yellow background are
used for identifying the
boundary of the
Runway Safety Area,
Obstacle Free Zone,
and ILS critical areas.
Black inscriptions on a
yellow background
identify taxiways
leaving a runway or thedirection of taxi routes.
Taxiway directional
signs—with an arrow
and black inscription
against a yellow
background
Figure 1: Signing Examples for a Complex Airport
18
Destination signs—
similar to directional
signs but point toward
a general location on
the airport rather thana specific route, e.g.,
APRON, FUEL,
TERM (inal area),
CIVIL (aircraft area),
MIL(itary area), PAX
(passenger handling),
CARGO, INTL
(international area),
and FBO (fixed base
operator). A dot (%)
between inscriptions
mean “and.”
Special informational
signs have black
inscriptions on a
yellow background,
e.g., noise abatement
procedures.
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intervals of 1,000 feet. Located 20 to 75 feet from the pavement edge, depending
on the size of the sign, they have single white numbers on a black background.
Where signs cannot be installed and/or where there is a need for additional
information, directional guidance or location can be painted on the pavement.
Airfield Markings
Similar to signs, pavement markings provide information that is useful to both
pilots and ground vehicle operators. They can be grouped into four categories:
runway, taxiway, holding position, and others. Markings for runways are white,
as are helicopter-landing areas with the exception of hospital helicopter pads,
which are red. Taxiway centerlines, closed and hazardous areas, and holding
position indicators are yellow, even though they may be located on a runway.
Similar to pavement lighting, runway markings are determined by the type of
approach to the runway. Those common to all runways include centerlines,
designator, and holding indications. A non-precision instrument runway will
include threshold and aiming point markers. Those for a precision instrument
runway include all the previous plus touchdown zone and side stripes markings.
Visual runways, 4000 feet and longer, used by jet aircraft require aiming-points.
Located 1,000 feet past the approach end of the runway, aiming-points spot
where a jet on a normal glidepath will touch down. Touchdown zone markingsare spaced at 500 feet intervals and provide distance information according to
the number of rectangular bars.
Runway threshold bars are a number of longitudinal lines (usually eight but as
many as sixteen depending on runway width) that identify the beginning of a
runway. Visual approach runways do not have threshold markings. In the event
of construction, maintenance, or other activity causing a partial runway closure,
the threshold is relocated and airport management is required to file a NOTAM
Distance-remaining
signs are placed along
the runway at intervals
of 1,000 feet. These
signs have single white
numbers on a black
background.
Four categories of
pavement markings—
runway, taxiway,
holding-position, and
others
Runway markings
and helicopter-landing
areas — white, except
for hospital helicopter
pads, which are red
Taxiway centerlines
are yellow.
Table B: Runway Marking Elements (Source: FAA).
Visual Non-precision Precision
Marking Element Runway Instrument Runway Instrument Runway
Designation x x x
Centerline x x x
Threshold x1 x x
Aiming points x2 x x
Touchdown Zone x x x
Side Stripes x x x
1 On runways used or intended to be used, by international commercial transport
2 On runways 4,000 feet or longer used by jet aircraft
19
Visual runways, 4000
feet and longer, used
by jet aircraft require
aiming-points.
Touchdown zone
markers—Spaced at
500 feet intervals,
these markers providedistance information
according to the
number of rectangular
bars.
Runway threshold
bars — from eight to
sixteen longitudinal
lines that identify the
beginning of a runway
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and possibly remark the runway depending upon the duration of the activity. A
solid 10-foot wide white bar across the runway would identify a threshold that
has been relocated.
When it is necessary to site a threshold other than at the runway end, a displaced
threshold is used. This relocation is primarily needed because of an obstruction
in the runway approach. It is a white bar 10 feet in width across the runway.
A demarcation bar is a different type of marking across the runway. It distin-
guishes a displaced threshold from a stopway, blast pad, or taxiway that pre-
cedes the runway. The bar is three feet wide and painted yellow. Leading up to
the demarcation bar is a series of yellow chevrons indicating an unusable area
for landing, takeoff, or taxiing. Arrows and arrowheads help to identify andlocate a displaced threshold. If the arrows are used in a displaced threshold, they
are white in color.
Figure 2: Runway Markings
Figure 3: Special Runway Markings
20
Displaced threshold —
a 10-feet wide bar
placed across the
runway when there is
an obstruction in the
runway’s approach.
Demarcation bar — 3-
feet wide yellow bar used to distinguish a
displaced threshold
from a stopway, a blast
pad, or a taxiway that
precedes the runway
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Other types of markings exist for the runways and taxiways. Shoulder stripe
markings are used on both runways and taxiways to identify non-structural
adjacent pavement. Sidestripes are used on runways and taxiways to provide a
visual contrast between the usable surface boundaries. They are one continuous,
solid white line on runways and two parallel continuous yellow lines on taxi-
ways. An exception is where a taxilane is defined on an apron area. Instead of
two solid lines, the markings consist of broken lines.
Taxiways at public-use airports are required to have taxiway centerlines and
runway hold-position markings. A taxiway centerline is a single continuous
yellow line, even where it extends onto the runway (called lead on/off lines).
Taxiway hold-position bars are four yellow parallel lines—two dashed lines and
two solid ones. The two dashed lines are closest to the runway. Aircraft or
vehicles approaching the runway will encounter the two double solid lines,
which require authorization from the ATCT to cross if a control tower is in
operation at the airport. Yellow in-pavement lights help to further distinguish the
hold-position marking.
At non-controlled airports, extreme diligence is used when approaching a hold-
position line. Safe practices would have the pilot or vehicle operator announce
over the radio his or her entry onto the runway before crossing the hold lines.
Upon exiting the runway, the pilot encounters the double dashed lines first, and
once passing both the dashed and solid lines, the pilot would announce being
clear of the runway.
Some airports have critical areas associated with navigational equipment. An
aircraft, piece of equipment, or vehicle in the critical areas can disrupt the
navigational signal. To keep aircraft and vehicles clear during IFR conditions, a
yellow ladder-type marking is used.
Airports with VOR facilities may have VOR ground checkpoint markings and
signage installed. The checkpoints allow pilots to calibrate aircraft instruments
on the ground. The checkpoint marking is a circle with an arrow directed toward
the navigational aid and is located within one-half mile of the VOR. The mark-
ing is two concentric circles—the outside white and the inside yellow—with a
yellow arrow. It is supplemented by a sign identifying the checkpoint and giving
the VOR identification letters and the course radial. If available, DME informa-
tion is also listed. The signage letters are black on a yellow background.
Closed runways and taxiways are marked by yellow X’s placed to obscure each
runway number, or are placed at the beginning and end of a taxiway. New
technology has resulted in raised lighted X’s as a substitute. Permanently closed
runways or taxiways additionally require disconnecting lighting circuits and
obliterating pavement markings. The marking of construction areas requires
special attention in the construction safety plan to ensure visibility and meaning.
Sidestripe markings —
one continuous solid
white line on runways
and two parallel
continuous yellow
lines on taxiways,
used to provide visual
contrast between the
boundaries of the
usable surface
Taxiways at public-
use airports are
required to have
taxiway centerlines
and runway hold-
position markings.
A taxiway centerline
is a single continuous
yellow line, even
where it extends onto
the runway.
Taxiway hold-position
bars—four yellow
parallel lines, two
broken and two solid.
Solid are on the
taxiway side and
broken are on the
runway side.
