Airport Engineering

Some Basic Definitions:
1. Aircraft: “Any machine which finds its support in the atmosphere due
to reactions of the air is defined as an Aircraft”.
It is a general term which includes aero-plane, helicopter, rocket, etc. It
may be lighter or heavier than air.
a) subsonic aircraft- Aircraft speed is less than the speed of sound
b) supersonic aircraft- Aircraft speed is greater than the speed of sound.
2. Aerodrome: Any defined area on land or water intended to be used for the
arrival and departure of an aircraft is called aerodrome.
3. Airport: It is an aerodrome which is principally intended for the use of
commercial services. It is provided with custom facilities. If it service any
international traffic. i.e if it is designed as an international airport. When an
airport does not serve international traffic, it is known as non-international
or domestic airport.
4. Airfield: it is an area which is used for landing and take-off of an aircraft.

5)Landing area: An airport consists of landing area and terminal area. Landing
area is used for landing & take-off of an aircraft.
1) Runway
2) Taxiway
6) Terminal area: It includes the following
a) Terminal building
b) Aircraft apron
c) Gate position
d) Hangars (Shelters)
e) Automobile parking area
7) Runway: It is paved long & narrow rectangular strip which is actually used
for landing & take-off of aero-planes.
8) Taxiway: It is a paved way over which an aero-plane may taxi while going
to & from runway and loading apron. Taxiways also connect two
neighboring runway, runway with a service and maintenance hangar.

Airport Classification
• International Airports
• Custom Airports
• Model Airports
• Other Domestic Airports
• Civil Enclaves in Defence Airport

SITE SELECTION
The emphasis in airport planning is normally on the expansion and
improvement of existing airports. However if an existing airport cannot
be expanded to meet the future demand or the need for a new airport is
identified in an airport system plan, a process to select a new airport site
may be required.
• Identification
• Screening
• Operational capability
• Capacity potential
• Ground access
• Development costs
• Environmental consequences
• Compatibility with area-wide planning
• Readily accessible to the users
• Natural protection from air-raids

AIRPORT MASTER PLAN
• An airport master plan is a concept of the ultimate development of
a specific airport.
• The term development includes the entire airport area, both for
aviation and non-aviation uses, and the use of land adjacent to the
airport. It presents the development concept graphically and
contains the data and rationale upon which the plan is based.
• Master plans are prepared to support expansion and modernization
of existing airports and guide the development of new airports.
• The overall objective of the airport master plan is to provide
guidelines for future development which will satisfy aviation
demand in a financially feasible manner and be compatible with the
environment, community development, and other modes of
transportation.

AIRCRAFT
CHARACTERISTICS
• Type of propulsion of aircraft
• Size of aircraft
• Minimum turning radius
• Minimum circling radius
• Speed of the aircraft
• Aircraft capacity
• Weight of aircraft and wheel configuration
• Jet blast
• Fuel Spillage
• Noise

Important Components of An
Airport Layout
• Runway
• Terminal Building
• Apron
• Taxiway
• Aircraft Stand
• Hanger
• Control Tower
• Parking

RUNWAY
A runway is a rectangular area on the airport surface
prepared for the takeoff and landing of aircraft. An
airport may have one runway or several runways
which are sited, oriented, and configured in a
manner to provide for the safe and efficient use of
the airport under a variety of conditions. Several of
the factors which affect the location, orientation,
and number of runways at an airport include local
weather conditions, particularly wind distribution
and visibility, the topography of the airport and
surrounding area, the type and amount of air traffic
to be serviced at the airport, aircraft performance
requirements, and aircraft noise.

Runway Configurations
-Theterm runway configuration refers to the number and
relative orientations of one or more runways on
an airfield.
combinations of several basic
The basic configurations are
• Single runways
• Parallel runways
• Intersecting runways
• Open-V runways
-Many runway configurationsexist. Most
configurations are
configurations.

Runway orientation
Runway is usually oriented in the direction of
the prevailing winds. The head wind i.e. The
direction of wind opposite to the direction of
landing and take-off, provides greater lift on
the wings of the aircraft when it is taking off.

FACTORS AFFECTING RUNWAY
ORIENTATION
• WIND
• AIRSPACE AVAILABILITY
• ENVIRONMENTAL FACTORS
• OBSTRUCTIONS TO NAVIGATION
• AIR TRAFFIC CONTROL VISIBILITY
• WILD LIFE HAZARDS
• TERRAIN AND SOIL CONSIDERATION

Wind direction indicator
• It may be a wind cone, usually placed at the centre
of the segmented circle marker. This helps the pilot
in locating the airport and the wind direction
indicator. The panel forming the segmented circle
markers are gable roof shaped with a pitch of at
least 1 to 1. this enhances the visibility of the
segmented circle and the pilot will be able to detect
it from a considerable distance ahead. In most of
the cases, the panels are painted white so as to
obtain a distinctive colour contrast between the
marker and its surroundings and to protect them
against weather.

