AIRPORT ENGINEERING

Prepared By:

Mrs. Taheseen Sultana Assistant Professor

CED ,DCET,

Introduction

• Airport Engineering encompasses the planning, design, and construction of terminals, runways, and navigation aids to provide for passenger and freight service.
• An airport is a facility where passengers connect from ground transportation to air transportation
• AIRFIELD is an area where an aircraft can land and take off, which may or may not be equipped with any navigational aids or markings

Air transportation

• One system of transportation which tries to improve the accessibility to inaccessible areas
• Provides continuous connectivity over water and land
• Provide relief during emergencies and better compared to others some times
• Saves productive time, spent in journey
• Increases the demand of specialized skill work force

Air transportation

• Helps tourism, generates foreign reserves
• Requires heavy funds during provision and maintenance
• Highly dependent on weather conditions compared to other modes
• Requires highly sophisticated machinery
• Adds to outward flow of foreign exchange

▫ Purchase of equipment, airbuses etc.

• Safety provisions are not adequate.

▫ Providing a support system during the flight is complicate

• Specific demarcation of flight paths and territories is essential

Development of Air Transport

• 1903 – first successful flight by Wilbur and Orville Wright at

Kitty Hawk, North Carolina

• 1909 – Louis Bleriot crossed English channel to England
• 1911 – Post was carried by air in India from Allahabad to Naini (pilot: Henri Piquet) crossing Ganga
• 1912 – Flight between Delhi and Karachi
• 1914 – Air passenger transport began in Germany

Development of Air Transport

• 1918 – first international service between France and Spain

​

• 1919 – London – Paris flight
• 1919 – International Commission on Air Navigation (ICAN) was established
• 1919 – 6 European airlines formed in Hague the International Air Traffic Association (IATA) to control the movement of air traffic and have a coordinated approach

• 1928 – Havana Convention on civil aviation

​

• 1929 – Warsaw convention on civil aviation

• 1944 – International civil aviation convention
• 1944 – Chicago convention, establishing (international civil aviation organization)

provisional

ICAO

• 1945 – International Air Transport Association (IATA)

established in meeting at Havana, Cuba

​

• 1947 – ICAO was established as a body of United Nations

• 27, July 1949 – worlds first jet airliner made its

journey from Hatfield airport

• 1954 – Boeing Dash 80 type prototype, B707 first flight
• 1969 – Concorde first flight
• 2006 – Airbus A328 made first flight (one of the biggest passenger air craft i.e., 800 persons)

Air Transport in India

• 1911 – post was carried by air in India from Allahabad to Naini
• 1912 – flight between Delhi and Karachi
• 1927 – Civil Aviation Department was established
• 1929 – Regular air service between Delhi and Karachi
• 1932 – Tata airways ltd was setup
• 1933 – Indian trans-continental airways ltd was formed

• 1938 – 153 aircrafts were registered
• 1946 – Air transport licensing board was established
• 1947 – Tata changed its name to Air India Ltd
• 1948 – Air India International ltd was established by government
• 1953 – Air Transport Corporation bill was made, provision for establishing two corporations, one for the domestic services and other for the international services.

• 1972 - The International Airport Authority of India (IAAI) was setup

▫ to coordinate the international aviation from different locations of the

country

• 1981 - Vayudoot service was started. It merged into Indian Airlines in 1993
• 1985 - Air taxi policy
• 1994 -Airport Authority of India (AAI) was formed by merging International Airport Authority of India (IAAI) and National Airports Authority (NAA).

Airport Authority of India

• Controls overall air navigation in India
• Constituted by an act of parliament and it came into being on 1st

April, 1995

• Formed by merging NAA (National Airport Authority) and IAAI (International Airport Authority of India)
• Functions of AAI

▫ Control and management of the Indian airspace extending beyond

the territory limits

▫ Design, development and operation of domestic and international airports

▫ Construction and management of facilities

Functions of AAI

▫ Development of cargo ports and facilities

▫ Provision of passenger facilities and information systems

▫ Expansion and strengthening of operating area

▫ Provision of visual aids

▫ Provision of communication and navigational aids (ex: Radar systems)

Airport Layout

Airport

An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport. An airport consists of at least one surface such as runway for a plane to take off and land, a helipad, or water for takeoffs and landings, and often includes buildings such as control towers, hangars and terminal buildings.

SCHEMATIC ARRANGEMENT AT AIRPORT

Components of An Airport Layout

• 1. Runway
• 2. Terminal Building
• 3. Apron
• 4. Taxiway
• 5. Aircraft Stand
• 6. Hanger
• 7. Control Tower
• 8. Parking

Runways

A runway is the area where an aircraft lands or takes off. It can be grass, or packed dirt, or a hard surface such as asphalt or concrete. Runways have special markings on them to help a pilot in the air to tell that it is a runway (and not a road) and to help them when they are landing or taking off. Runway markings are white.

.

RUNWAY

Terminal Buildings

• Also known as airport terminal, these buildings are the spaces where passengers board or alight from flights.
• These buildings house all the necessary facilities for passengers to check-in their luggage, clear the customs and have lounges to wait before disembarking.
• The terminals can house cafes, lounges and bars to serve as waiting areas for passengers.
• Ticket counters, luggage check-in or transfer, security checks and customs are the basics of all airport terminals.
• Large airports can have more than one terminal that are connected to one another through link ways such as walkways, sky-bridges or trams.
• Smaller airports usually have only one terminal that houses all the required facilities.

TYPICAL LAYOUT OF TERMINAL BUILDING

Aprons

• Aircraft aprons are the areas where the aircraft park.
• Aprons are also sometimes called ramps.
• They vary in size, from areas that may hold five or ten small planes, to the very large areas that the major airports have.
• Unlike the runways or taxiways, vehicles can use aprons.

Taxiway

A taxiway is a path on an airport connecting runways with ramps, hangar s, terminals and other facilities. They mostly have hard surface such as asphalt or concrete, although smaller airports sometimes use gravel or grass.

Control Tower

A tower at an airfield from which air traffic is controlled by radio and observed physically and by radar.

Parking

Parking is a specific area of airport at which vehicles park

Aircraft Stand

A portion of an apron designated as a taxiway and intended to provide access to aircraft stands only.

What is AIRCRAFT?

• Any machine which finds support in atmosphere due to reactions of

the air is defined as an aircraft.

• It can be heavier or lighter than the air and may be power or non- power driven.
• For example airships are lighter than air and are power driven whereas balloons are lighter than air and non-power driven.