21
Checkpoint mark-
ing—a circle with an
arrow directed toward
the navigational aid,
located within one-
half mile of the VOR
Markings for closed
runways and taxi-
ways—yellow X’scovering up each
runway number or at
the beginning and end
of a taxiway
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At airports having authorized Land and Hold Short Operations (LAHSO) for
two intersecting runways, or where the runway is used as a taxiway to another
runway, a yellow double solid and double dash hold-position marking extends
across the runway to identify the hold-short position. It is supplemented with
white on red signs adjacent to the runway. In-pavement lights help to distinguish
the hold-position line on Category II and III ILS runways. For airports required
to have a SMGCS, the stop-bar lights would be red.
One component of a SMGCS is painted taxiway markings that complement the
lighted guidance and informational signs. A SMGCS also requires elevated or
in-pavement runway guard lights, green centerline, and lead-on lights for pre-
ferred taxi routes, taxiway lights, clearance bar lights, gate-designator markings,
geographic hold-position markings (“ spots”), and yellow elevated runway guard
lights at hold positions (“ wig-wags”) along with in-pavement lights.
Vehicle roadway markings are intended to reduce the risk of an aircraft and
vehicle accident on the AMA or AOA. Driving lanes are normally like those on
highways, solid white boundary lines with a white broken centerline. An alter-native is to use white “zippered” (required for SMGCS) markings. Outside of
the AOA, markings should conform to those in the Department of
Transportation’s Manual on Uniform Traffic Control Devices.
For pavement markings two choices of paint exist: water-based (latex) or oil
based. Similar to the application of pavement sealers, pavement paint has less
friction than the asphalt or concrete it covers. The addition of silica sand or glass
bead can provide added texture to improve the friction properties of the painted
surface. Glass beads, which reflect light, are required to be added to the paint to
make the markings more conspicuous.
Two other types of markings/piloting aids can be found at airports: a compass
rose and a segmented circle. A compass rose is a painted or other marking that
is located on a surface large enough for aircraft to maneuver and be aligned to
the different magnetic headings marked on the pavement. The compass rose is
used to help calibrate aircraft magnetic compasses.
The segmented circle marking is actually a series of objects on the ground
designed to give traffic pattern and wind information to pilots in the air. A
segmented circle is a series of highly visible white or yellow markers arranged
in a circle to help a pilot identify important landing pattern and wind directioninformation. A segmented circle is required for airports serving any air carrier
operation and when there is no control tower in operation.
Inside the segmented circle is a wind indicator. Wind indicators pivot in the
wind and can be a tetrahedron, a wind cone (windsock), or a combination of
both. A landing strip indicator extends from the segmented circle for each
runway. If a right-hand traffic pattern exists, a traffic pattern indicator extends
from the landing strip indicator.
LAHSO—Land and
Hold Short Operations
22
A compass rose
marking is used to
help calibrate aircraft
magnetic compasses.
Segmental circle
marking—a series of
highly visible white
or yellow markersarranged in a circle,
with a wind indicator
inside, to help pilot
identify important
landing pattern and
wind direction
information
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Depending on the model, wind cones (socks) at airports have a minimum open-
ing diameter of 18 inches, which provides an indication of wind speeds from 5
to 50 miles per hour. The cones have a distinguishing color of white, yellow, or
orange. The support structure should be orange in color.
Additional wind cones are required at airports certificated under Part 139 for each
runway available for air carrier use. These supplemental wind cones are installed at
the end of each runway, or at least at a point visible to the pilot while on final ap-
proach and prior to takeoff. For those airports open for air carrier operations during
hours of darkness, all wind direction indicators require lighting.
Snow and Ice Control
Airport managers have a duty to ensure the safety of operations at their facili-
ties. Part 139 requires a snow and ice removal plan that is current and complete,
to meet local conditions. Snow, ice, slush, and standing water degrade the
coefficient of friction; reduce braking and directional control; and impede
aircraft acceleration. Acceptable limits vary by aircraft, but most jet aircraftflight manuals limit their particular aircraft to landing with no more than one
inch of slush or standing water on the runway, and to taking off with no more
than one half inch accumulation.
The requirement for airport operators, therefore, is to remove as expeditiously as
possible all snow, ice, and slush so as to maintain runways, high-speed turnoffs,
and taxiways in a “no worse than wet” condition. Although snow is an important
and serious problem in airport maintenance operations, ice is the most difficult
problem to cope with and presents the greatest hazards to aircraft operations. A
NOTAM is issued whenever contaminants exist on the runway.
The snow and ice control plan required in an ACM includes instructions and
procedures for the following:
1. The prompt removal or control of snow, ice, and slush on each AMA.
2. The positioning of snow off AMA surfaces so that all air carrier aircraft propellers,
engine pods, rotors, and wingtips will clear any snowdrift or snow bank.
3. The selection and application of approved materials for snow and ice control.
4. The timely commencement of snow and ice control operations.
5. The prompt notification to all air carriers using the airport when there is less
than a satisfactorily cleared AMA for the safe operation of aircraft.
Since snow and ice conditions are considered an emergency situation, the timely
removal or treatment of either is important. A snow plan identifies and classifies
priority areas according to operational needs. Priority 1 areas generally are
ARFF access routes to the primary runway in use, the primary runway and its
associated taxiway routes to and from the terminal, and emergency service roads
into the airport if ARFF services are located off the airport. Clearance times are
based on the ability of the maintenance staff and the capability of equipment to
clear pavement surfaces.
Objective 10
Most jet aircraft flight
manuals limit their
particular aircraft to
landing with no more
than one inch of slushor standing water on
the runway, and to
taking off with no
more than one half
inch accumulation.
23
Ice is the most
difficult problem to
cope with and
presents the greatest
hazards to aircraft
operations.
Objective 11
Snow is first removed
from the primary
runway in use and its
associated taxiway
routes to and from the
terminal, ARFF
access routes and
emergency service
roads into the airport
if ARFF services are
located off the airport.
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Snow and Ice Plan
Every fully certificated airport located where snow or ice regularly occurs is
required to have a written plan stating the procedures, equipment, and materials
to be used by the airport in removing snow and ice. Elements included in the
plan are: preseason preparation, snow committee composition, snow desk or
snow control center location, equipment, personnel training, weather reports,field condition reports, clearance criteria, clearance priorities, supervision, and
communications. A snow plan needs to be flexible enough to allow snow and ice
removal operations to change with weather and operational conditions.
Airports that are required to have a snow plan should have a snow committee as
part of the plan. The committee should be composed of representatives of
airport management, the airline flight operations department, fixed-base opera-
tors, the ATCT, the flight service station, Airway Facilities (AF), the National
Weather Service, other meteorological services, and/or other interested or
concerned parties. Air carriers normally provide information on aircraft opera-
tional limitations and assist in evaluating pavement surface conditions. Airportsin frequent or heavy snowfall areas have a “Snow Desk” or “Snow Control
Center,” which is a special operation for coordinating all snow and ice control
activities.
All snow removal vehicles operating on runways and taxiways must be in radio
communication or under the control of a radio equipped vehicle. The snow
control center facilitates communication between the ATC tower, snow and ice
control equipment and/or supervisors’ vehicles, and other support elements.
The snow control centers are to inform air carriers and the ATC of expectedrunway opening and closing times, and to serve as a prime source of field
condition information. They also ensure a timely response to a snow or ice
removal event by obtaining and monitoring accurate information about an
approaching storm and its likely effect on airport surfaces. The snow or ice
removal task can be reduced and costs lessened by a prompt, effective response
to a storm warning.