Wind rose
• The wind data i.e. Direction, duration and
intensity are graphically represented by a
diagram called wind rose.
• The data should usually be collected for a period
of at least 5 years and preferably of 10 years, so
as to obtain an average data with sufficient
accuracy.
• Wind rose diagrams can be plotted in two types
1. showing direction and duration of wind
2.Showing direction duration and intensity of
wind.

• Type – I: This type of wind rose is illustrated in fig. the radial lines indicate
the wind direction and each circle represents the duration of wind. The
values are plotted along the north direction in fig similarly other values
are also plotted along the respective directions. All plotted points are
then joined by straight lines.
• The best direction of runway is usually along the direction of the longest
lone on wind rose diagram. If deviation of wind direction up to 22.5º +
11.25ºfrom their direction of runway is thus along NS direction of landing
and take off is permissible the percentage of time in a year during which
runway can safely be used for landing and take off will be obtained by
summing the percentages of time along NNW, N, NNE, SSE, S and SSW
directions. This comes to 57.6 percent. The total percentage of the time
therefore comes to 57.0 + 13.5 = 70.5. This type of wind rose does not
account for the effect of cross wind component.

• Type – II : this type of wind rose is illustrated in fig. the wind data as in the
previous type is used for this case. Each circle represents the wind
intensity to some scale. The values entered in each segment represent the
percentage of time in a year during which the wind having a particular
intensity blows from the respective direction. The procedure for
determining the orientation of runway from this type of wind rose is
described.
• Draw three equi spaced parallel lines on a transparent paper strip in such a
way that the distance between the two near by parallel lines is equal to
the permissible cross wind component. This distance is measured with the
same scale with which the wind rose diagram is drawn the permissible
cross wind component is 25kph. Place the transparent paper strip over the
wind rose diagram in such a way that the central line passes through the
centre of the diagram. With the centre of wind rose rotate the tracing
paper and place it in such a position that the sum of all the values
indicating the duration of wind within the two outer parallel lines is the
maximum. The runway should be thus oriented along the direction
indicated by the central line. The wind coverage can be calculated by
summing up all the percentages

Basic Runway Length
• The basic runway length is determined form the
airport. The following cases
performance characteristics of aircraft
are
using usually
considered Normal landing case, Normal takeoff
case, Engine failure case.
• Runway length is an important factor for
adequate aircraft performance and cost of airport
layout. The short range aircraft needs lesser
runway length than the long range type, since
there is a smaller fuel requirement.

Runway length A runway of at least 6,000 ft (1,800 m) in
length is usually adequate for aircraft weights below
approximately 200,000 lb (90,000 kg). Larger aircraft including
wide bodies will usually require at least 8,000 ft (2,400 m) at sea
level and somewhat more at higher Altitude airports. International
wide body flights, which carry substantial amounts of fuel and are
therefore heavier, may also have landing requirements of 10,000 ft
(3,000 m) or more and takeoff requirements of 13,000 ft (4,000
m).
At sea level , 10,000 ft (3,000 m) can be considered an
adequate length to land virtually any aircraft. An aircraft will need
a longer runway at a higher altitude due to decreased density of air
at higher altitudes, which reduces lift and engine power, requiring
higher take-off and landing speed Runway length
BASIC RUNWAY LENGTH

BASIC RUNWAY LENGTH, THE LENGTH IS
CALCULATED UNDER THE FOLLOWING
CONDITIONS:
• No wind blowing on the runway.
• Aircraft is loaded with full loading capacity.
• Airport is provided at the sea level
• No wind is blowing on the way to the destination
• The runway is levelled and it is provided with zero effective
gradient.
• The standard temperature is 15 degrees centigrade at the airport.

FACTOR AFFECTING BASIC
RUNWAY LENGTH
1. Aircraft Performance Characteristics.
2. Landing & Take–Off Gross Weights of the Aircraft.
3. Airport Elevation.
4. Maximum Temperature.
5. Runway Gradient.
6. Runway Surface Condition.