❖

Aeroplanes and Helicopters are heavier than air and also power

driven.

What is AIRCRAFT?

Airship

Balloons

Components of Aircraft

TYPES OF AIRCRAFT

AIRBUS

BOEING

Component parts of an Aeroplane

Its essential parts are as given below:

• 1 Engine
• 2 Propeller
• 3 Fuselage
• 4 Wings
• 5 Three controls
• 6 Flaps
• 7 Tricycle under-carriage

Engine

• The main purpose of an aircraft engine is to provide a force for propelling the aircraft through the air.
• Aircraft can be classified according to their propulsion as follows
• (I) Piston engine
• (ii) Jet engine
• (iii) Rocket engine

(I) Piston engine : It is powered by gasoline fed reciprocating engine

and is driven by propeller or airscrew.

https://www.youtube.com/watch?v

=U5SAttn-e4E

WORKING OF PISTON ENGINE

https://www.youtube.com/watch?v=KjiUUJdPG X0

Working of Turbo-Jet Engine

https://www.youtube.com/watch?v=1DG4f2um clk

Working of Ram Jet Engine

PROPULSION LIMITS

Propeller

• This is provided in the conventional piston engine aircrafts as well as in turbo prop engines.
• It has usually 2 or more blades driven round in circular path.
• Blades deflect air backwards with an acceleration and thus

forward thrust is imparted to the Aeroplane.

• When propeller are in front it is described as tractor type.
• When the engine and propeller are kept behind it is called as pusher installation

Fuselage

• It forms the main body of the aircraft.
• The fuselage includes the cabin and/or cockpit, which contains seats for the occupants and the controls for the airplane. In addition, the fuselage may also provide room for cargo and attachment points for the other major airplane components.
• Some aircraft utilize an open truss structure. The truss-type

fuselage is constructed of steel or aluminium tubing.

• Strength and rigidity is achieved by welding the tubing together into a series of triangular shapes, called trusses.

WARREN TRUSS

• Longerons + only Diagonal Members
• Force transfer to every others structure
• Capable to carry tension + compression
• Reduce amount of webs work
• More space , strength , rigidity
• Better streamline

MONOCOQUE

In this method, the exterior surface of the fuselage is also the primary structure. A typical early form of this was built using molded plywood.

A later form of this structure uses fiberglass cloth impregnated with polyester or epoxy resin, instead of plywood, as the skin.

SEMI-MONOCOQUE

This is the preferred method of constructing an all- aluminum fuselage. First, a series of frames in the shape of the fuselage cross sections are held in position on a rigid fixture, or jig. These frames are then joined with lightweight longitudinal elements called stringers. These are in turn covered with a skin of sheet aluminum, attached by riveting or by bonding with special adhesives. Most modern large aircraft are built using this technique, but use several large sections constructed in this fashion which are then joined with fasteners to form the complete fuselage.

Semi-monocoque Structure of an airplane

Three Controls

• There are three axes about

which an aircraft in space may

move. These axes

and the

possible aircraft movements

are shown in the Figure.

• The movement of aircraft about the X axis is called lateral or rolling movement.
• The movements about Y and Z axes are called pitching and yawing movements respectively.
• To control these movements, the airplane is provided with three principal controls, viz., (i) elevator (ii) rudder and (iii) aileron.

Three Axes of Movements

1. Elevator
• It consists of two flaps capable of moving up and down through an angle of 50° to 60°. They are hinged to a fixed horizontal surface (called a tail plane or stabilizer) placed at the extreme rear of the fuselage. It controls the pitching or up and down movements of the aircraft.
2. Rudder
• It Consists of a streamlined flap hinged to a vertical fin provided at the tail end of the fuselage. It can be moved right or left of the vertical axis through an angle of about 30°. It is utilized for the turning or yawing movement of the aircraft.
3. Aileron
• It is a hinged flap which is fixed in the trailing edge of the wing near the wing tip. It is so rigged that when aileron in one wing is pulled up that in other is pulled down. The net effect gives a very powerful rolling control to the aircraft. It is to balance the plane when tilted by a gust of wind. It also permits to tilt the machine purposely like while describing a circle.

Flaps

• These are somewhat similar to ailerons and are used in landing and take off. When they are projected into the air, they produce immediate reduction in the speed of the aircrafts and thus serve as air brakes

Tricycle Under-Carriage

• The landing gear system to support the aircraft while it is in contact with the ground, It has two principal functions to perform as listed below
• The suitable assembly of wheels allow aircraft to move on the runway carrying its entire weight.
• The aircraft during landing touches the ground with certain velocity. The undercarriage system permits to occur it smoothly.

AIRCRAFT CHARACTERISTICS

Aircraft characteristics are of prime importance to the airport planner and

designer. The following characteristics need to be studied

• 1 Type of propulsion
• 2 Size of aircraft
• 3 Minimum turning radius
• 4 Minimum circling radius
• 5 Speed of aircraft
• 6 Capacity of aircraft

• 7 Aircraft weight and wheel configuration _•

• 8 Jet blast
• 9 Fuel spillage
• 10 Noise
• 11 Range

• 12 Take off and landing

pressure and

distance.

13 Tire contact area

Types of Propulsion

• The size of aircraft, its circling radius, speed characteristic, weight

carrying capacity, noise nuisance etc. depend upon the type of propulsion of the aircraft.

• The performance characteristics of aircrafts, which determine the basic runway length, also depend upon the type of propulsion. That heat nuisance due to exhaust gases is a characteristic of turbo jet and turbo prop engines.

Size of Aircraft

The sizes of aircraft involves following important dimensions:

(i) Wing span (ii) Fuselage length (iii) Height (iv) Distance between main gears, i.e. gear tread (v) Wheel base and (vi) Tail width.

The wing span decides the width of taxiway, separation clearance between two parallel traffic ways, size of aprons and hangars, width of hangar gate etc. The length of aircraft decides the widening of taxiways on curves width of exit taxiway, sizes of aprons and hangars etc. The height of aircraft, also called as empennage height, decides the height of hangar gate and miscellaneous installations inside the hangar.

The gear tread and the wheel base affect the minimum turning radius of the

aircraft.

Minimum Turning Radius

• In order to decide the radius of taxiways, the

position

hangars

of aircrafts in loading aprons and

and to establish the path of the

movement of aircraft, it is very essential to study the geometry of the turning movement of aircrafts. The turning radius of an aircraft is illustrated in the Figure.