Proper application of approved chemicals on the pavement before or during the
very early stages of a snowfall will reduce the likelihood of compacted snow
bonding to the pavement. Prompt treatment will also reduce the effort needed
for either mechanical or chemical means of removing the snow. Freezing rainwill bond to a cold pavement surface and requires special treatment, depending
on the pavement surface temperature. If the pavement surface temperature is
below freezing, chemical application may be the most effective control measure.
If the pavement surface temperature is above freezing and a frozen rain (slush)
develops, brooming is a more effective method of control.
To help determine the best timing for de-/anti-ice application or snow removal,
the use of friction measuring equipment can be beneficial, or instruments that
Objective 12
Basic components of a
snow and ice plan—
(1) preseason
preparation,
(2) snow committeecomposition,
(3) snow desk or
snow control center
location,
(4) equipment,
(5) personnel training,
(6) weather reports,
(7) field condition
reports,
(8) clearance criteria,
(9) clearance priorities,
(10) supervision, and
(11) communications.
24
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detect pavement conditions can be installed. Pavement condition sensing instru-
ments are sensors, which are embedded in the pavement to measure surface
conditions. They serve three functions: (1) they provide a precise measure of the
pavement temperature; (2) they indicate the presence of water, ice, or other
contaminants; and (3) they transmit this information to the snow control center
for incorporation into the decision-making process for the most appropriate
snow and ice control strategy. Both friction measuring equipment and surface
sensing instruments are eligible for funding under AIP.
Many factors influence a pavement’s temperature. Factors such as surface color
and composition, wind, humidity, solar radiation, traffic, and the presence of
residual deicing chemicals or other contaminants all need to be taken into
consideration. Since pavement temperature lags behind air temperature, use of
air temperature to infer the condition of the pavement surface is imprecise and
can be misleading. Ice will not form unless the pavement temperature reaches
the freezing point; therefore, knowledge of the direction and rate of change of
pavement temperature can provide a predictive capability for the formation of
ice. This is the benefit of a pavement sensor system.
De-ice and Anti-ice Compounds
The formation of frozen precipitation on an airport’s paved surfaces and on
aircraft is a serious concern. Snow and ice can degrade an aircraft’s performance
to the point where (1) surface maneuvering is impeded, (2) the generation of
speed or lift is diminished for takeoff, or (3) braking action and stopping dis-
tance become marginal when landing. For the air carriers, the FAA prohibits
takeoff when snow, ice, or frost is adhering to wings, propellers, control sur-
faces, engine outlets, or other critical surfaces on the aircraft.
For airport pavements, different types of chemicals or liquids may be used for
preventing or removing snow and ice accumulations. Chemicals that are avail-
able for use are: urea, acetate-based compounds, and sodium formate. Urea is a
solid synthesized crystalline granular compound that is often used as fertilizer. It
works for temperatures down to about 15 degrees Fahrenheit. Acetate-based
compounds are potassium acetate (Cryotech), calcium magnesium acetate
(CMA), or sodium acetate (Clearway 2). Another compound, sodium formate, is
marketed under the Safeway SF name. Potassium acetate can work down to -50
degrees Fahrenheit depending upon the dilution strength.
Polypropylene glycol and ethylene glycol are the two liquids approved for use
as deicing existing buildups or for the prevention of ice formation (anti-ice). De-
icing chemicals and liquids work by lowering the freezing point of the water or
liquid mixture. Anti-ice chemicals or fluids are applied prior to ice formation to
prevent bonding of the ice to the pavement. Application rates of de-/anti-icing
fluids vary depending on ice and snow accumulations and overall weather
conditions. The chemical costs to deice a runway and taxiway can become very
expensive.
25
Objective 13
Both friction measur-
ing equipment and
surface sensing
instruments are eligible
for funding under AIP.
Objective 14
Chemicals available
for deicing and snow
removal—urea,
acetate-based com-
pound, and sodium
formate
Liquids approved for
deicing—polypropy-
lene glycol and
ethylene glycol
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In applying de-icing compounds, whether on pavement or on aircraft, the ratio
of water and glycol mixture is dependent upon the eutectic point desired. The
lowest temperature that a chemical melts ice occurs with a specified amount of
chemical mixture. That temperature is called the eutectic temperature, and the
amount of chemical is called the eutectic composition. Combined, they are
called the eutectic point. Ice will form on a pavement or aircraft surface in one
of four methods: (1) radiation cooling, (2) freezing of cold rain, (3) freeze-thaw
of compacted snow, or (4) freezing of ponded or melted water. All anti-icing and
de-icing compounds are dispensed on the basis of the pavement temperature or
the temperature of the aircraft skin, not air temperature.
Compared with liquid de-icers, solids can be spread simultaneously with sand
and require less equipment and fewer operators to spread. Liquid de-icers
generally require special tanks and pumping stations. Chemical snow and ice
control is expensive and affects the environment. Urea and potassium acetate do
different things to the environment.
As urea degrades, it turns into ammonia nitrate, which has high biochemicaloxygen demand (BOD) and toxicity. Both properties are detrimental to the
environment. The benefits of liquids are for lower BOD and toxicity. Among the
acetates used on runways, ammonia acetate has the greatest toxicity effect. A
drawback to using liquid, however, is that it adds bulk to snow and slush,
thereby allowing greater potential for windrow dams to be formed. Also, using
liquid deicers is more expensive than using solid de-icers. Because each
airport’s snow and ice conditions will vary, sometimes a combination of the two
methods is most effective. Safety should always come first when considering the
application of anti-/de-ice material. The airport operator should work closely
with the state’s environmental departments to ensure the legality and effects any
chemical used will have on the environment.
Aircraft De-icing
Because aircraft cannot take off when snow, ice, or frost is adhering to the
wings, propellers, control surfaces, engine outlets, or other critical surfaces, the
aircraft must be de-iced. Aircraft de-icing is accomplished by spraying one of
several types of heated aqueous solutions (water/glycol) onto critical aircraft
surfaces. The heat of the solution and the force of the spray melt and remove the
ice/snow/frost, and the antifreeze properties of the solution prevent refreezing.
The spent solution falls to the ground and follows whatever natural drainagecourse exists.
The two most common types of aircraft anti-/de-icing fluids are distinguished by
their thickness or viscosity. The first solution, known simply as Type I, is a
mixture of glycol and water that is heated to 180 degrees F. Applied to clean
frozen precipitation on the aircraft, Type I fluid protects aircraft from snowfall
for approximately 15 minutes, but it provides only 3 to 5 minutes of holdover
protection from freezing rain. Type I is orange in color.
BOD—biochemicaloxygen demand
Using liquid deic-
ers—more expensive
than using chemical
deicers
26
The eutectic tempera-
ture—the lowest
temperature that a
chemical melts ice
The eutectic composi-
tion—the amount of
chemical mixture thatmelts ice at the
eutectic temperature
Anti/de-icing fluids
are distinguished by
their thickness or viscosity.
Type I fluid—a
mixture of glycol and
water heated to 180
degrees F; protects
aircraft from snowfall
for about 15 minutes
and from freezing rain
for 3 to 5 minutes
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Type IV fluid is a thicker water and glycol mixture that uses a polymer as a
thickening agent and is green in color. It does not need to be heated before it is
applied. Considered an anti-icing solution, Type IV fluid is used mostly during
heavy snowfall. Once it is applied, the fluid adheres to the aircraft’s outer
surface and does not run off until take off. However, if ice or snow has formed
on the aircraft, it must be cleaned off first using Type I fluid. Type IV fluid
holdover times can protect aircraft from heavy snowfall for up to 45 minutes.