The very first thing which is going to create an effect is the power and the
prolusion system. Now, as we have seen that in the case of an aircraft which is
landing or which is taking off, the power is one of the important aspects which
create its effect or the propulsion system which is being provided is the one
which finally gets transformed into the power. So, here what we are
understanding is that if the power is more, then the aircraft requires a longer
length so as to stop, because it has, there is a certain rate of de-acceleration and
with that rate of de-acceleration, the vehicle or the aircraft will be going to stop.
AIRCRAFT CHARACTERISTICS

These gross take-off or gross landing weight of the aircraft has its effect at the time
when the aircraft is taking off or it is landing, respectively. Now, in this case what
happens is that, if there is a heavy take-off load, then obviously the aircraft will
require more of the power and so as to get more of this power, it has to run more
distance and by running that particular more distance.
It will be reaching that velocity at which there will be a possibility of
attaining the lift or the lift becomes more than the weight, which is otherwise acting
in the downward direction. So, if that condition is achieved, then only the aircraft
will be going into air. So, that is the effect of the take-off load for the aircraft and in
case of runway length, there will be more length required if there is a higher take-off
gross weight.
LANDING & TAKE–OFF GROSS WEIGHTS OF THE AIRCRAFT

RUNWAY GEOMETRIC DESIGN
Geometric design of following runway elements
Runway length
Runway Width
Longitudinal gradient
Transverse gradient
Sight distance
Runway surface
Sunway shoulders
Runway strips
Runway end safety area
Clearway
Stop way

RUNWAY PATTERNS
The Basic runway pattern are
•Single runway
•Parallel runway
•Intersecting runway
•Non- Intersecting runway

This is the simplest of the runway configurations. Suitable when
winds predominantly blow along the runway and the peak
hour air traffic demand is less than 50 operations. When winds
are light both ends can be used for both arrivals and
departures. When winds are strong only one end can be used
for operations. The capacity of a single runway depends on air
traffic mix and type of control.
SINGLE RUNWAY

INTERSECTING RUNWAY
Intersecting Runway It becomes necessary to use this configuration when winds are
blowing in more than one direction. When the winds are light both runways can be used.
When the winds are strong only one runway can be used. Capacity depends on the location
of the intersection point and the runway-use-strategy. The farther the intersection is from
the takeoff end of the runway and the landing threshold, the lower is the capacity. Highest
capacity is achieved when the intersection is close to the takeoff end and the landing
threshold.

Correction for elevation, temperature
and gradient
• Airports are constructed in different elevation
different atmospheric temperature and gradient,
in contrast to the assumption made for basic
runway length. Therefore correction required for
changes in each components.

Correction in elevation
• All other things being equal, the higher the field
elevation of the airport, results the less dense the
atmosphere, requiring longer runway lengths for
the aircraft to get to the appropriate
groundspeed to achieve sufficient lift for takeoff.
For airports at elevation above sea level, the
design runway length is 300 ft plus 0.03 ft for
every foot above sea level. ICAO recommends the
basic runway length should increase at rate of 7%
per 100 m rise in elevation over MSL.

Correction in temperature
• With rise of reference temperature same effect is there as that of elevation. The
airport reference temperature defined as monthly mean of average daily
temperature (Ta) for the hottest month of the year plus one third the difference of
this temperature and monthly mean of the maximum daily temperature(Tw) for
same month of the year. Reference Temperature = Ta + (Tw – Ta)/3
• ICAO recommends the basic runway length after having been corrected for
elevation, should further increase at the rate of 1% for every 10C increase of
reference temperature. If each correction increases more than 35% ICAO
recommended specific site study should be conducted.
• The standard atmospheric temperature at the site can be determined by reducing
the standard sea level temperature of 150 C at the rate of 6.50 C per 1000 m rise in
elevation.

Correction for gradient
• Steeper gradient require greater consummation
of energy and longer length of runway to attain
the desired speed. ICAO does not recommend
any correction. FAA recommend after correction
for elevation and temperature a further increase
in runway length at arte of 20% for every 1
percent effective gradient. Effective gradient is
defined taking maximum difference between
elevation between lowest point and highest point
in the runway divided by length of the runway.

Actual length of Runway
• F.A.A. specifies a gradient correction of the rate of
20% of the length corrected for altitude &
temperature for each 1% of the effective runway
gradient. This is determined by dividing the
maximum difference in the runway centreline
elevation by the total length of runway.
• As per recommendation of ICAO under the
minimum clearances, 60m additional length on
either end of the runway should be graded. The
total length of landing strip therefore comes to
(L+120m) where L is the basic runway length.
• According to ICAO recommendations total
correction percentage for altitude and temperature
should not exceed 35%.