To determine the minimum tuning radius, a line is drawn through the axis of the nose gear when it is at its maximum angle of rotation The point, where this line intersects another line drawn through the axis of the two main, gears, is called the center of rotation.

•

Turning Radius of Aircraft

Minimum Circling Radius

There is certain minimum radius with which the aircraft can take turn in space. This radius depends upon the type of aircraft air traffic volume and weather conditions. The radii recommended for different types of aircrafts are as follows

1. Small general aviation aircrafts under UFR conditions, 1.6 km (1 mile)
2. Bigger aircrafts, say two piston engine under VFR conditions = 3.2 km (2

mile)

3. Piston engine aircrafts under IFR conditions. = 13 km (8 miles)
4. Jet engine aircrafts under IFR conditions= 80 km (50 miles)

The two nearby airports should be separated from each other by an adequate distance so that the aircrafts simultaneously landing on them do not interfere with each other. If the desirable spacing between the airports cannot he provided, the

landing and takeoff aircrafts in each airport will have to be timed so as to avoid

collision.

Speed of Aircrafts

The speed of aircraft can be defined in two ways viz. ground speed and air speed Air speed is the speed of aircraft relative to the wind. Thus, if the aircraft is at a speed of 500 kmph and there is a head wind of 50 kmph air speed will be 450 kmph.

Aircraft Capacity

The number of passengers, baggage, cargo and fuel that can be accommodated in the aircrafts depends upon the capacity of aircraft. The capacity of aircraft using an airport have an important effect on the capacity of runway systems as well as that of the passenger processing terminal facilities.

Weight of Aircraft & Wheel Configuration

Weight of the aircraft directly influence the length of the runway as well as the structural requirements i.e. the thickness of the runway, taxiway, apron & hangars. It depends not only on the weight of the passenger baggage, cargo and fuel it is carrying and its structural weight, but also on the fuel which is continuously decreasing during the course of the flight.

Maximum gross take off weight : max. load which the aircraft is certified to carry during

take off.

Maximum structural landing weight : difference between the gross take off weight and

weight of fuel consumed during the trip.

Operating empty weight : weight of aircraft including crew and all the necessary gear required for flight.

Pay load : total revenue producing load and it includes weight of passengers and their baggage, cargo etc.

Zero fuel weight : it is the weight above which all additional weight must be fuel

Jet Blast

At relatively high velocities, the aircrafts eject hot exhaust gases, The velocity of jet blast may be as high as 300 kmph. This high velocity cause inconvenience to the passengers traveling in the aircraft. Several types of blast fences or jet blast deflector are available to serve as an effective measure for diverting the smoke ejected by the engine to avoid the inconvenience to the passengers. Since, the bituminous (flexible) pavements are affected by the jet bust, therefore, it s desirable to provide cement concrete pavement at least at the touch down portion to resist the effect of the blast in preference to the bituminous pavements. The effect of the jet blast should also be considered for determining the position, size and location of gates.

Noise

• The most serious problem facing aviation is the noise.
• The major sources are the machinery noise during landing and the primary jet during the take off.
• The disturbance caused during the take off is more severe.

Take off and landing distance

It helps in determining the minimum runway length required for a particular type of aircraft. It depends upon various factors such as altitude of the airport, gradient of the runway, intensity and direction of the wind, weight of the aircraft at the time of landing and take off, etc.

Selection of site for airport

▫ Air traffic potential

🞄 Magnitude of passenger and freight traffic expected

▫ Adequate access

▫ Sufficient airspace

🞄 Circling radius should be taken care

▫ Sufficient land

🞄 Various facilities, terminal buildings, security systems

▫ Atmospheric and meteorological conditions

▫ Availability of land for expansion

▫ Availability of utilities

AIRPORT SITE SELECTION

Following factors influence the site selection of an airport

• Atmospheric and meteorological conditions
• Availability of land for expansion.
• Availability of utilities
• Development of the surrounding areas
• Economy of construction
• Ground accessibility
• Presence of other airports.
• Regional plan
• Soil characteristics
• Surrounding obstructions
• Topography
• Use of airport

• Atmospheric and meteorological conditions

▫ Visibility

🞄 Fog, smoke, haze

🞄 Affected by wind

🞄 Development of area (industrial)

🞄 Causes reduction in frequency and hence in capacity handling

▫ Wind

🞄 Direction and intensity

🞄 Associated topographical features (hills, valley)

🞄 Windward/leeward side

🞄 Locating development w.r.t site of airport

• Availability of land for expansion

▫ Future prediction of air traffic

🞄Land for parking vehicles, providing facilities

▫ Land cost at later stage

▫ Availability of land at later stage

• Availability of utilities

▫ Water, power etc.,

▫ Sewerage, communication etc.

• Development of surrounding area

▫ Residential or sensitive area

▫ Industrial development

🞄Height of development

🞄Zoning laws

▫ Noise pollution

▫ Movement of air pollution

▫ Birds and hits at engines

• Economy of construction

▫ Alternate sites to be examined

▫ Availability of local construction material

▫ Terrain even or not

▫ Problematic areas

🞄 Water logging areas

🞄Reclaimed areas

• Ground accessibility

▫ Travel time in air vs on ground

▫ Easily approachable using all modes

▫ Proximity to areas of trip generation

▫ Facilities for private vehicle users

▫ Efficient transport system

• Presence of other airport

▫ Traffic volume

▫ circling radius

▫ Types of air crafts in different airports

▫ Type of operating facility

🞄 Instrumental flight rules, design flight rules

▫ Separation distance between radii

▫ May cause

🞄 Accidents, reduction in capacity

• Characteristics of soil

▫ Strength of soil sub grade

▫ Drainage of soil

▫ Level of water table and its impact

🞄 Sub-soil drainage effects

▫ Valley side may have flooding

▫ Soil with good amount of pervious material like sand or gravel is considered good

• Use of airport

▫ Civil or for military

▫ Adaptability for other usage during emergencies

• Surrounding area obstructions

▫ Clear air space for take off and landing

▫ High rise buildings not allowed

▫ High trees are cleared off

▫ Zoning laws are made to take care

RUNWAY

• “Rectangular area on an airport which is used for landing and take-off operations“
• Important questions before deciding runway orientation.
• Why Runway orientation is so important in airport planning?
• What is Current practice to layout a runway?
• What number of runways must be provided in airports?

Why Runway orientation is so important in airport planning?