Airport operations personnel should be familiar with the types of chemicals used
on their airport, the correct response to spills, cleanup requirements and the
proper techniques for handling such chemicals.
The use of Type I and IV fluids is expedient and efficient, though the cost of the
solutions has made it expensive and there are environmental concerns associated
with them. Neither ethylene glycol nor propylene glycol is particularly toxic,
though the EPA lists ethylene glycol as a hazardous substance. A greater con-
cern exists for the environmental effects of de-icing. Each glycol compound is
known for its biochemical oxygen demand (BOD) and for aquatic toxicity. Of
the glycols, Type IV has higher toxicity and BOD.
Air carriers and airports have a leading role and joint responsibility in the glycol
mitigation process. The carriers must produce and update a plan of operations
that is acceptable to the airport operator and the environmental agencies. To help
minimize the effects of aircraft deicing on the environment, airports are encour-
aged and even required to construct separate de-icing facilities or to acquire
equipment that can collect the fluid on the ground.
Airport management can construct, within FAA standards, either centralized or
remote aircraft de-icing facilities. De-icing facilities at terminals or on apron areas
are considered centralized. Those located on taxiways or near departure runways areconsidered remote. Siting remote facilities near departure runways minimizes the
taxiing time between treatment and takeoff. Such facilities also compensate for
changing weather conditions when icing conditions or blowing snow is expected to
occur along the taxi route taken by aircraft to the departure runway.
The primary factor for siting deicing facilities is aircraft taxi time. Beginning
with the start of the last de-/anti-icing treatment and ending with a takeoff
clearance, the taxi time must be within the holdover time of the fluid in order to
remain effective.
The acquisition or use of vehicles that vacuum or otherwise collect glycol is
another technique for mitigating the effects of glycol runoff. Many airports use
this method because it is an economical approach to the problem of glycol
recovery. The collected glycol is then stored or otherwise deposited into a
facility that will recycle or process the glycol.
Another system for de-icing aircraft has been developed. Installed in a large
open-ended hangar, this system contains infrared sources suspended from the
Type IV fluid—a
thicker water and
glycol mixture that (1)
uses a polymer as a
thickening agent, (2)
does not need to be
heated before it is
applied, and (3) has
higher toxicity and
BOD
27
Siting remote
facilities near departure runways
minimizes the taxiing
time between
treatment and takeoff
Acquiring or using
vehicles that vacuum
or collect glycol
mitigates the effects
of glycol runoff.
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ceiling to melt ice and snow from the surfaces of aircraft towed through it. The
technology continues to be tested.
Snow Removal Equipment
Snow removal equipment requirements are based on the annual operations at an
airport and the amount of Priority 1 surface area to be cleared in a specified timeperiod. Commercial service airports that provide scheduled air carrier service
and experience snow conditions as presented in AC 150/5200-30A should have
sufficient snow and ice control equipment, chemicals, and personnel to meet the
removal standards established in the ACM.
Snow and ice can be removed in one of two ways, either mechanically or chemi-
cally. The four mechanical methods of snow removal include rotary blowers or
throwers, plows, broom sweepers, and loaders. The chemical methods include
material spreaders that disperse de-/anti-ice granules or liquid.
Rotary Snowblowers
The rotary snow blower or thrower is the primary mechanical device for removal
of hazardous snow accumulations such as windrows and snow banks. Rotary
snowblowers are used primarily to cast heavy concentrations of snow away from
airport operational areas such as the runways and taxiways. The equipment can
be self-propelled or attached to a carrier vehicle and uses either one or more
rotating elements (single or two-stage units) to break up and discharge the snow.
The term carrier vehicle represents the various self-propelled prime movers
(combination truck chassis, body, and engine) that provide the power necessary
to move snow and ice control equipment during winter operations.
Single-stage rotary plows use one rotating device to accomplish both the
breakup and the casting of snow. Two-stage rotary plows break up the snow in
one step and discharge in the second. Impellers, which cut and gather the snow,
can be of blade, auger, or ribbon type. Impellers, which cast the snow, can be of
a web or disk design. There are various types of snowblowers available. Their
different snow removal capacities are based on their speed and casting distance.
Snow Plows
Displacement plows consist of a cutting edge to shear snow from the pavement
and a moldboard to lift and cast the dislodged snow to the side of the cleared
path. The cutting edge may ride in contact with the pavement or be held a small
distance above it by means of shoes or caster wheels. Displacement plow sizes
are classified as follows: small (6-10 feet), intermediate (10-15 feet), large (15-
22 feet), and extra large (greater than 22 feet).
The plows themselves can be further classified as to their function and purpose.
Typical plows are: one-way fixed angle, power reversible, rollover power reversible,
Snow removal
equipment require-ments are based on the
annual operations at
an airport and the
amount of Priority 1
surface area to be
cleared in a specified
time period.
The four mechanical
methods of snow
removal include rotary
blowers or throwers,
plows, broom sweep-ers, and loaders.
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power reversible with folding wings, flexible reversible, ramp dozer, expressway,
and vee type. Plows are most commonly mounted on the front of a carrier vehicle,
but they may also be mounted on the side or underneath the vehicle.
A ramp dozer is used primarily in confined areas that require wide to extra-wide
swath plowing, but it may also be used to transport and dump snow. A ramp
blade can be equipped with side plates to contain snow and prevent spillage.
An expressway plow provides the speed characteristics of a rigid plow and the
cleanup ability of a reversible plow. The plow has bulldozing capabilities and, if
horizontally adjusted, has the ability to cast snow to the right or left. Vee-type
plows can tackle high drifts and heavy snow. Side-mounted extension wings
increase the swath of the front-mounted plow. Leveling wings are used for
windrow and snow bank leveling/trimming operations. Underbody mounted
scraper blades provide constant ground pressure on the pavement surface.
Combined with serrated cutting edges, they are especially useful in scarifying
ice which helps to retain applications of deice chemicals or liquids.
Sweepers
Snow sweepers or brooms are used primarily to clean up the residues left on the
pavement surface by a plow or blower, or in sweeping and cleaning debris from
airport operational areas. They incorporate high-speed brooms that consist of a
number of brush sections, which may be front-mounted to a carrier vehicle
(attached or integral), underbody-mounted, or mounted on a trailer towed by a
carrier vehicle. All are capable of sweeping wet, slushy snow as well as fine dry
snow from pavement surfaces. A sweeper can be complemented by an airblast
system, which is located behind the brush assembly. A sweeper airblast system
is used to sweep the pavement area clean of snow, slush, sand, and other debris;
help dry the pavement surface, and clear snow from around runway lights.
Four different types of sweepers are used on airports: (1) pushed, (2) towed, (3)
underbody, and (4) band sweepers. The pushed sweeper precedes the carrier
vehicle while the towed sweeper is fixed to a trailer and is towed by a conven-
tional carrier vehicle. Towed sweepers are available in three types of drives:
straight mechanical, variable speed mechanical and variable speed hydrostatic.
The underbody airport sweeper is a large multipurpose unit that is pulled by a
carrier vehicle and is capable of plowing and sweeping snow and debris simulta-
neously. The band sweeper is similar to a front-mounted broom except it uses acontinuously turning horizontal band that is made of reinforced rubber. The
band has a number of protruding vertical ribs that are capable of moving snow
to the right and left of the travel path.