Runway geometrics
(ICAO)
Airport
Types
Basic Runway Length Runway
Pavement Width
Max.
longitudinal
grade %Maximum Minimum
m ft m ft m ft
A 2100 7000 45 150 1.5
B 2099 6999 1500 5000 45 150 1.5
C 1490 4999 900 3000 30 100 1.5
D 899 2999 750 2500 22.5 75 2.0
E 749 2499 600 2000 18 60 2.0

Taxiways
• Taxiways are defined paths on the airfield surface which are
established for the taxiing of aircraft and are intended to
provide a linkage between one part of the airfield and another.
Basically it established the connection between runway,
terminal building and hanger.
• The main function of the taxiway is to provide access to
aircrafts from the runway to the loading apron or service
hanger and back.
• Taxiways are arranges such that the aircraft which have just
landed and are taxiing towards the apron, do not interfere with
the aircrafts taxiing for take-off.
• At busy airports, these are located at various points along the
runways. As far as possible, the intersection of taxiway and
runway should be avoided.
• The taxiway route should be shortest possible distance to
minimise terminal delay.

Exit Taxiway
• The function of exit taxiways, or runway turnoffs
as they are sometimes called, is to minimize
runway occupancy by landing aircraft.
• Exit taxiways can be placed at right angles to the
runway or some other angle to the runway. When
the angle is on the order of 30°, the term high-
speed exit is often used to denote that it is
designed for higher speeds than other exit
taxiway configurations.

Location of Exit Taxiways
• The location of exit taxiways depends on the mix of aircraft, the
approach and touchdown speeds, the point of touchdown, the
exit speed, the rate of deceleration, which in turn depends on
the condition of the pavement surface, that is, dry or wet, and
the number of exits.
• While the rules for flying transport aircraft are relatively
precise, a certain amount of variability among pilots is bound to
occur especially in respect to braking force applied on the
runway and the distance from runway threshold to touchdown.
The rapidity and the manner in which air traffic control can
process arrivals is an extremely important factor in establishing
the location of exit taxiways.
• The location of exit taxiways is also influenced by the location of
the runways relative to the terminal area.

Holding Aprons
• Holding aprons, holding pads, run-up pads, or holding
bays as they are sometimes called, are placed adjacent
to the ends of runways.
• The areas are used as storage areas for aircraft prior to
takeoff. They are designed so that one aircraft can
bypass another whenever this is necessary.
• For piston-engine aircraft the holding apron is an area
where the aircraft instrument and engine operation can
be checked prior to takeoff.
• The holding apron also provides for a trailing aircraft to
bypass a leading aircraft in case the takeoff clearance of
the latter must be delayed for one reason or another, or
if it experiences some malfunction.

Hanger
• The primary function of hanger is to provide an
enclosure for servicing, over hauling and doing
repairs of the aircrafts.
• They are usually constructed of steel frames and
covered with G.I. sheets.
• They are also provided with machine shops and
stores for repair parts.
• The size of hanger depends upon the size of aircraft
and its turning radius. The number of hangers
depend upon the peak hour volume of aircrafts and
demand of hangers on rental basis by different
airline agencies.

Terminal building
• The terminal area is the major interface between the
airfield and the rest of the airport. It includes the facilities
for passenger and baggage processing, cargo handling, and
airport maintenance, operations, and administration
activities.
• The purpose of airport building or terminal building is to
provide shelter and space for various surface activities
related to the air transportation. As such they are planned
for maximum efficiency, convenience and economy.
• The extent of building area in relation to the landing area
depends upon the present and future anticipated use of
airport.

Aircraft parking
• Apron size and gate area are very much dependent
upon the manner in which aircrafts are parked, with
respect to terminal building and the manner aircrafts
manoeuvre in and out of parking position in the gate.
• Five basic aircraft parking patterns are as follows:
✓ Nose-in Parking
✓ Nose-out Parking
✓ Angle nose-in Parking
✓ Angle nose-out Parking
✓ Parallel Parking

AIRPORT MAKING AND LIGHTING
• Visual aids assist the pilot on approach to an airport,
as well as navigating around an airfield and are
essential elements of airport infrastructure.
• As such, these facilities require proper planning and
precise design. These facilities may be divided into
three categories: lighting, marking, and signage.

Approach lighting or surface lighting
Specific lighting systems include:
• Approach lighting
• Runway threshold lighting
• Runway edge lighting
• Runway centerline and touchdown zone
lights
• Runway approach slope indicators
• Taxiway edge and centerline lighting

Obstruction Lighting
• Obstructions are identified by fixed,
flashing, or rotating red lights or beacons.
All structures that constitute a hazard to
aircraft in flight or during landing or takeoff
are marked by obstruction lights having a
horizontally uniform intensity duration and
a vertical distribution design to give
maximum range at the lower angles (1.5°
to 8°) from which a colliding approach
would most likely come

Approach Lighting
• Approach lighting systems (ALS) are designed
specifically to provide guidance for aircraft
approaching a particular runway under night
time or other low-visibility conditions. While
under night time conditions it may be possible
to view approach lighting systems from
several miles away, under other low-visibility
conditions, such as fog, even the most intense
ALS systems may only be visible from as little
as 2500 ft from the runway threshold.

