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Airport Engineering

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Syllabus

Functional areas of airports- Runways, Taxiways,

Aprons, Terminal buildings; Classifications of Airports;

Airport site selection; Design of Runway, Runway

orientation, Wind Rose diagram; Design of Taxiway and

Terminal building.

Books

1. Airport Planning and Design – Khanna, Arora & Jain

2. Airport Engineering – Rangawala

3. Air Transportation Planning & Design – Virendra Kumar & Satish

Chandra

4. Reference Book: Planning & Design of Airport – R. Horonjeff & F.X.

Mckelvey

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Introduction

1.1 Characteristics of Air Transportation

Advantages of Air Transportation

I. Speed:- High Speed among all the transport mode

II. Accessibility:- Open up any region that is inaccessible by other means of transport e.g. Hill area

III. Continuous Journey:- Movement is possible continuous over land and water unlike other modes

IV. Aerial Photography

V. Military use

VI. Encourage Trade and commerce:- More opportunities for business

VII. Agricultural spraying

VIII. Impact on Economic and Social life of country

IX. Safety:- Safer than road way travel. Fatal air accident is less than 20% of that of highway accident.

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Disadvantages are

1. High Cost

2. Noise Pollution

3. High Energy Consumption: Per passenger fuel consumption is 10 times more than bus

1.2 Air Transport in India & Abroad

• History of Development of Air Transport and its characteristics.

• Different Stages and modification in Air Transport mode.

• Present Scenario of worldwide Air Traffic.

• Development of Air Transportation in India.

History and Back Ground

Operational Development

Present Private and Govt. Participation in operation of Domestic as well as International Air Transportation

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1.3 Elements of Air Transport

Airport: It is an area of land and water which is to be regularly used for

commercial purposes for arrival, departure and movement

of aircrafts.

Aerodrome: Any defined area of land or water intended to be used for

arrival and departure of aircraft is called aerodrome.

Any airport is largely divided into three major components:

• The air side: this consists of airfield and landing take-off area

i.e. runway and taxiway

• The land side: this consists of terminal areas i.e. apron,

hanger, terminal building.

• Air traffic control: this consists control movement of aircrafts

in airspace surrounding the airport.

Airport Engineering deals with first two components

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C

A

B B BB

E

F

D

A : Runway

B: Taxiway

C: Apron

D: Hanger

E: Terminal Building

F: Car parking Zone

Fig. Schematic Diagram of an airport

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Runway:

• Long and comparatively narrow strip of land which is used for landing and take-off of aircraft along its lengths.

• Paved.

• More than one runway.Taxiway:

• Access of the aircraft from runway to apron or hanger.• Speed of the aircrafts are less than runway.• Less thick pavement.

Apron:• Paved portion in front of the terminal building or adjacent to

hanger.• Space for parking of aircrafts.• Size of the apron depends upon aircraft volume• Paved space provided near the runway is known as holding

apron.• Apron exclusively used for fueling purpose is known as

fueling apron

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Hanger:

• Space for servicing, overhauling and repairing of aircrafts

• Important airports may have more than one hanger

Terminal Building:

• Building complex mainly used for passengers, airliners and airport administration facility.

• Passenger facilities for convenient and direct access to ground

transportation and parking area.

An airport encompasses a wide range of activities which have

different and conflicting requirements. As they are

interdependent, a single activity may limit capacity of entire

complex.

The airport activity system is shown in the next slide

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Enroute Airspace

Terminal Airspace

Runway

Holding Apron Exit Taxiway

Taxiway

Apron/Gate Area

Terminal Building

Vehicular Circulation Parking

Airport Ground Access System

Airfield Surface System

Air side

Land side

Aircraft flowPassenger flowFig. Components of the airport

system for a large airport

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1.4 Classification of an Airport

1.4.1 International Civil Aviation Organization (ICAO)

– Most important international agency concerned with airport

development.– Specialized agency of UNO with head quarter at Montreal,

Canada.– 169 nations are members.

– The objective of ICAO are:

• Safe and orderly growth of international civil aviation.

• Aircraft design and operation for peaceful purpose.

• Development of airways, airports and air navigation facilities.

• Safe, regular, efficient and economic air transportation.

• Rights of the contracting nations are fully respected.

• Promotion of all aspects including safety of flight of

international civil aeronautics.

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The document – “Aerodromes, Annex 14 to the convention on

International Civil Aviation” issued by ICAO provides

international design standards and recommended practices

applicable to all international airports.

ICAO uses a two-element code to clarify geometric design

standards at an airport. The code element consist of a numeric

designator and an alphabetic designator. Aerodrome code

numbers 1 through 4 classify the length of runway available or

the reference field length.