The focal point of any sweeper is the brush assembly. It must not only sweep
snow and slush from pavement surfaces at a specified speed, but also lift and
cast these materials off the surfaces and away from the path of travel. Brushes
come in different shapes and sizes. They can be mounted on a single tubular
29
Snow sweepers or
brooms are used
primarily to clean up
the residues left on
the pavement surface
by a plow or blower,
or in sweeping and
cleaning debris from
airport operational
areas
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core or on several abutting cores, both of which receive power directly from the
carrier vehicle engine or an independent engine.
The choice in brush design and bristle composition depends on an airport’s
particular needs and the nature and type of snow normally received. Generally,
brushes having a mixed polypropylene/wire bristle composition will provide the
best overall sweeping results. Brushes are most effective when their contact with
the pavement surface produces a “flicking action” that dislodges snow and slush
and leaves a clean dry surface behind. Brush bristles are made of polypropylene
plastic (poly), wire, or a combination of one-half poly and one-half wire.
Three different types of brushes are available for use on airport sweepers:
wafers, tufted wire sections, and cassettes. Wafers are by far the most popular
type of brush used on airports.
Material Spreaders
The function of a material spreader is to provide a continuous, unrestricted,accurately metered flow of granular or liquid material to a pavement surface
over a predetermined spread area. A spreader unit consists of a material storage
compartment, a feed mechanism to carry the material to the discharge opening,
a metering device to control the discharge rate, and a distribution mechanism.
Depending on the type, spreaders are capable of spreading dry and liquid chemi-
cals and abrasives. Liquid material spreaders apply fluids to the pavement
surfaces through a spray applicator system consisting of a supply tank, pump,
flow rate monitor, and a spray bar equipped with nozzles. Tank capacities
usually range from 500 to 4,000 gallons.
Two methods exist to increase the friction coefficient of an iced or snow-packed
surface: (1) scarify the ice with a serrated blade and (2) apply granular material
(abrasives) to the surface. The use of abrasives needs to be carefully controlled
to reduce engine ingestion in turbojet aircraft. When applying abrasives, care is
used to help them adhere to the ice or snow since they can easily be blown away
by wind or scattered by aircraft operation. There are three approaches to reduc-
ing loss of abrasives: (1) they can be heated to enhance embedding into the cold
surface, (2) the granules can be coated with an approved de-icing chemical in
the stockpile or in the distributing truck hopper, or (3) diluted de-icing chemical
can be sprayed on the granules or the pavement at the time of spreading.
Snow and Ice Removal Techniques
It is important that any snow plowed off the runways not be of a height that will
interfere with pilot visibility or the wings, engines, and propellers of aircraft.
Furthermore, snow cleared from the runways should not be deposited within a
NAVigational AID (NAVAID) critical area.
NAVAID —Naviga-
tional Aid
The best type of snow
sweeper—made of
polypropylene and
wire bristle
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Snow should be plowed to the prevailing downwind side of the runway to
reduce drifting. Eliminating windrows at the runway edge can also reduce the
formation of drifts onto the runway. These drifts, often called finger drifts,
frequently take the form of long, intermittent, and possibly narrow snow projec-
tions, which taper in width and height and can cause loss of aircraft directional
control. Snow fences can be used to minimize snow accumulation around
NAVAIDs and other sensitive facilities. Snow fences should not be placed so
that they penetrate any critical surfaces, and they should be outside of the
runway safety area.
If there is insufficient storage space for snow near the areas to be cleared and no
melting or flushing means are available, hauling snow to a disposal site may be
necessary. Careful consideration must be given to drainage when selecting a land
disposal site, as the ground can remain snow covered or wet long after all other snow
has melted. Seasonal vegetative growth can be delayed. Some airports have disposal
pits with melting devices in the ground to handle snow removal demands.
In heavy snow areas, the marking of edge lights by the placement of flexiblemarkers near the lights helps snow removal crews and pilots. The markers are
normally of a high contrast color such as international orange, which enhances
visibility. The height of the markers should be six inches outside the propeller
arc of the most critical airplane using the airport, and the markers need to be
securely fastened in place to avoid creating a foreign object damage (FOD)
hazard.
A NOTAM should be issued for the following winter operating conditions:
braking action reports, friction measurements, snow depths, plowed runways,
runway sanding or de-icing, snow banks, and runway light obscuration. The
procedures for pilot braking action reporting and runway friction reporting aregiven in the Aeronautical Information Manual (AIM). Relative to snow and
slush, depths normally greater than one-half inch require NOTAM publication.
The ACM is also the source for information regarding the placement of snow
banks near a runway, taxiway, or apron; though a snow bank exceeding 12 inches
is considered the norm for requiring a NOTAM.
The height of a snowbank on an area adjacent to a runway, taxiway, or apron
should be reduced to provide wing overhang clearance and preclude operational
problems caused by ingestion of ice into turbine engines or propellers striking
the banks. The maximum snow height profile developed for safe operationsshould be for the most demanding airplanes using an airport. This ensures that
props, wing tips, etc., do not touch the snow when a main wheel is located at the
edge of the full-strength pavement.
Some airports contract with private companies or municipal crews to conduct
snow removal operations. The principles of ensuring safety of operations apply
to them also. Any agreement needs to be clear and specific regarding (1) duties
and procedures for snow and ice control, (2) responsibilities for communications
and control, and (3) contingencies. Contractors should be given a copy of those
31
The height of themarkers placed next
to edge lights should
be six inches outside
the propeller arc of
the most critical
airplane that uses the
airport.
Objective 15
AIM —Aeronautical
Information Manual
A NOTAM should be
issued when there is
more than one-half
inch of snow on
paved surfaces and
when a snow bank
exceeds 12 inches.
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portions of the ACM that apply to them, such as the snow plan and ground
vehicle operations. In addition, all airport leases and agreements should cover the
duties and responsibilities of lessees to carry out their snow and ice control
duties. It remains the responsibility of airport management to monitor all con-
tractor activities.
Airport Condition Reporting
Airport management is responsible for the timely notification of airport users
and the FAA of any conditions adversely affecting operational safety at the
airport. Several sections of Part 139 regulations require airport management to
have a system in place that will expediently notify users of any condition that is
not up to standard or that can affect aircraft operations. Airport management is
required to report deficient airport conditions, which could have an immediate
and critical impact on the safety of aircraft operations. Should it happen that
some element of Part 139 is not met, or an unsafe condition exists on the airport,air carrier activity for that area must be halted.
Notices to Airman (NOTAM)
The primary system used to convey safety information to airport users is known
as the Notice to Airman (NOTAM). The purpose of the NOTAM system is to
disseminate information on unanticipated or temporary changes to components
of, or hazards in, the National Airspace System until associated aeronautical
charts and other related publications can be amended.
The NOTAM system is important because airport operators have a duty to notifyusers of any change in published airport procedures or changes in the physical
facility. As an example, an airport manager should give timely and proper notice
of pavement or visual aids, which may have been damaged by a snowplow. If
the full width of a runway cannot be cleared of snow, the situation should be
reported in a NOTAM by giving details of the cleared width. This information
then allows each aircraft operator to judge the suitability of conducting opera-
tions since aircraft requirements differ.