Threshold Lighting
• During the final approach for landing, pilots must make
a decision to complete the landing or execute a missed
approach. The identification of the threshold is a major
factor in pilot decisions to land or not to land. For this
reason, the region near the threshold is given special
lighting consideration. The threshold is identified at
large airports by a complete line of green lights
extending across the entire width of the runway, and at
small airports by four green lights on each side of the
threshold. The lights on either side of the runway
threshold may be elevated. Threshold lights in the
direction of landing are green but in the opposite
direction these lights are red to indicate the end of the
runway.

Runway Lighting
• After crossing the threshold, pilots must complete a touchdown and
roll out on the runway. The runway visual aids for this phase of landing
are be designed to give pilots information on alignment, lateral
displacement, roll, and distance. The lights are arranged to form a
visual pattern that pilots can easily interpret.
• At first, night landings were made by floodlighting the general area.
Various types of lighting devices were used, including automobile
headlights, arc lights, and search lights. Boundary lights were added to
outline the field and to mark hazards such as ditches and fences.
Gradually, preferred landing directions were developed, and special
lights were used to indicate these directions. Floodlighting was then
restricted to the preferred landing directions, and runway edge lights
were added along the landing strips. As experience was developed,
the runway edge lights were adopted as visual aids on a runway. This
was followed by the use of runway center line and touchdown zone
lights for operations in very poor visibility.

Runway Edge Lights
• Runway edge lighting systems outline the edge of runways during night
time and reduced visibility conditions. Runway edge lights are classified by
intensity, high intensity (HIRL), medium intensity (MIRL), and low intensity
(LIRL). LIRLs are typically installed on visual runways and at rural airports.
MIRLs are typically installed on visual runways at larger airports and on
non-precision instrument runways, HIRLs are installed on precision-
instrument runways. Elevated runway lights are mounted on frangible
fittings and project no more than 30 in above the surface on which they
are installed. They are located along the edge of the runway not more
than 10 ft from the edge of the full-strength pavement surface. The
longitudinal spacing is not more than 200 ft. Runway edge lights are white,
except that the last 2000 ft of an instrument runway in the direction of
aircraft operations these lights are yellow to indicate a caution zone.

Runway Center line and Touchdown
Zone Lights
• As an aircraft traverses over the approach lights, pilots are
looking at relatively bright light sources on the extended
runway center line. Over the runway threshold, pilots continue
to look along the center line, but the principal source of
guidance, namely, the runway edge lights, has moved far to
each side in their peripheral vision. The result is that the central
area appears excessively black, and pilots are virtually flying
blind, except for the peripheral reference information, and any
reflection of the runway pavement from the aircraft‘s landing
lights. Attempts to eliminate this ―black hole‖ by increasing the
intensity of runway edge lights have proven ineffective. In order
to reduce the black hole effect and provide adequate guidance
during very poor visibility conditions, runway center line and
touchdown zone lights are typically installed in the pavement.

Runway End Identifier Lights
• Runway endidentifier lights (REIL) are installed
at airports where there are no approach lights
to provide pilots with positive visual
identification of the approach end of the
runway. The system consists of a pair of
synchronized white flashing lights located on
each side of the runway threshold and is
intended for use when there is adequate
visibility.

Taxiway Lighting
• Either after a landing or on the way to takeoff, pilots must maneuver the aircraft on the
ground on a system of taxiways to and from the terminal and hangar areas. Taxiway lighting
systems are provided for taxiing at night and also during the day when visibility is very poor,
particularly at commercial service airports.
• In order to avoid confusion with runways, taxiways must be clearly identified.
• Runway exits need to be readily identified. This is particularly true for high- speed runway
exits so that pilots can be able to locate these exits 1200 to 1500 ft before the turnoff
point.
• Adequate visual guidance along the taxiway must be provided.
• Specific taxiways must be readily identified.
• The intersections between taxiways, the intersections between runways and taxiways, and
runway-taxiway crossings need to be clearly marked.
• The complete taxiway route from the runway to the apron and from the apron to the
runway should be easily identified. There are two primary types of lights used for the
designation of taxiways. One type delineates the edges of taxiways and the other type
delineates the center line of the taxiway.