• The direction of the runway controls the layout of the other

airport facilities such as passenger terminals, taxiways, apron configurations, circulation roads and parking facilities

- means the rest of the facilities which needs to be provided on any of the airport are governed by the orientation of the runway.

What is Current practice to layout a runway?

• Runways are always orientated in the direction of the prevailing winds, so that we can utilize the force of the wind during take - off and landing operations
• In the case of take-off operations, this wind will help us in generating the lift, whereas during the landing operations the same wind will help in generating the drag, so as to stop the landing aircraft

What number of runways must be provided in airports?

• It depends upon the volume of traffic

Information required for Wind Orientation:

​

• Preliminary Information

​

• Head Wind

​

• Cross Wind Component

​

• Wind Coverage

​

• Wind Rose

What is Head wind?

• It indicates the wind from the opposite direction of the head or

nose of the aircraft while it is landing or taking off.

​

What is Cross wind component

• It is not possible to get the direction of opposite wind in direction parallel to the centreline of the runway length everyday or throughout the year.

Nose of Plane

• The wind may blow making some angle with the centre line of the runway.
• The cross wind component depends upon size of aircraft and the wing configuration.

Recommendations for cross wind component by FAA:

• For small aircraft – (CWC > 15 kmph)

​

• For mixed traffic – (CWC > 25 kmph)

​

• For airports serving big aircrafts – (CWC > 35 kmph)

•

Note for airport serving bigger aircrafts recommendation

is given by ICAO

What is Wind coverage

• The percentage of time in a year during which the crosswind

​

component remains within limit of 25kmph, is called the wind

coverage of the runway.

• The orientation of the runway should be such minimum wind coverage of about 95% is obtained.

that the

• For busy airports, the wind coverage may be increased to as

​

much as 98% to 100%

What is Calm Period?

• The percentage of time during which the intensity of wind is < 6.4kmph or (6)kmph is called calm period.
• For the table given, Calm period = 100 – 88

= 12%

• Calm period does not have any influence on landing and take-off operations of an aircraft

Wind Rose

• The graphical representation of direction, duration and intensity of wind obtained from wind data is called wind rose.
• Wind data – at least 5yrs, preferably 10yrs.
• Wind rose diagram helps in analyzing the wind data and obtaining the most suitable direction of the runway.

Wind Rose - I

Wind Rose - I

• Wind Rose diagram is a 360° circular curve
• It is divided into 16 parts of 22.5° each.
• The directions are :

N,S,E,W,NW,NE,SW,SE,NNE,NNW,SSE,SSW,ENE,ESE,WNW,WSW

• Each circle represents duration of wind to a certain scale.
• The deviation can be sometimes taken as 33°

Wind Rose - I

• The radial line indicate the wind direction and each circle represents the duration of wind.
• The values of percentage of time in a year during

plotted along the corresponding directions.

which wind blows from different direction are

All

plotted points are then joined by straight line.

• The best direction of runway is usually along the direction of longest line on wind rose diagram.
• Does not account the effect of cross wind component.

Wind rose diagram – Type II

• Circle represents the wind intensity to some scale. The values in each segments represents the percentage of time in a year during the wind blows with particular intensity form the respective direction.
• The procedure for determining the orientation of runway is as follows:
• Step1 : draw three equally 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 same scale with which wind rose diagram is drawn.
• Step2 : 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.

• Step3 : with the centre of the wind rose, rotate the tracing paper and place it in such a position that the sum of all values indicating the duration of wind, with in two outer parallel lines, is the maximum. The runway should thus oriented along the direction indicated by central line. The wind coverage can be calculated by summing up all the percentages shown in segment. The percentage value is assumed to be equally distributed over the entire area of the segment.

104

Change in the direction of the runway

• The ideal orientation decided from the study of the wind rose diagram may have to be slightly altered or changed because of the following factors.
• Excessive grading: The runway orientation may need alteration due to excessive grading and earthwork, even if orientation is satisfactory
• Noise nuisance: If the runway orientation, is along the direction where places of developed residential areas and places of public assembly etc. falls within take-off path, it is desirable to alter the orientation.
• Obstructions: For layout of runway, obstruction free approaches are much more essential than cross wind component. Hence if orientation is such that provides more obstructions although it has greater wind coverage, it is desirable to such the orientation

Basic runway length

• It is the length of runway under the following assumed condition at the airport:
• Airport elevation is at sea level,
• Temperature at airport is standard (15⁰ c),
• Runway is leveled in the longitudinal direction,
• No wind is blowing on runway,
• Aircraft is loaded at its full loading capacity,
• There is no wind blowing on the way to the destination,
• En route temperature is standard.

• The following case are considered for determining the basic runway length
• Normal landing case
• Normal take-off case
• Engine failure case
• Note for Jet Engine all three cases are considered while for Piston Engine only 1^st and 3^rd cases are considered.
• The cases which works out the longest runway length is finally adopted

1. Normal landing case

• The normal landing case requires that an air craft should come to a stop within 60% of the landing distance. The runway of full strength pavement is provided for the entire landing distance.

15 m

stop

60% of landing distance

landing distance

Runway

2. Normal take-off case

• The normal take-off case requires a clearway which is an area beyond the runway and is in alignment with the centre line of runway. The width of clearway is not less than 150m and is kept free from obstruction. The clearway ground area or any object on it should not project a plane inclined upward at a slope of 1.25 percent from runway end

Clearway ≤ ½ of this distance

10.5m height

Lift-off distance

115% of Lift-off distance

Distance to 10.5m height

115% of distance to 10.5m height ( take-off distance) Longitudinal section

Runway

​

​

Clearway

Min 150m

Plan

Normal Take-off Case

3.Engine Failure Case

• The engine failure case may require either a clearway, or a stop way, or both.
• Stop way is an area beyond the runway and centrally located in alignment with the centre line of runway.
• Stop way is used for decelerating the aircraft and bringing it to stop during aborted take-off.
• If the engine has failed at a speed, less than the designated engine failure speed, the pilot decelerate the aircraft and make use of stop way.
• If however, the engine fails at a speed higher than the designated speed, there is no other option to the pilot except to continue take-off. The pilot may later take a turn in the turning zone and land again for a normal take-off.