The NOTAM system is not intended to be used to impose restrictions on airport
access for the purpose of controlling or managing noise, or to advertise data
already published or charted. NOTAM processing and dissemination are the
responsibility of FAA Flight Service Stations (FSS). When corrective actions
have been taken at the airport, the NOTAM should be canceled. The National
Flight Data Center (NFDC) in Washington, D. C. has overall management
responsibilities for the NOTAM system. At certain airports NOTAM issuance
may occur through the FAA air traffic control tower. However, airport manage-
ment is responsible for condition reporting and in these cases a letter-of-agree-
ment should be entered into, outlining the responsibilities for the NOTAM
issuance and dissemination.
The NOTAM system
is not intended to be
used to impose
restrictions on airport
access for the
purpose of control-ling or managing
noise, or to advertise
data already pub-
lished or charted.
The FAA Flight
Service Station (FSS)
is the processing
agency for NOTAM.
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NOTAMs cover a variety of topic areas that fall under one of the following: move-
ment areas, lighting aids, air navigation aids, communications, services, special data,
and Flight Data Center NOTAMs. It is airport management’s responsibility to
promptly distribute information about any condition on or near the airport that
would prevent, restrict, or otherwise present a hazard to arriving and departing
aircraft. NOTAMs are often not the complete solution to providing adequate notifi-
cation at a particular airport. An internal communications system such as telephone,
computer, facsimile, or hand-carried written method that directly notifies air carrier
offices and tenants can be more timely and efficient.
Two types of NOTAM dissemination exist for airport condition reporting. A
NOTAM (L) is disseminated locally by the FSS to the area affected by the
hazard, aid, or service being advertised. A user of the airspace system may
become aware of a NOTAM (L) existence only by calling the FSS that has
jurisdiction for the issuing airport. A NOTAM (D) is one that carries distant
(national) dissemination by the FSS, thereby allowing someone outside the local
FSS area to become aware of the NOTAM without specifically requesting it.
If an airport is listed in the Airport Facility/Directory (AF/D), either of the NOTAM
dissemination methods can occur depending on the facility, equipment, or condition
being reported, though exceptions do exist. Generally, conditions qualifying for
NOTAM (L) dissemination are those associated with (1) runway and taxiway
information that does not restrict or preclude their use, (2) personnel and equipment
on or adjacent to the runway or taxiways, or (3) taxiway edge lights.
NOTAM (D) is issued in cases of an airport closure or the presence of conditions that
restrict or preclude the use of any portion of a runway or waterway. These can
include runway braking action reports; existence of runway contamination such as
snow, ice, slush, standing water, or rubber accumulation; changes in friction measur-ing values; friction measuring equipment out of order; restrictions or permanent
changes to Aircraft Rescue and Firefighting (ARFF) index; and outages of various
airport lighting and navigation aids, especially obstruction lighting outages.
Specific to snow or icing conditions, a NOTAM should include information on the
type of contaminant (wet snow, dry snow, slush), the depth of contaminant, whether
full or partial coverage; snow banks exceeding height standards, pavement tempera-
ture (if a SSI system is in place), type of device used and friction measurement
readings, braking action reports, chemical or abrasive treatments, runway closure
times, and obscuration of lights or markings. When issued, a NOTAM will includethe following information:
1. Identification of the affected airport facility and component;
2. Description of the affected component condition, which prompted the NOTAM;
3. The effective time period the component will be affected;
4. Name, address, and phone number of the person issuing the NOTAM;
5. To whom copies are distributed;
33
A letter-of-agreement
outlining the responsi-
bilities for the
NOTAM issuance and
dissemination should
be entered into by an
airport and the FAA
air traffic control
tower when the latter
is involved in
NOTAM issuance.
Two types of NOTAM
dissemination—
NOTAM (L) and
NOTAM (D)
NOTAM (D) is
issued in cases of an
airport closure or the
presence of conditions
that restrict or
preclude the use of
any portion of a
runway or waterway.
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When reporting friction measurements, airport managers are to convey the runway
identifier, the type of device used, followed by the Mu number for each of the three run-
way segments, time of report, and a word describing the cause of the runway friction
problem. An example of a Mu report in the format used by ATC is as follows: “Runway
two seven, type of CFME, Mu 39, 37, 38 at one zero one eight Zulu, de-iced.”
Airports, certificated under FAR Part 139, must describe NOTAM issuance proce-
dures and required documentation in the ACM. Documentation of compliance is
necessary. A NOTAM log is required so that a manager can quickly access those
NOTAMs that are in effect and those that are not. When the FAA issues the
NOTAM, the time and duration of a NOTAM issuance is noted in Universal Time
Coordinated (UTC). The UTC system is stated in 10 digits (year, month, day, hour,
and minute). UTC replaced Greenwich Mean Time (GMT) in 1985. The acronym
ZULU continues in use, however, and it now represents the UTC date-time groups.
All times are expressed in the 24-hour clock. It is important that an airport document
the individual at the FAA facility who accepted the NOTAM information.
Airport Construction Activity
Periods of construction and maintenance on an airport present special prob-
lems in keeping aircraft, construction machinery, and personnel safely apart.
Obtaining contractor cooperation in this matter at the beginning is much
easier than trying to catch up later. The marking and lighting of construction
areas need to be spelled out clearly in the contract for incorporation into the
bid requirements. Planning for construction projects should always include
avoidance of damage to utilities.
Each bidding document (construction plans and/or specifications) for airportdevelopment work or NAVAlD installation involving aircraft operational areas
should incorporate an Airport Construction Safety Plan for the project. Con-
struction activities on an airport that are close to, or that affect aircraft opera-
tional areas or navigable airspace, are required to be coordinated with the FAA
and airport users before activities begin. Construction areas located within
safety areas require special attention in the project plans. Safety area encroach-
ments, improper ground vehicle operations, and unmarked or uncovered holes
and trenches near aircraft operating surfaces are the three most recurring threats
to safety during construction. Airport management is required to closely moni-
tor construction activity throughout its duration to ensure continual compliance
with safety requirements.
Certain airport projects, such as the construction, realigning, altering, activating,
or abandoning of a runway, landing strip, or associated taxiway, or construction,
or alteration of objects that affect navigable airspace, require formal written
notification to the FAA. On all AIP or PFC funded airport projects, a safety plan
must be developed. Key to the safety plan is the training of contractors and their
employees on how to operate safely on the airport.
Objective 15
The time and duration
of a NOTAM—noted
in Universal Time
Coordinated (UTC),
which replaced
Greenwich Mean
Time (GMT) in 1985
ZULU—represents
the UTC date-time
groups
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Pedestrians and Ground Vehicles
Vehicular activity on airport movement areas should be kept to a minimum.
Airport Movement Areas (AMA) are the runways, taxiways, and other areas of
an airport which are used for taxiing or hover taxiing, air taxiing, takeoff, and
landing of air carrier aircraft, exclusive of loading ramps and aircraft parking
areas. Where vehicular traffic on movement areas cannot be avoided, it shouldbe carefully controlled. A basic guiding principle is that the aircraft always has
the right-of-way. At certificated airports, vehicle access to the AMA must be
controlled and identified easily. This includes vehicle markings, key or code
access, two-way radio communication, signal lights, traffic signs, flagmen,
escorts, or other means suitable for each particular airport.
The control of pedestrian and vehicular activity on airport operations areas is of high
importance. Airport management is required to establish and implement procedures
for access to, and operation on, movement areas and safety areas by both pedestrians
and vehicles. To heighten awareness of this safety issue and minimize runway
incursions and surface incidents, FAA requires an airport operator to provide spe-cific training on these operational procedures and requires that individual training
records be kept. The training requirements apply to airport employees, tenant
employees, construction crews, vendors and contractors.