Taxiway Edge Lights
• Taxiway edge lights are elevated blue colored bidirectional lights usually
located at intervals of not more than 200 ft on either side of the taxiway.
The exact spacing is influenced by the physical layout of the taxiways.
Straight sections of taxiways generally require edge light spacing in 200-ft
intervals, or at least three lights equally spaced for taxiway straight line
sections less than 200 ft in length.
• Closer spacing is required on curves. Light fixtures are located not more
than 10 ft from the edge of full strength pavement surfaces. Taxiway
centerline lights are in-pavement bidirectional lights placed in equal
intervals over taxiway centerline markings.
• Taxiway centreline lights are green, except in areas where the taxiway
intersects with a runway, where the green and yellow lights are placed
alternatively.

Runway and Taxiway Marking
• In order to aid pilots in guiding the aircraft on
runways and taxiways, pavements are marked
with lines and numbers. These markings are of
benefit primarily during the day and dusk. At
night, lights are used to guide pilots in landing
and maneuvering at the airport.
• White is used for all markings on runways
and yellow is used on taxiways and aprons.

Runway Threshold Markings
• Runway threshold markings identify to the pilot the
beginning of the runway that is safe and available for
landing.
• Runway threshold markings begin 20 ft from the runway
threshold itself. Runway threshold markings consist of
two series of white stripes, each stripe 150 ft in length
and 5.75 ft in width, separated about the centerline of
the runway. On each side of the runway centerline, a
number of threshold marking stripes are placed.
• For example, for a 100-ft runway, eight stripes are
required, in two groups of four are placed about the
centerline. Stripes within each set are separated by 5.75
ft. Each set of stripes is separated by 11.5 ft about the
runway centerline.

Runway Centerline Markings
• Runway centerline markings are white, located on
the centerline of the runway, and consist of a line of
uniformly spaced stripes and gaps.
• The stripes are 120 ft long and the gaps are 80 ft
long. Adjustments to the lengths of stripes and gaps,
where necessary to accommodate runway length,
are made near the runway midpoint.
• The minimum width of stripes is 12 in for visual
runways, 18 in for non precision instrument runways,
and 36 in for precision instrument runways.
• The purpose of the runway centerline markings is to
indicate to the pilot the centre of the runway and to
provide alignment guidance on landing and takeoff.

Touchdown Zone Markings
• Runway touchdown zone markings are white and consist of groups of
one, two, and three rectangular bars symmetrically arranged in pairs
about the runway centerline.
• These markings begin 500 ft from the runway threshold. The bars are
75 ft long, 6 ft wide, with 5 ft spaces between the bars, and are
longitudinally spaced at distances of 500 ft along the runway.
• The inner stripes are placed 36 ft on either side of the runway
centerline. For runways less than 150 ft in width, the width and
spacing of stripes may be proportionally reduced.
• Where touchdown zone markings are installed on both runway ends
on shorter runways, those pairs of markings which would extend to
within 900 ft of the runway midpoint are eliminated.

Taxiway Centerline and Edge Markings
• The centerline of the taxiway is marked with a single
continuous 6-in yellow line.
• On taxiway curves, the taxiway centerline marking
continues from the straight portion of the taxiway at a
constant distance from the outside edge of the curve.
• At taxiway intersections which are designed for aircraft to
travel straight through the intersection, the centerline
markings continue straight through the intersection.
• At the intersection of a taxiway with a runway end, the
centerline stripe of the taxiway terminates at the edge of
the runway

GEOMETRIC DESIGN
79
Runway
1. Runway orientation
2. Basic Runway length
3. Runway configuration
4. Runway Geometrics
Taxiway
Exit taxiway
Terminal Design

RUNWAY
80
A runway is a rectangular area on the airport surfaceprepared
for the takeoff and landing of aircraft.
An airport may have one runway or several runways which are sited,
oriented, and configured in a manner to provide for the safe and efficient use
of the airport under a variety of conditions.
Several of the factors which affect the location, orientation, and number
of runways at an airport include local weather conditions, particularly
wind distribution and visibility, the topography of the airport and
surrounding area, the type and amount of air traffic to be serviced at the
airport, aircraft performance requirements, and aircraft noise.