Lift-off distance

Accelerated stop distance

Distance to 10.5m height ( take-of distance )

​

​

Longitudinal section

Runway

Clearway

Min 150m

Plan Engine Failure Case

Engine

Failure

Clearway ≤ ½ of this distance

Decelerated – stop distance ^{10.5m height}

Stop way

Clear way

Stop way

Correction for Elevation, Temperature and

Gradient

• The basic runway length is for mean sea level elevation having standard atmospheric conditions.
• For any change in elevation, temperature and gradient for actual site of construction, necessary corrections are to be applied to obtain the length of runway.

Correction for Elevation

• The air density reduces as the elevation increases, this in turn reduces the lift on the wings of the aircraft and the aircraft requires greater ground speed before aircraft becomes airborne. To achieve greater speed, longer length of runway is required.
• ICAO recommends that basic runway length should be increased at the rate of 7% per 300m rise in elevation above MSL.

Correction for Temperature

• The rise in airport reference temperature has the same effect as that of the increase in elevation.
• Airport reference temperature

= T_a + (T_m – T_a )/3

• T_a = monthly mean of avg. daily temp. for the hottest month of the year.
• T_m = monthly mean of the maximum daily temp for the same month
• ICAO – 1% for every 1⁰c rise in airport reference temp.
• The standard temperature at the airport site can be determined by reducing the standard mean sea level temperature of 15 degree Celsius at the rate of 6.5 degree Celsius per thousand metre rise in elevation.

Check for total correction for elevation plus temperature

• ICAO further recommends if the total correction for elevation plus temp. exceeds 35% of the basic length, these correction should be further checked up by conducting specific studies at the site by model test.

Correction for gradient

• Steeper gradient results in greater consumption of energy.
• ICAO does not recommends any specific correction for the gradient.
• According to FAA, Runway length after being corrected for elevation and temp. should be further increased at the rate of 20% for every 1% of specific gradient.
• Specific gradient – is the max. difference in elevation between the highest and lowest point of runway divided by the total length of runway.

Runway Length and Width

The basic length of runway recommended by ICAO for different types of airport are given below:

Width and length of safety area

• Safety area consists of the runway plus the shoulder on either side of runway plus the area that is cleared, graded and drained.
• The shoulder are usually unpaved as they are used during emergency. The shoulders on the

either side of runway

openness to the pilot

impart a sense of and improve his

psychology during landing and take off.

• The length of the safety area is equal to the length of runway plus 120m.

Taxiway:

It is a path for an aircraft at airport connecting runways with aprons, hangars etc.

Layout of taxiway

1. Arrangement

: Aircraft which has just landed does not

interfere with the aircraft taxiing to take off

2. Busy airports: Taxiways should be located at various points along the runway , it will be then be possible for the landing aircraft to leave the runway as early as possible for making it clear for use by other aircraft. Such taxiway is known as exit taxiway.
3. Crossing : Crossing or intersection of taxiway and active

runway should be avoided.

4. Route: the route of taxiway should be made in such a way that it results in the shortest practicable distance from the terminal area to the end of the runway used for the take off
5. High turn off speed : if exit taxiways are designed for high turn off speeds, the runway occupancy of the landing aircraft is reduced and it will thus increase the airport capacity

Geometric Design Standards

• Length of taxiway
• Width of taxiway
• Width of safety area
• Longitudinal gradient
• Transverse gradient
• Rate of change of longitudinal gradient
• Sight distance
• Turning radius

Length of Taxiway

• It should be as short as practicable.
• No specifications are recommended by any organization.

Width of taxiway

• Width of taxiway is lower than the runway width (because when aircrafts run on taxiway they are not airborne)
• The speed of an aircraft on a taxiway is also less than the runway (the advantage of this is that pilot can manoeuvre the aircraft over a smaller width of taxiway)

Width of safety area

• This area includes taxiway pavement on either side that may be partially paved plus the area that is graded and drained.
• A width of 7.5m of shoulders adjacent to the pavement edges should be paved with light strength material.

.

Why shoulders are paved?

• Because after the arrival of jet blast, the amount of jet exhaust emitted from the engine especially during take-off operation is quite high which causes soil erosion of material used in shoulders, hence the shoulder materials is needed to be paved
• Shoulders are paved with following particulars:
• The shoulder must be thick enough to support the airport petrol vehicles and the sweeping equipment’s.
• The shoulders should normally be treated with bitumen.
• The surface should be made of such materials that disintegration due to hot blast of jet engine does not occur
• The surface should be smooth and impervious.

Longitudinal Gradient

ICAO recommends that the longitudinal gradient should not exceed 1.5% for A and B types and 3% for C,D and E types

Transverse Gradient

• This is essential for quick drainage of water.
• ICAO has recommended that the transverse gradient should not exceed 1.5% for A,B and C and C types and 2% for D and E types of airports.

Rate of change of longitudinal gradient

ICAO recommends that the rate of change of slope in longitudinal direction should not exceed 1% per 30 m length of vertical curve for A,B and C types and 1.2% for D and E types of airports.

Sight Distance

• ICAO has recommended that the surface of taxiway must be visible from 3m height for a distance of 300m for A,B and C types and distance of 250 m be visible for 2.1m height for D and E types of airports.

Turning radius

• Whenever there is a change in the direction of taxiway a horizontal curve is

provided.

• It is necessary to design the curve in such a way that aircraft can negotiate it without reducing the speed’
• Circular curve is most suitable for such cases and the radius of horizontal

curve is obtained by :

_V2

^R= 125f

V = speed in kmph,

coefficient of friction f = 0.13

• For airport serving large subsonic planes, the minimum value of radius of curvature is taken as 120m, irrespective of the speed.
• For supersonic planes, the minimum value of radius of curvature is taken as 180m.
• A supersonic aircraft is an aircraft able to fly faster than the speed of sound (Mach number 1).
• A subsonic aircraft is an aircraft with a maximum speed less than the speed of sound (Mach number 1).

According to Horonjeff’s equation, the radius of curve is given by,

​

0.388 W²

^R= 0.5 T − S

Where, R = radius of centre line of taxiway in ‘m’ W = Wheel base of aircraft in ‘m’

T = width of taxiway pavement in ‘m’ (assume 22.5m)

S = distance between point of midway of main gears and the

edge of taxiway pavement.

Exit Taxiway

Function is to minimize the runway occupancy by the landing aircraft . Its location depends upon the following factors:

• Air traffic control : rapidity and manner in which air traffic control can process arrivals.
• Exit speed : the maximum speed with which the aircraft can turn and enter the exit way is governed by the type of aircraft . The value of exit speed will decide the location of exit taxiway.