Aerodrome code letters A through E classify the wingspan and

outer main gearwheel-span for the aircraft for which the airport

has been designed.

This aerodrome reference code is shown in Table 1.0

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Reference Field Length: Actual Runway takeoff length converted to an

equivalent length at MSL, 150C, and 0 percent gradient.

Wing Span: Distance between outside of two wings of the aircraft.

Outer main gear wheel span: Distance between outside edges of tyres

on the main gear wheel.

Table 1.0 ICAO Aerodrome Reference Codes

Aerodrome Code No.

Reference field length (m)

Aerodrome Code Letter

Wing Span (m)

Outer main gear wheel span (m)

1 <800 A < 15 < 4.5

2 800 - <1200 B 15 - < 24 4.5 - < 6

3 1200 - <1800 C 24 - < 36 6 - < 9

4 ≥1800 D 36 - < 52 9 - < 14

  E 52 - < 65 9-< 14

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1.4.2. Federal Aviation Administration (FAA)

This is an agency which governs air transportation including airports in

United States. It develops and establishes standards, government

planning methods and procedures, airport design, construction

management, operation and maintenance. It clarifies airports for

geometric design purposes based upon airport reference code.

Utility Airport: Utility airports serves and accommodate small aircraft

with maximum take off weight of 12,500lbs. or less.

Transport Airport: Transport airports can accommodate large aircraft

with maximum take off weight in excess of 12,500 lbs.

FAA also defines five aircraft approach categories. The approach

category is defined by aircraft approach speed which is defined as 1.3

times the stall speed in the landing configuration of the aircraft at the

maximum certified landing weight.

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Airport Approach Category Aircraft approach Speed (Knot) Airport Category

A <91 Utility Airport

B 91 - <121 Utility Airport

C 121 - <141 Transport Airport

D 141 - <166 Transport Airport

E ≥ 166 Transport Airport

1 Knot = 1.87 km/hr.

Table 2.0 FAA Aircraft Approach Category Classification

Airplane Design group Aircraft Wing Span (ft.) Typical Aircraft

I < 49 Beech Bonanza A 35 Learjet 25

II 49 <79 DeHavilland DHC-5 Gulfstream II

III 79 - <118 Boeing 737, Martin-04

IV 118 - <171 Boeing 757, Lockheed 1011

V 171 - < 214 Boeing 747-400

VI 214 - < 262 Lockheed C5A

Table 3.0 FAA Airplane Design Groups for Geometric Design of Airport

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1.4.3. Govt. of India, Dept. of Civil Aviation Classification.

I. a) Central Govt. Aerodrome

b) Privately owned licensed aerodrome

II. a) State Govt. Aerodromes maintained in a serviceable condition

b) State Govt. Aerodromes maintained in a serviceable condition

iii. Air force aerodrome available for limited civil use

Airport configuration The airport configuration is the number and orientation of

runways and the location of the terminal area relative to the runways.

The number of runways provided at an airport depends on the volume of traffic.

The orientation of these runways depends to a large extent on the direction of the prevailing wind patterns in the area, the size and shape of the area available for airport development, and land-use or airspace restrictions in the vicinity of the airport

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Runways

In general, runways and connecting taxiways should be arranged so as to-

• Provide adequate separations between aircraft in the air traffic pattern.

• Cause the least interference and delay in landing, taxing, and takeoff operations.

• Provide the shortest taxi distance possible from the terminal area to the ends of the runways.

• Provide adequate taxiways so landing aircraft can exit the runways as quickly as possible and follow the shortest possible routes to the terminal area.

• At busy airports, holding or run-up aprons should be provided adjacent to the takeoff ends of the runways – these aprons should be designed to accommodate three or possibly four aircraft to bypass one another.

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Taxiways

The principal function of taxiways is to provide access between

runways and terminal area and service hangers

• Taxiways should be arranged so that aircraft which have just landed

do not interfere with aircraft taxiing to take off.

• At busy airports where taxiing traffic is expected to move

simultaneously in both directions, parallel one-way taxiways should

be provided .

• Taxiway should be located at various points along runways so that

landing aircraft can leave the runways quickly to clear them for use

of other aircraft – commonly known as exit taxiways.

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Runway Configuration

The basic runway configuration are

• Single runway.

• Parallel runways.

• Dual-lane runways.

• Intersecting runways.

• Open or V-runways.

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RUNWAY ORIENTATION

• Runway is usually oriented in the direction of prevailing wind. If the take off is performed in the direction opposite to the direction of wind flow, greater lift on the wings of the aircraft is available.