RUNWAY ORIENTATION
81
Runway are always oriented in the direction of prevailing winds.
The reason behind this is to utilize the maximum force of the wind at
the time of take-off and landing of an aircraft.
Following points need to be considered while orienting the runways:
Avoiding delay in the landing, taxing and take-off operations.
Providing the shortest taxi distance possible from the terminal area to the
ends of runway.
Making provision for maximum taxiways so that the landing aircraft can
leave the runway as quickly as possible to the terminal area
Providing adequate separation in the air traffic pattern

Data required for runway orientation
82
wind
Map of area and contours
Wind data
Wind Direction: Tail Wind, Cross Wind & Head Wind
Fog characteristics
ICAO recommends maximum allowable cross components as
Field Length Maximum CW component
1500 or over 37 km/hr
1200 to 1499 m 24 km/hr
Less than 1200 m 19 km/hr

Wind Coverage
83
Wind coverage of airport is the percentage of time in a year during which
the cross wind component remains within the limit or runway system is
not restricted because of excessive cross wind. ICAO recommends
minimum wind coverage of 95%
Calm Period
This is the period for which the wind intensity remains below
6.4 km/hr
Wind Rose Diagram
Type 1: Duration and Direction of wind
Type 2: Duration, Direction and Intensity of wind

BASIC RUNWAY LENGTH
84
The FAA’sprocedure for estimating runway length is based on the
following data:
1. Designation of a critical aircraft.
2. The maximum takeoff weight of the critical aircraft at the airport.
3. The airport elevation.
4. The mean daily maximum temperature for the hottest month at
the airport.
5. The maximum difference in elevation along the runway centerline.

❖Correction for Elevation
❖As the elevation increases, the air density reduces. This in turn reduces
the lift on the wings of the aircraft and the aircraft requires greater
ground speed before it can rise into the air. To achieve greater speed,
longer length of runway is required.
❖ICAO recommends that the basic runway length should be increased
at the rate of 7% per 300m rise in elevation above MSL.
85

❖Correction for Temperature
❖The rise in airport reference temperature has the same effect as that of the
increase in elevation. Airport reference temperature is defined as the
monthly mean of average daily temperature (Ta) for the hottest month of the
year plus one third of the difference of this temperature and the monthly
mean of the maximum daily temperature (Tm)
❖Airport reference temperature = Ta + [(Tm –Ta)/3]
86

❖ ICAO recommends that the basic runway length after having been corrected for
elevation, should be further increased at the rate of 1% for every 10 C rise of airport
reference temperature above the standard atmospheric temperature at that elevation.
❖ The standard atmospheric temperature at the site can be determined by reducing the
standard sea level temperature of 150 C at the rate of
6.50 C per 1000 m rise inelevation.
87

❖ Check for Total Correction for Elevation and Temperature
❖ ICAO further recommends that, if the total correction for elevation plus
temperature exceeds 35% of the base runway length, these corrections
should then be further checked up by conducting specific studies at the site
by model tests.
❖Correction for Gradient
❖ Steeper gradient results in greater consumption of energy and as such longer
length of runway is required to attain the desired ground speed. FAA
recommends that the runway length after having being corrected for
elevation and temperature should be further increased at the rate of 20% for
every 1% of effective gradient.
88

Basic Runway Length
Normal Landing
The aircraft should come to a stop within 60% of landing distance
assuming that the pilot makes an approach at the proper speed and
crosses the threshold of the runway at a height of 15m.
The runway of full strength is to be provided for the entire landing
distance
90

Normal Take-off
The take-off distance must be 115% of the actual distance the aircraft
uses to reach a height of 10.5 m.
It requires a clearway at the end of the runway in the direction of take-off.
This should not be less than 15mwide. The upward slope of clearway
from the end of the runway shall not exceed 1.25%
91

Stopping in Emergency
Require either clearway or a stopway, or both.
(Stopway: Used for decelerating the aircraft and bringing it
to a stop during an aborted take-off.)
93

RUNWAY GEOMETRICS
95
Length of runway
Width of runway
Sight distance
Longitudinal and effective gradient
Rate of Change of longitudinal gradient
Transverse gradient
Safety area

Length and Width of Runway
Classifications of airports as per ICAO
Airport Type
Basic Runway Length (m) Width of
Runway
Pavement (m)
Maximum
Longitudinal
Gradient (%)
Maximum Minimum
A Over 2100 2100 45 1.5
B 2099 1500 45 1.5
C 1499 900 30 1.5
D 899 750 22.5 2.0
E 749 600 18 2.0
19

Sight Distance
97
No sight distance restrictions, as the longitudinal gradients for the
runway are less.
Adherence to runway longitudinal gradient standards provides
adequate line of sight.
Airport Category Y (m) X
ICAO code letterA 1.5
Half runway length
ICAO code letter B 2.1
Half runway length
ICAO code letter C,D and E
3.0
Half runway length

Longitudinal Gradient
The longitudinal gradient increases in required runway length.
It also affects the aircraft performance.
These should be as flat as possible to avoid excessive engine thrust
98

Change of Longitudinal Gradient
The abrupt grade change may cause premature lift-off of aircraft during take
off.
The change in gradient should be smooth through the provision of
vertical curves.
No vertical curve is required if the grade change is less than 0.4 %.
99

Transverse Gradient
100
Provided for quick disposal of surface water.
Ponding of water is hazardous for aircraft operation.
Minimum recommended transverse slope is 1%.
For rigid pavement it may be kept as low as 0.5.
Slope up to 2% are permitted for runways that serve smaller classes of aircraft.
For other runways maximum transverse slope is 1.5%.
For shoulders slope of 3-5% is recommended.