• Location of runways : location of runways relative to the terminal area.
• Number of exits: the number of exit taxiway to be provided will decide their location. If only 2 exit taxiways are to be provided , they will be naturally provided at the ends of runway. If more than 2, then they will be provided along the length of runway.
• Pilot variability : a certain amount of variability is bound to occur especially

with respect to the braking force applied on the runway.

• Topographical features : high altitude, deep valley, obstructions in approach

etc.

• Types of aircraft : since landing speed and distance required to reduce the speed to exit speed level will vary with the aircraft.
• Weather conditions : time required by the aircraft to slow down to the exit

speed is influenced by factors like wind, temperature etc.

Design of Exit taxiway

Following factors govern design of

exit taxiway.

• The most significant factor effecting turning radius is exit speed of aircraft.
• Slightly widened entrance of 30m gradually tapering to the normal width of taxiway is preferred . The wider entrance gives pilot more latitude in using exit taxiway

from following equation: R=

• Angle of turn of 30° to 45° can be negotiated in a satisfactory manner. The smaller angle are preferable because length of the curved path is reduced.
• For smooth and comfortable turn, the turning radius should be obtained

_V2

125f

• It is necessary to provide a compound curve for high turn off speeds of 65 to 95 kmph. It minimizes the tire wear on the nose gear and it is relatively easy to establish it in the fields.

Hence R2 > R1

• Aircraft approximates spiral but still compound curve is provided as it is relatively easier to establish in field and its shape is similar to spiral

• The following radius is found to be experimentally suitable:

• The length of larger radius curve can be roughly obtained from following relation: L1 = (0.28 𝑉)³/ CR2 (take C = 0.39)
• Sufficient sight distance must be provided which can be obtained from following relation : S.D. = (0.28 𝑉)² / 2d ( d = deacceleration in m/𝑠𝑒𝑐²)

PLANNING & DESIGN OF TERMIAL BUILDINGS

• The transition of passengers from ground to air occurs in the terminal area.
• The key feature of any terminal area is the terminal building.
• A building which is mainly used for the passengers, airline staff and administrative management. It may also provide accommodation for various operational activities like control tower, weather bureau etc.

Aprons

• It’s the Portion of an airport usually paved in front of Terminal building, for Parking, Loading & Unloading of Aircraft.
• Holding bays are also known as holding aprons, They are provided at busy airports near the runways.
• They hold Planes Before its Take-off to wait till the runway is cleared.

Size of Apron depends upon following factors:

1. Size of Gate position : It depends upon following factors
• Size of Aircraft and its minimum turning radius
• The manner in which aircraft enters

and leave the gate position.

• Aircraft parking configuration.

Number of Gate Position

• It depends upon the peak hourly aircraft movements and the time during which each aircraft remains in a gate position
• Number of gate positions can be calculated by following formula:

Number of gate positions = capacity of runway/(60 x 2) x average gate occupancy time

• For large aircrafts gate occupancy time is taken upto 60 minutes and for smaller aircrafts it can be taken as 10 minutes

Aircraft Parking system.

Pier or finger concept:

• The pier concept has an interface with aircraft along piers extending from the main terminal.
• Aircraft are usually arranged around the axis of the pier in a parallel or nose-in parking alignment.
• Each pier has a row of aircraft gate positions on both sides, with a passenger concourse along the axis which serves as the departure lounge and circulation space for both enplaning and deplaning passengers.

Satellite concept:

• The satellite concept consists of a building, surrounded by aircraft, which is separated from the terminal and is usually reached by means of a surface, underground, or above ground connector.
• The aircraft are normally parked in radial or parallel positions around the satellite.

Linear concept:

• The simple linear terminal consists of a common waiting and ticketing area with exits leading to the aircraft parking apron.
• It is adaptable to airports with low airline activity which will usually have an apron providing close-in parking for three to six commercial passenger aircraft

SATELLITE CONCEPT

LINEAR CONCEPT

Visual Aids

• Visual Aids are Land marks which are required so as to provide an assistance to the pilots.
• These aids ensures the smooth operating of the air craft
• Required both in good weather and bad weather as well as during day and night
• The runways of the conventional aircraft appears as long and narrow strip with straight sides and free of obstacle
• Marked in such a way they can be easily distinguishable from other areas

• The perspective view of the runways along with the landmarks

like horizon, runway edges, runway threshold and centreline of the runway are the most important elements for pilot to see.

▫ Centre line for aligning aircraft, horizon for flying, maintaining specific height from different elements like approach zone and similarly other things are needed to be identified.

​

• Hence, to enhance visual information land marks are painted in

​

standard formats using colour or by using lights

Visual Aids – Importance and Uses

• Avoids accidents during landing of aircraft
• Convey pilot the ground to air information
• Direct the pilot during landing

🞑Touch down points, lift off points etc are conveyed

• Enable the pilot to locate and identify a particular feature
• Grant safety to staffs and properties
• Maintain an orderly flow of aircrafts
• Helps during the takeoff and taxiing

Visual Aids

• These visual aids are available in different forms of

​

markings in the airport and airfield

▫

Airport markings

▫

Airport lighting

▫

Signage

Airport Markings

◻Markings are provided on any of the component of airport in different forms mentioned below

🞑Strips

🞑Patches

🞑Solid lines

🞑Hollow lines Etc.,

◻Arrangement can be inclined, perpendicular to runway or a component or any other shape

Airport Markings

• Airport markings can be divided into following groups

▫ Apron marking

▫ Landing direction indicator

▫ Runway marking

▫ Shoulder marking

▫ Taxiway marking

▫ Wind direction indicator

Apron Marking

• Certain guidelines are marked on the apron to help the pilots in maneuvering

the most critical aircrafts.

• Generally they are related to the path to be traversed during parking in or out operation near terminal location and
• How aircraft is going to take a turn etc.
• At what particular location it has to stop
• Where there can be a loading and unloading, everything is defined by using apron markings
• Yellow colour is used at such locations
• It should be fuel resistant as aprons are likely to be subjected to fuel spillage.

Landing Direction Indicator

• To indicate the landing direction an arrow or a Tee is placed at the center of a segmented circle

▫ Helps in identifying the runway strip and the direction from which they can land

▫ Shape is arrow, or Tee or circle with cutoff lines

• It is painted in orange or white colour
• It is lighted for viewing during night time
• It is fixed at a distant place

Segmented circle

Wind Direction Indicator

• The direction from which the wind blows is indicated by a wind cone
• It is placed in a segmented circle together with the landing

direction indicator

• It should be placed away from buildings so that it is not effected by eddies
• Panels forming segmented circle are gable roof shaped with a pitch of atleast 1:1

Wind direction Indicator

• Panels are painted white
• Length of wind direction indicator should not be less than 3.6m and its diameter at the larger end should not be less than 90cm
• It should be visible from a height of 30m
• It is painted with bands of colours like white and black, red and white, orange and white etc.