With respect to vehicular traffic, aircraft safety is likely to be endangered by
four principle causes: increased traffic volume, non-standard vehicle traffic
patterns, vehicles without radio communication and markings, and operators
untrained in the airport’s procedures.
Public Protection
The requirements of Part 139 pertaining to public protection are oriented toward
inadvertent entry by persons or vehicles onto the AOA and the hazards that
exist. The prevention of intentional infiltration of airport security areas is within
the purview of the regulation on airport security, (Transportation Security
Administration—TSA) Part 1542. The ACM should provide for surveillance of
all of the safeguards on the airport for compliance with this provision.
Airport design requires the consideration of jet blast when locating facilities and
forming operational areas. The forces of jet blast far exceed the forces of prop
wash due to the high velocities of jet exhaust. In terminal, maintenance, and
cargo areas, personnel safety is the overriding consideration in design. The jet
exhaust velocities of most turbofan and turbojet engines can exceed 100 m.p.h.
for distances up to 200 feet behind an aircraft trying to break away from a
standstill. To mitigate the effects of jet blast on personnel safety, including
vehicular traffic near runway and taxiways, blast fences are used to deflect the
jet exhaust.
35
TSAR Part 1542—
contains stipulations
for prevention of
intentional infiltration
of airport security
areas.
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Wildlife Hazard Management
Estimates by the FAA indicate that the economic cost from bird strikes are signifi-
cant— exceeding 400,000 hours of aircraft downtime and $216 million in direct
losses. Though bird strikes have been reported as high as 25,000 feet, the vast
majority of wildlife strikes occur below 600 feet above ground level. Birds are not
the only problem at airports. Other types of wildlife exist, including domesticanimals. For airports, wildlife includes mammals, birds, and reptiles, which exist
free in nature, and any domestic animals that are out of the control of their owners.
Wildlife becomes a hazard when the potential exists for a damaging aircraft collision
on or near the airport, or when certain conditions exist that can serve as an attraction
to wildlife that could pose an aircraft strike potential.
FAR Part 139 requires airport managers to show that they have established
instructions and procedures for the prevention or removal of factors on the
airport that attract—or might attract—wildlife. A wildlife attractant is consid-
ered to be any man-made structure, land-use practice, or natural geographic
feature that can attract or sustain hazardous wildlife within the landing ordeparture airspace, aircraft movement area, loading ramps, or aircraft parking
areas of an airport. These attractants can include, but are not limited to, architec-
tural features, landscaping, waste disposal sites, wastewater treatment facilities,
agricultural or aqua cultural activities, surface mining, or wetlands.
Part 139 requires airport management to conduct a Wildlife Hazard Assessment
when any of the following events occur on or near the airport:
1. An air carrier aircraft experiences multiple bird strikes.
2. An air carrier aircraft experiences substantial damage from striking wildlife.3. An air carrier aircraft experiences an engine ingestion of wildlife.
4. Wildlife of a size or in numbers capable of causing an accident event is ob
served to have access to any airport flight pattern or aircraft movement area.
A Wildlife Hazard Assessment must be conducted by a wildlife damage man-
agement biologist who has professional training and/or experience in wildlife
hazard management at airports or an individual working under the direct super-
vision of such an individual.
FAA Form 5200-7, Bird Strike Incident/Ingestion Report, is used to report
bird strikes to the FAA. It is available in the Aeronautical InformationManual (AIM), from a Flight Service Station (FSS) or from the FAA Air-
ports District Office (ADO). The form is also used to report other types of
wildlife collisions or incidents.
A Wildlife Hazard Assessment consists of (1) analyzing the events or circumstances
that prompted the research; (2) identifying the species, numbers, locations, local
movements, and daily and seasonal occurrences of wildlife observed; (3) identifying
and locating features on and near the airport that attract wildlife; (4) describing the
36
FAR Part 139 requires
airport managers to
show that they have
established instructions
and procedures for the
prevention or removal
of factors on the air-
port that attract—or
might attract—wildlife.
A wildlife attractant—
any man-made
structure, land-use
practice, or natural
geographic feature that
can attract of sustain
hazardous wildlife
Objective 16
An assessment of wildlife hazard is
required when any of
the following events
occur on or near the
airport: (1) an air
carrier aircraft
experiences multiple
bird strikes, (2) an air
carrier aircraft
experiences substantial
damage from striking
wildlife, (3) an air
carrier aircraft
experiences an engine
ingestion of wildlife,
and (4) wildlife of a
size or in numbers
capable of causing an
accident event is
observed to have
access to any airport
flight pattern or aircraft
movement area.
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wildlife hazard to air carrier operations; and (5) recommended actions for reducing
the identified hazards on air carrier operations.
Upon completion the Wildlife Hazard Assessment, the document must be
submitted to the FAA Administrator for approval and a determination if a
Wildlife Hazard Management Plan is needed.
In addressing wildlife hazards at a certificated airport, one of three types of
entries is needed in the ACM: (1) a statement of negative activity; (2) a brief
statement of the no-hazard findings of a Wildlife Hazard Assessment; or (3)
a Wildlife Hazard Management Plan. In any event, the ACM should contain
instructions for reporting observed wildlife activity. If no wildlife activity
exists or none that triggers the Wildlife Hazard Assessment, a statement to
that effect must be recorded in the ACM. If it has been determined that an
airport must have a Wildlife Hazard Management Plan, it then becomes a
permanent part of the ACM.
Two other requirements are placed on the airport operator if a Wildlife HazardManagement Plan is mandated by FAA. The first is that a training program must be
conducted for airport personnel involved in wildlife management by a qualified
wildlife damage management biologist in order to provide these individuals with the
knowledge and skills needed to successfully carry out the Plan. Secondly, the
Wildlife Hazard Management Plan must be reviewed and evaluated annually.
The basic ingredient in an effective wildlife control program is not the tech-
niques used, but rather the abilities of airport personnel and the support of
management. Wildlife control is based primarily on two approaches: (1) habitat
modification and (2) active control. Active control includes scaring, dispersal,
trapping, and lethal control. Since birds are the primary hazard to aircraft,reducing the potential for bird strikes at airports involves one or more strategies.
Elimination of a food source and habitat modification are the primary method.
Habitat management is a planned activity, which begins with the identification
of habitat, consideration of alternatives for modification or elimination of the
habitat, and then the incorporation of changes into a long-term land-use man-
agement practice.
Habitat modification may require keeping grass at 10-14 inches for gulls, or 6
inches for other birds of prey. It could require removing trees, ponds, building
ledges, and other unnecessary perches and roosting areas. Other means forminimizing wildlife interference may include (1) installing at least a ten-foot
perimeter fence with barbed wire to prevent wandering wildlife, (2) placing
glycol storage basins and storm water ponds underground or providing netting
over them to keep birds out, (3) draining all standing water areas, (4) designing
ponds with a 4: 1 slope, and (5) using sweepers to remove worms from airport
hard surfaces.
FAA Form 5200-7,
Bird Strike Incident/
Ingestion Report, is
used to report to the
FAA not only bird
strikes but also other
types of wildlife
collisions or incidents.
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Secondary strategies involve the active control of the birds through harassing
or frightening techniques and lethal control. These methods can be bird
distress call tapes, pyrotechnic devices, propane cannons, whistles, decoys,
shotgun blasts with screamers shells, high pressure water from fire hoses,
and even papier-mâché owls to frighten birds. There is also the use of
chemical treatment to cause dispersal and movement of flocks. Lethal con-
trol or the killing of wildlife through the use of chemicals, firearms or other
mechanical means normally requires a depredation permit from a state or
federal Fish and Wildlife Service. Since birds and animals adapt to the
various strategies, effective wildlife control requires continuous changes to
the method used.