Safety Area
The safety area is an area which is cleared, drained and graded. It
includes the structural pavement, shoulders on either side of runway
and the additional width.
101

TAXIWAY
102
Taxiway are defined as paths on the airfield surface for the taxing of
aircraft and are intended to provide linkage between one part of the
airfield.
Aircraft movement on taxiways are essentially ground movements
and are relatively slow.

Types of taxiway
Apron taxiway: Located on the periphery of an apron to
provide uninterrupted taxing of aircraft across the apron.
Dual parallel taxiway: Two parallel taxiways on which
aircraft can taxi in opposite directions.
Terminal taxiway: It is a portion of an apron intended to
provide access to only aircraft stands or gate positions.
103

Taxiway Geometrics
Length
As short as possible
It will increase as number of taxiways have to be provided along the runway.
Longitudinal Gradient
Level taxiways are operationally more desirable
If gradient is steep it affects fuel consumption
As per ICAO gradient of 3% for A and B types of airport and 1.5%
for C, D and E types of airport. 27

Width of taxiway
Width of taxiway is lesser than runway, as aircraft is not
airborne and speeds are small.
There is not much variability in the maneuverability of
aircraft and nose of aircraft follows the taxiway centerline.
Width varies between 22.5 and 7.5

Sight distance
As speed of aircraft on taxiway is lower than the speed on
runway, the smaller value of sight distance will be sufficient
on the taxiway.
Airport Type Y(m) X (m)
A 1.5 150
B 2.0 200
C, D and E 3.0 300

Turning Radius
Change in aircraft path is done by providing a horizontal
curve.
The design should be such that the aircraft can negotiate the curve without
significantly reducing the speed.
Relationship between exit speed and radius of curve
Radius = V2/125f;
V is in Kmph and f is coefficient of friction =0.13

• ICAO has indicated the relationship between aircraft speed and the radius of
curvature of taxiway curves as illustrated inTable.
TAXIING SPEED(kmph) RADIUS OF EXITCURVE
(m)
16 15
32 60
48 135
64 240
80 375
96 540
Source: International Civil Aviation Organization

Radii of curvature and entrance
curves for Taxiways

EXIT TAXIWAY
The function of exit taxiways, or runway turnoffs as they are
sometimes called, is to minimize runway occupancy by landing
aircraft.
Exit taxiways can be placed at right angles to the runway or some
other angle to the runway.
When the angle is on the order of 30°, the term high-speed exit is
often used to denote that it is designed for higher speeds than other
exit taxiway configurations.

COMMON EXIT TAXIWAY
CONFIGURATION

FAA Taxiway Curvature Dimensional
Standards (ft)

TERMINAL AREA
It is portion of an airport other than landing area.
It serves as a focal point for the activities on the airport.
Terminal area includes
Terminal and operational buildings
Vehicle parking area
Aircraft service hangars
Facilities for cargo handling and storage
Facilities for passengers

Terminal building usually refers to a building mainly, used for passengers,
airline and administration facilities.
Its layout is such as to offer the enplaning passengers, the convenient and direct
access from the vehicle platform or street side of the building, through booking
and waiting rooms, to the aircraft loading positions on the apron.
Deplaning passengers are also provided with a direct route from the aircraft to
the baggage claim counter and then to the vehicle platform.

GENERAL AIRPORTTERMINAL LAYOUT

 Linear
Terminal Types
Curvilinear →

Finger
Piers
Transporter
Satellite
4
6

VERTICAL DISTRIBUTION CONCEPT
120
The basis for distributing the primary processing activities
in a passenger terminal among several levels is mainly to
separate the flow of arriving and departing passengers.
The decision concerning the number of levels a terminal
facility should have depends primarily on the volume of
passengers and the availability of land for expansion in the
immediate vicinity.

VERTICALDISTRIBUTION CONCEPT: (a)single level (b)second level loading (c)two
level system. (FAA)
121

TERMINAL BUILDING SPACE
REQIREMENT
Component
Space Required in meter square Typical Peak
Hour per Passenger
Ticket lobby 1.0
Baggage claim 1.0
Departure lounge 2.0
Waiting rooms 1.5
Immigration 1.0
Customs 3.0
Amenities 2.0
Airline operations 5.0
Total gross area
Domestic 25.0
International 30.0

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