Runway Markings

• These are provided with different purposes like

▫ Runway center line marking

▫ Runway edge stripe

▫ Runway numbering

▫ Touch down or landing zone marking

▫ Threshold marking

🞄 Defines specific height by which aircraft should cross it

▫ Two or more parallel runways

Runway Marking

• Runway Centerline marking

▫ It is represented by a broken strip running along the entire length of runway

▫ Length of strip should be equal to length of gap or 30m whichever is higher

▫ Length of strip plus gap shall not be less than 50m and more than 75m

▫ The width of strip shall not be less than 90cm on precision approach runway and 30cm to 45cm on non-precision approach runway

Runway markings

Runway Markings

Runway Touch down markings

• It is provided in the touch down zone and consists of pair of rectangular

markings placed symmetrically about the runway center line

• These are 1.80m wide stripes spaced at 1.50m clear distance and are of

22.5m in length.

Runway Edge Stripe

• Runway edge strip consists of 2 stripes on along each edge of runway
• If width of runway is greater than 60m, the stripe should be located 30m

away from the runway centerline

• The thickness of stripes is normally 90cm

Runway Markings

Runway Threshold Markings

• Runway threshold markings consists

of a pattern of

longitudinal stripes of uniform dimensions placed symmetrically about the centerline of a runway

• They extend laterally within 3m of the edge of the runway
• They are 1.80m/3.60m wide with a spacing of 1.80/0.90m between them and are 45m long.
• Usually provided to clear the obstructions in the flight path

• Runway numbering

▫ The end of runway is marked with a number that indicates magnetic azimuth

🞄Angle measured in clockwise direction from north

▫ East end of East-West runway will be marked 27 (for 270 degree) and the west end is marked 9 for 90 degree

▫ Magnetic azimuth is marked to nearest 10 degree

• Two or more parallel runways

▫ If there are more than one runway in same direction following numbers are added to the azimuth numbers

🞄 2 parallel runways – L, R

🞄 3 parallel runways – L, C, R

🞄 4 parallel runways – L, R, L, R

🞄 5 parallel runways – L, C, R, L, R

Shoulder Marking

• Markings are in the form of yellow stripes , 90cm wide and 30m apart (15m at turnings)
• The markings extend up to a maximum 1.5m from the outer edge of shoulders
• Runway shoulders are marked with diagonal lines (45 degrees angle), whereas taxiways and holding apron shoulders are marked with stripes perpendicular to the direction of aircraft.

• Helps pilot in knowing whether they are moving towards runway or moving away from runway.
• Blast pad at the end of runway is marked with chevron or V shaped lines

▫This is the area or direction from which take off takes place.

Taxiway Marking

◻Center line of taxiway consists of 15cm wide continuous stripe of yellow colour

◻At intersection with runway end, the centerline of the taxiway is terminated at the edge of the runway

◻At all other intersections with the runway, the centerline of the taxiway extends up to the centerline of runway

🞑At other intersections with runway it will reach up to the centerline of runway and joins there.

• At the taxiway intersection, the centreline marking of the taxiway

continue through the intersection area

• For taxiway intersection where there is a need to hold the aircraft, a dashed yellow holding line is placed perpendicular to and across the centreline of both taxiways.
• At the intersection of runway with an exit taxiway, the taxiway markings are extended on to the runway parallel to the runway centreline, marking a distance of 60 meters beyond the point of tangency
• If a taxiway crosses a runway, the taxiway markings may continue

across the runway, but with interruption for the runway markings.

Holding position markings

Airport Markings

Closed runways or taxiways

• For temporarily closed runways or taxiways, yellow crosses are placed at the two ends that defines it is temporarily closed.
• If the runway is closed permanently yellow crosses are placed at both ends and also at 300m intervals, then threshold markings provided are erased.

FACTORS AFFECTING AIRPORT LIGHTING:

• Airport classification
• Amount of traffic
• Availability of power
• Nature of aircraft using the airport
• Type of night operation plans
• Type of landing surfaces provided
• Weather condition, etc.

• To achieve uniformity and to guide pilots for unfamiliar airports, colours and general arrangement of airport lights are standardized.
• Airport lights are kept clean, well-maintained, checked regularly for faulty bulbs and replacement.
• Tough and laborious job, major airport contains 30,000 lights
• Provision of emergency power supplies, which can take over in seconds in case of any power failure.

ELEMENTS OF AIRPORT LIGHTING:

•

•

•

•

•

•

•

•

•

Airport beacon

Approach lighting

Apron and hangar lighting

Boundary lighting

Lighting of landing direction indicator

Lighting of wind direction indicator

Runway lighting

Taxiway lighting

Threshold lighting

1) AIRPORT BEACON:

• Beacon- strong beam of light- used to indicate any geographical location- situated slightly above the horizontal- rotated to produce flashing light to an observer.
• It gives out white and green flashes in the horizontal directions 180◦ apart. Flashes are visible for the pilot from any direction of approach and it indicates the approximate situation of an airport equipped for the night operations.
• Rotates at six revolutions per minute- mounted at top of terminal building or hangar.

• Obstruction not cleared yet- then separate tower is provided for installation of rotating beacon.
• Code beacon- indicates light provided sufficiently high to clear all obstructions.
• It consists of two 500 watts bulb with green colour screen.
• Continuously flashes a Morse code signal designating the airport.

Airport Beacon Lighting:

APPROACH LIGHTING:

• Before runway begins- sequence of high-intensity lighting arrangement for a length of 900m.
• Helps pilots to check if the aircraft is centered correctly of not.
• Gives way to touchdown zone lights from threshold of the runway.
• Normally mounted on pedestals-varying heights-to accommodate any irregularities in ground- ensuring the lights themselves are in level.

Arrangements adopted for approach lightings:

• Calvert system
• ICAO system

1) Calvert system:

• Widely used in Europe and other parts of the world.
• Developed by E. S. Calvert in Great Britain.
• In this, there are six transverse rows of lights of variable length placed at a c/c distance of 150m.
• In this, the roll guidance is principally provided by the transverse rows of lights.