• Due to the force applied by the wind, the aircraft can rise above the ground much earlier and therefore a shorter length of runway is required.

• This wind, directly opposite to the movement of the aircraft, is called head wind.

• During landing the wind provides a breaking effect and the aircraft comes to a stop within a shorter distance requiring a shorter length of runway.

• Thus, shorter runway length is required if the landing or take-off operation is performed along the head wind direction

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Wwsinθθ

wcosθ

wTakeoff

Landing

w Wind Direction

However, this is not always possible to have the wind blows in the direction of runway as the direction of wind is not same through out the year.

When the wind direction meets the runway at angle θ, its components along the runway centre line will be wcosθ and perpendicular to the runway centre line will be wsinθ. This perpendicular components of wind is referred as Cross Wind.

This cross wind components interrupts the landing and take off operation of the aircraft on runway. The excessive cross wind may put off the aircraft away from runway.

Therefore the runway or system of parallel runway should be directed in such a way that the cross wind component does not cross the specified limit most of the time in a year.

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The percentage of time in a year during which the cross wind components remain within the specified limit is called wind coverage or usability factor of airport.

ICAO recommended a minimum wind coverage of 95%.

The permissible cross wind components on different runway length as recommended by ICAO are

Reference Length 1500m or over

1200m – 1499m Less than 1200m

Maximum cross wind component

37 km/hr 24 km/hr 19 km/hr

This 95% criterion suggested by ICAO is applicable to all conditions of weather. When a single runway or a set of parallel runways cannot be oriented to provide the required wind coverage, one or more cross wind runway should be provided.

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The period during which wind blows at a velocity below 6.4km/hr is called calm period. This intensity does not influence the aircraft operation.

Maximum allowable cross wind component depends upon size of aircraft, wing configurations and pavement surface.

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WIND ROSE DIAGRAM

• The wind data and its direction, duration and intensity are

represented by a diagram called ‘wind rose’.

• This wind rose is used to analyze the wind data graphically to determine the best runway orientation.

• The wind data should be collected preferably for a period of 10 years and at least for 5 years.

• The wind rose diagram are of two types and there are two methods to determine the runway orientations.

• The wind data for preparation of wind rose diagram should provide:

a) Direction of wind preferably in 16 directional segments

each covering 22.50. and

b) Duration of wind in % of the total time in different velocity group and at least three group should be taken starting from 6.4 kmph.

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Table: Typical Wind Data: Percentage of time that Winds Come from Particular Directions at Various Velocities in All Weather Conditions

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NNNE

NE

ENE

E

ESE

SE

SSES

W

WIND ROSE TYPE IIn this method the duration and direction of wind are used, but data on velocity of wind is not required

This is not very accurate method.

The radial lines indicate the wind direction and the duration is marked in this radial line to some suitable scale.

All plotted lines are joined by straight lines. The best runway orientation is usually along the direction of the largest line on the wind rose diagram.

In the figure the best orientation is along EW direction.,

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Wind Rose Co-ordinate system Cross wind components template showing limits of 15 mi/h

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• The type II wind rose diagram shows information of wind on

direction, duration and intensity.

• This diagram is used for orientation of runway.

• The wind rose diagram consists of a number of concentric

circles, each circle represents the wind intensity to same scale.

• The circles are divided into number of segments, preferably 16

segments, each covering 22.50.

• Each segment represents a direction of wind flow.

• The duration of wind flow as a percentage of time in a year is

noted in segment representing the respective direction of wind

flow.

WIND ROSE TYPE II

29Wind rose type II

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RUNWAY ORIENTATION

Step I : Draw the equi-spaced parallel lines on a transparent paper

strip. The middle line represents the runway centre line and the

distance between it and each of the out side lines is equal to the

allowable cross wind component.

Step II : Place the transparent strip on the wind rose so that the middle

line passes through the centre of the wind rose.

The procedure for determining the orientation of runway with the

help of wind rose diagram is described in the following steps

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Step III : Rotate the strip with respect to the pivot until the sum of the

percentage between the outside lines is a maximum. When the strip

covers only a fraction of a segment, corresponding fractional part of

the percentage shown should be used. The sum of percentages

between the out side lines indicate the percentage of time that the

runway with the proposed orientation will conform with cross wind

standard.

Step IV : Note the direction of runway and calculate the wind coverage.

RUNWAY ORIENTATION

32Wind coverage for runway 9-27

33Wind coverage for runway 3-21

34Wind coverage for runways 9-27 and 3-21

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1. Plot the wind rose diagram under VMC

2. Determine the best orientation of primary runway at this airport. Permissible cross wind component 15km/hr

Wind Data for day light hours for visual meteorological conditions for an airport