Large numbers of wildlife that are hazardous to aircraft are known to be
attracted to such things as waste disposal operations, waste water treatment
facilities, settling ponds, and artificial marshes. When located within certain
distances of the airport, they are considered incompatible with safe airport
operations. Accordingly, measures to minimize hazardous wildlife attraction
should be developed.
The Environmental Protection Agency (EPA) requires any operator proposing a
new or expanded waste disposal operation within five statute miles of a runway-
end to notify the appropriate FAA Regional Airports District Office and the
airport operator of the proposal. The EPA also requires owners or operators of
new Municipal Solid Waste Landfill (MSWLF) units—or lateral expansions of
existing MSWLF units that are located within 10,000 feet of any airport run-
way-end used by turbine powered aircraft or within 5,000 feet of any airport
runway-end used only by piston-type aircraft—to demonstrate successfully that
such units are not hazards to aircraft.
The FAA recommends that, to the extent practicable, operators of AIP funded
airports oppose off-airport land-use changes or practices within the distances
noted above that may attract hazardous wildlife. Failure to do so could place the
airport in noncompliance with applicable grant assurances. It is the responsibil-
ity of airport operators, sponsors, planners, and land-use developers to consider
whether any proposed land uses, including new airport development projects,
would increase the wildlife hazard. Because grant assurances and certification
are affected, AIP funds can be used for wildlife control.
All species of wildlife can pose a threat to aircraft safety. However, some spe-cies are more commonly involved in aircraft strikes than others. Gulls, water-
fowl, raptors, doves, vultures, blackbirds/starlings, corvids, wading birds, and
deer are the most common wildlife groups reported as being involved in damag-
ing strikes to aircraft in the United States.
Airports often experience other localized wildlife problems with diverse animals
such as cows, armadillos, rabbits, alligators, moose, prairie dogs, coyotes, and
groundhogs. Because the wildlife species and the size of the populations at-
MSWLF—Municipal
Solid Waste Landfill
AIP funds can be used
for wildlife control.
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tracted to the airport environment are highly variable, it is important for airport
management to identify those land-use practices in the airport area that serve to
attract any such hazardous wildlife. The U. S. Department of Agriculture
(USDA) has expertise in the management of wildlife problems. The Wildlife
Services Department of the USDA can provide assessments and advice for
dealing with wildlife problems and control.
Airport operators with wetlands located on or near airport property should be
alert to any wildlife use or habitat changes that could affect safe aircraft opera-
tions. When expanding existing airports in or near wetlands, the wildlife hazards
should be evaluated and minimized through a wildlife management plan. The U.
S. Fish and Wildlife Service (USFWS) and the U. S. Army Corps of Engineers
(COE) can assist and make a determination as to whether or not an area would
qualify as a wetland.
The movement of storm water away from runways, taxiways, and aprons is a
normal function on most airports and is necessary for safe aircraft operations.
Both detention and retention ponds are used for the purpose of controllingrunoff and protecting water quality. Detention ponds hold storm water for short
periods (typically three hours or less), while retention ponds hold water
indefinitely. They both can attract hazardous wildlife. Retention ponds are
more attractive to hazardous wildlife than detention ponds because they
provide a more reliable water source. To facilitate hazardous wildlife con-
trol, the FAA recommends using steep-sided, narrow, linearly shaped,
riprap-lined, water detention basins rather than retention basins. When
possible, these ponds should be placed away from aircraft movement areas
to minimize aircraft-wildlife interactions. All vegetation that provides food
or cover for hazardous wildlife in or around detention or retention basins
should be eliminated.
Airport management often promote revenue-generating activities such as
agricultural crop production on airports. Any proposed on-airport agricul-
tural operations need to be carefully reviewed as to its attraction to wildlife
since such use may create potential hazards to aircraft by attracting wildlife.
If a problem with hazardous wildlife develops, an on-site inspection by the
USDA, Animal Damage Control or other qualified wildlife biologist should
be conducted. Regardless of the source of the attraction, prompt remedial
actions to protect aviation safety are recommended.
The key to effective wildlife control is not only detecting wildlife on the
airport but also anticipating its presence. It is important to pay attention to
weather, increased bird activities associated with migration, seasonal differ-
ences, and attractiveness of activities being performed on the airport. If an
existing land-use practice creates a wildlife hazard and the land- use practice
or wildlife hazard cannot be immediately eliminated, airport management is
obligated to issue a NOTAM and encourage the land owner or manager to
take steps to control the wildlife hazard and minimize further attraction. If
To facilitate hazardous
wildlife control, the
FAA recommendsusing steep-sided,
narrow, linearly
shaped, riprap-lined,
water detention basins
rather than retention
basins.
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Key to effective
wildlife control—
detecting wildlife and
anticipating its
presence
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the condition is expected to last indefinitely, the NOTAM can become a
permanent record within the Airport/Facility Directory. Such an entry in the
A/FD needs to be accompanied by a Wildlife Hazard Assessment.
Summary
Airport Operations is at the heart of an airport’s dynamic environment. In
that capacity, the operators of all federally certificated airports are required
to meet minimum safety standards required or prescribed by Part 139 of the
Federal Aviation Regulations (FAR), Certification of Airports. To accom-
plish this task of operating the airport in a safe and efficient manner, airport
operating departments are required to develop an Airport Certification
Manual (ACM). The ACM covers key airport operational issues and de-
scribes how the airport intends to comply with the statutory requirements of
FAR Part 139.
The central theme and purpose of the ACM is to be a useful working docu-ment, to help personnel maintain a safe airport, and complying with the
regulations. The most critical element to ensure safe operations is regular
self-inspections of the airport in order to identify those conditions that are
hazards or have the potential to become hazards. Establishing procedures to
correct deficiencies noted during the inspections is also the responsibility of
the operating departments.
Because of the day-to-day attention to details by personnel in Airport Opera-
tions, the United States airports are a major component of the safest aviation
system in the world.
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Appendix A: Standard for Airport Sign System
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Appendix B: ACM Elements - Section 139.203(B)
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Study Questions
1. What are the changes in certification requirements under the most recentFAR Part 139?
2. How are the four classes of airports defined in the most recent
FAR Part 139?
3. What is the purpose of an airport certification manual (ACM)? What doesit provide? What does it emphasize?
4. What are the key components that an airport self-inspection program?What type of activities do these components address?
5. What affects pavement strength and wear? How does poor pavementaffect aircraft? How can traction and friction be maintained and improved?
6. What are the major causes of pavement deterioration? How can
deterioration be mitigated?
7. How are pavement conditions measured? What is the effect of differentreadings?
8. What are airport movement and safety areas? What criteria affect them?
9. What types of approach lighting systems exist? What are their operatingcriteria?
10. What are the marking and signage requirements at airports? Whatinscriptions and colors are used for markings and signs?
11. How do snow and ice affect pavement surface? What responsibility doesairport management have to mitigate the effects?
12. Why is it important to have a snow and ice plan? What does such a planconsist of?
13. What are the various methods for removing snow and ice from pavementsurfaces?
14. What are the basic properties of anti-ice and de-ice compounds?
15. What does NOTAM mean? When should a NOTAM be issued? Whatinformation does a NOTAM convey?
16. When should a Wildlife Hazard Assessment at an airport be conducted?What should such a study contain?