2) ICAO system:

• Known as centre-line configuration.
• In this, there is only one crossbar 300m from the threshold.
• In this, the roll guidance is provided by bars 4.2m in length, placed at 30m c/c on the extended centre-line of the runway and a single crossbar 300m from the threshold.
• The 4.2m long bars consists of 5 closely spaced lights to give the effect of continuous bar of light.

APRON AND HANGAR LIGHTING:

• These areas for are flood lit for the convenience in servicing and loading
• Flood-lighting system: constitutes a projector designed to be arranged to illuminate a surface.
• Mounted such a way that they do not cause glare in the eyes of the pilots, passengers and service personnel.
• Recommendation: flood lights should be placed at a height of not less than 12m above the pavement.

BOUNDARY LIGHTING:

• Entire boundary of the airfield is provided with lights at a c/c distance of about 90m with height of about 75cm from the ground.
• If fence is provided along the boundary, then these lights should be placed inside the fence at a distance of about 3m.
• For indicating hazardous approach, the boundary lights are provided with red marker lights

LIGHTING OF LANDING DIRECTION INDICATOR:

• The landing direction indicator is illuminated with suitable lighting arrangement so that the airport can be used at night also.

LIGHTING OF WIND DIRECTION INDICATOR:

• The wind direction indicator is illuminated by four 200 watts angle reflectors placed 1.8m above the top of the cone for providing a continuous lighting at any position of the cone.
• This arrangement grants the use of wind direction indicator at night and during bad weathers.

RUNWAY LIGHTING:

• After crossing the threshold, the pilot must complete a touchdown and roll out on the runway.
• The planning of runway lighting is carried out in such a way that the pilot gets enough information on alignment, lateral displacement, roll and distance.
• The lights are so arranged so that they form a visual pattern which the pilot can interpret easily.
• During night landings, flood lights were used in olden days. But now runway edge lights are adopted.

• Narrow gauge pattern- the most precise runway alignment which is widely used.
• It makes use of centre-line and touch down zone lights for operations in very poor visibility.
• Black hole effect: As the pilot crosses the threshold, and continues to look along the centre-line, the principal source of guidance, namely, the edge lights has moved far to each side in the peripheral vision. As a result, the central area appears black and the pilot is virtually flying blind for the peripheral reference information.

• This can be eliminated by adopting the narrow gauge pattern of the runway lighting, the central portion gets illuminated and the black hole effect is partly eliminated.
• The narrow gauge pattern forms a channel of light of 18m width up to 1140m from the threshold and beyond this distance, the closely spaced lights are placed along the centre-line of the runway extending up to the other end of the runway.

• All the lights provided on the runway are white in colour and of flush type, i.e. they do not project more than 1cm above the surface of pavement.
• The runway edge lights are of elevated type and they are white colour except for the last 400m if an instrument runway facing the pilot which are of yellow colour to indicate a caution zone.

TAXIWAY LIGHTING:

• The pilots have to manoeuvre the aircrafts on a system of taxiways to and from the terminal and hangar areas either after landing or on the way to take off
• The taxiway system is much complicated on large airports and therefore it is necessary to provide adequate lighting at night and at daytime when the visibility is very poor.

Design considerations to be applied to the visual aids for the taxiways:

• For normal exits- centreline terminated at the edge of the

runway.

🞄 At taxiway intersections, the lights continue across the intersection. They are placed at a distance of 6m to 7.5m along the straight length and 3m to 3.6m along the curves.

• The complete route from the runway to the apron should be easily identified.
• The edge lights should not project more than 75cm above the pavement surface.

• The exits from the runways should be so lighted that the pilots are able to

locate the exits 360m to 400m ahead of the point of turn.

• The intersection of taxiways and runways-taxiway crossings should be clearly marked.
• The lights on the tangent portion are placed not more than 60m apart and

the distance from the edge along the curves and the intersections to

facilitate easy identification. The spacing varies from 6m for radius 4.5m to 60m for a curve of 300m.

• There should be adequate guidance along the taxiway.

curve of

• The taxiway edge lights are blue and the taxiway centre lights are green.
• The taxiway should be clearly identified so that they are not confused

with the runways.

THRESHOLD LIGHTING:

• Identification of threshold- a major factor for decision of the pilot to land or

not to land

• For this reason, the region near the threshold is given with special lighting

treatment.

• At large airports: threshold is identified by a complete line of green lights extending across the entire width of the runway. They must be of semi-flash type, i.e. protruding not more than 12cm above the surface.
• At small airports, the threshold is identified by four lights on each side of the threshold. They can be of elevated type, i.e. protruding more than 12cm above the surface.
• The threshold lights in the direction if landing are green and in the opposite direction, they are red to indicated the end of the runway.

AIRPORT DRAINAGE:

• Airport drainage system is similar to street and highway drainage design.
• Airports are characterized by large areas of relatively flat gradient.
• Airports require prompt removal of surface and subsurface water.
• Hence, they need an integrated drainage system.
• Removal of water should be done from runways, taxiways, aprons, parking lots etc.

Aims of Airport Drainage:

• If the sub-surface drainage system is improper, it may moisten and weaken the subgrade and thereby reducing load bearing capacity.
• If surface drainage system is improper, it may results in ponding on pavements which causes nuisance for landing and take-off operations.
• It grants durability to pavements.
• It increases efficiency of the airport.
• It reduces the maintenance cost of airport.

BASIC REQUIREMENTS OF AIRPORT DRAINAGE SYSTEM:

1. The capacity of the drain pipe should be sufficient enough to carry surface water as well as ground water
2. The system should be designed in such a way that future extensions of runway, taxiway can be easily accommodated.
3. The system should grant speedy collection and removal of drained water.
4. The drain pipe material should be sufficient enough to withstand heavy concentrated loads of the aircraft.

Design Data

• A contour map showing of airport site and adjacent land showing all possible water courses contributing runoff. The contour interval should not be less than 0.6m.
• In addition, a more detailed grading and drainage plan, which shows the runway– taxiway system and other proposed airport features, should be prepared. The contour interval should not be less than 0.3m.
• The rainfall data such as frequency and intensity of storm of about 5-10 years

should be taken from metrological department.

• Centre line profiles of all runways, taxiways and apron area with necessary cross-section. Boring plans of soil strata along with ground water profile.
• Data on infiltration properties of soil encountered and actual run-off records for

drainage areas having similar characteristics of soil are gathered.