The document discusses taxiway design at airports, highlighting their role in connecting key facilities and optimizing aerodrome efficiency. It describes various types of taxiways, geometric standards, and factors influencing their layout, such as safety, capacity, and aircraft movement. Key features include the design of exit and rapid exit taxiways to minimize runway occupancy and enhance operational efficiency.

1. Chapter 2
Taxiway Design

3. Taxiway
• A Taxiway is a path for aircraft at an airport connecting runways with
aprons, hangars, terminals and other facilities.
• They mostly have a hard surface such as asphalt or concrete, although
smaller general aviation airports sometimes use gravel or grass.
• Maximum capacity and efficiency of an aerodrome are realized only
by obtaining the proper balance between the need for runways,
passenger and cargo terminals, and aircraft storage and servicing
areas. These separate and distinct aerodrome functional elements are
linked by the taxiway system.

4. Taxiway (Contd…)
• The components of the taxiway system therefore serve to link the
aerodrome functions and are necessary to develop optimum
aerodrome utilization.
• The taxiway system should be designed to minimize the restriction of
aircraft movement to and from the runways and apron areas.

5. Taxiway (Contd…)
• A properly designed system should be capable of maintaining a
smooth, continuous flow of aircraft ground traffic at the maximum
practical speed with a minimum of acceleration or deceleration.
• This requirement ensures that the taxiway system will operate at the
highest levels of both safety and efficiency.

6. Factors controlling layout of taxiway
1. Arrangement: Aircraft which has just landed should not interfere
with the aircraft taxiing to take-off.
2. Busy Airport: Exit taxiway should be provided at various points.
Parallel one way taxiway should be provided.
3. Crossing: Intersection of runway and taxiway should be avoided.
4. Route: Route should be so selected that it provides shortest
practicable distance.

7. Types of taxiways
1. Parallel taxiway
➢Provided parallel to an adjacent runway.
➢It facilitates aircrafts to reach the apron from runway after landing and from
apron to runway for take-off.
2. Entrance taxiway
➢Located near the runway threshold.
➢It facilitates entry of an aircraft to runway for take-off operation.

8. Types of taxiways (Contd…)
3. Exit taxiway.
➢Located at various points along the runway to allow landing aircraft to
efficiently exit the runway after landing.
4. Bypass taxiway
➢Provided to give way to other aircraft.
➢Located at areas of congestion at busy airports.

10. Fig.: Bypass Taxiway

11. Geometric Design Standards of Taxiway
• Length of the taxiway should be as short as practicable.
• No specific guideline is available for length of taxiway.
• Other features like width, separation distance, longitudinal slope etc.
as per ICAO is given in table

14. Taxiway Width
• Depending on the code letter of the runway, minimum margins of
safety between 1.5m to 4.5m should be provided between outer
main gear wheel edge and the taxiway edge.
• Width of taxiway is less than the width of corresponding runway
because aircraft taxi speed is considerably slower than the speed of
aircraft during take-off or landing.
• The taxiway width needs to be between 7.5m (code letter A) to 25m
(code letter F).

15. Taxiway Width (Contd…)

16. Taxiway curves
• Changes in direction of taxiways should be as few and small as
possible.
• The radii of the curves should be compatible with the maneuvering
capability and normal taxiing speeds of the aircrafts for which the
taxiway is intended.
• Taxiway need to be widened with extra width where they have sharp
curves so that the necessary safe separation distance between the
outer main gear wheel edge and runway edge may be maintained.

18. Turning Radius of Taxiway
• Change in aircraft path is done by providing a horizontal curve.
• Design should be such that the aircraft can negotiate the curve
without significantly reducing the speed.
• Relationship between exit speed and radius of curve (turning radius)
Radius (m) =
𝑉2
125 𝑓
Where, V is in kmph
f is coefficient of friction between aircraft wheel tyre and
taxiway pavement and is equal to 0.13

19. Exit Taxiway
• The function of exit taxiway is to minimize runway occupancy by
landing aircrafts.
Location of Exit taxiway
• The location of exit taxiway depends on the following points:
i. Mix of aircraft
ii. Approach and touchdown speed
iii. Point of touchdown
iv. Exit speed
v. Rate of deceleration
vi. Pavement condition
vii. Air traffic control

21. Rapid Exit Taxiways
• A rapid exit taxiway is a taxiway connected to a runway at an acute
angle and designed to allow landing aircrafts to turn off at higher
speeds than those achieved on other exit taxiways, thereby
minimizing runway occupancy time.
• A decision to design and construct a rapid exit taxiway is based upon
analyses of existing and expected/planned air traffic.

22. Rapid Exit Taxiways (Contd…)
• The main purpose of these taxiways is to minimize aircraft runway
occupancy and thus increase airport capacity.
• When the design peak hour traffic density is approximately less than
25 operations (landings and take-offs), the right angle exit taxiway
may be sufficient.
• The construction of this right angle exit taxiway is less expensive, and
when properly located along the runway, it achieves an efficient flow
of traffic.

23. Fig: Rapid Exit Taxiway

24. Numerical Examples
# What shall be the radius of an exit taxiway with design exit speed of
90 kmph and coefficient of friction 0.13? (Answer: 500 m)
# Consider the following data for designing a taxiway for operating
Boeing 707-320 airplane:
Wheel base = 17.70 m
Thread of main loading gear = 6.62 m
Turning speed = 40 km/hr.
Coefficient of friction between tyres and pavement surface = 0.13
What will be the turning radius of the taxiway? (Answer: 98.5 m)

25. Taxiway Separation
• The minimum safe separation distance between the center-line of a taxiway and
the center-line of a runway is defined as a standard in Annex 14, Aerodrome
Design and Operation, Volume I.

26. Taxiway Separation (Contd…)
• The separation requirement between parallel taxiways is based on
the wingtip clearance requirement when an aircraft has deviated
from the taxiway centerline.

27. Taxiway Separation (Contd…)
• The formula for the separation distance in this case is:
S = WS + C + Z
Where, WS = wingspan
C = the clearance between the outer main gear wheel and the
taxiway edge (maximum allowable lateral deviation) and
Z = wingtip clearance.

28. Holding Apron
• Holding aprons, holding pads, run-up pads, or holding bays as they
are sometimes called, are placed adjacent to the ends of runways.
• The defined areas that are used as storage areas for aircraft prior to
takeoff until the runway is clear for takeoff are called Holding Apron.
• They are designed so that one aircraft can bypass another whenever
this is necessary.
• They are provided where traffic volume are high.

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