➼ Airport:- any area of land or water used or intended for landing or takeoff of aircraft including appurtenant area used or intended for airport buildings, facilities, as well as rights of way together with the buildings and facilities.

Multiple Choice Question ➼ Airport Engineering

Typical Layout of Airport.

Advantage/Role of Air transportation

• Improves accessibility to otherwise inaccessible areas
• Provides continuous connectivity over land and water (no change of equipment)
• Saves productive time, spent on journey
• Increase the demand of specialized technical skill workforce
• Adds to the foreign reserve through tourism
• Speed: Modern jet can travel at 1000 km/h
• Promotion of trade and commerce
• Military use
• Relief and rescue operations
• Aerial photography
• Agricultural spraying
• Safety: safe mode of transport.

Disadvantages of air transport

• Heavy funds are required, not only initially but also during operation
• Operations are highly dependent up on weather conditions.
• It needs highly sophisticated machinery:
• Adds to the outward flow of foreign reserve
• Noise pollution
• Safety provisions are not adequate
• Specific demarcation of flight paths and territories is essential.
• High energy consumption

# Geometric Standards for Elements of Airport

Standards are for

• Runway
• Taxiway
• Apron

➼ Runway:- Parameters of runway are:

• Length
• Width
• Sight distance
• Gradient & Change in Gradient
• Transverse Gradient Runway Intersection
• Runway Clearance

The following factors most strongly influence required runway length.

• Performance characteristics of aircraft using runway length.
• Landing and takeoff gross weights of aircraft
• Elevation of airport
• Average maximum air temperature at the airport
• Runway gradient

• Correction for elevation and temperature should be done
• Maximum width of landing strip:
  • Non instrumental runway: 150 m
  • Instrumental runway: 300 m

➼ Basic length of runway character

It is the length of runway under the following conditions:

• Airport altitude is at sea level
• Airport temperature is 15 0 Celsius
• Runway is level in longitudinal direction
• No wind is blowing on runway
• Aircraft is loaded to its full capacity.

➼ Declared distances

• Take-off run available (TORA): the length of runway declared available and suitable for the ground run off an aero plane taking off.

• Take off distance available (TODA):    the length of takeoff run available plus the length of the clearway, if provided.

• Accelerate stop distance available (ASDA): the length of the take-off run available plus the length of the stopway, if provided.

• Landing distance available (LDA): the length of runway which is declared available and suitable for ground run of an airoplane landing.

# Width of Runway

The width of a runway should not be less than the approximate dimension specified in the table below. The factors affecting the width of runway are:

• Deviation of an aeroplane from the centerline at touchdown.
• Cross wind condition
• Runway surface contamination (snow, rainfall ice etc.)
• Rubber deposit
• Crab landing approached used in cross-wind conditions
• Approach speeds used
• Visibility
• Human factors

# Longitudinal slopes

The slopes computed by dividing the differences between the maximum and minimum elevation along the runway centerline by the runway length should not exceed:

• 1 % where the code number is 3 or 4
• 2% where the code number is 1 or 2

Along no portion of a runway should the longitudinal slope exceed:

• 1.25% where the code number is 4, except that for the first and last quarter of the length of the runway the longitudinal slope should not exceed 0.8%.
• 1.5 % where the code number is 3, except that the first and last quarter of the length of a precision approach runway II or III the longitudinal slope should not exceed 0.8%.
• 2 % where the code number is 1 or 2.

➼ Longitudinal slope changes

Where slope changes cannot be avoided, a slope change between two consecutive slopes should not exceed:

• 1.5 % where code number is 3 or 4;
• 2% where code number is 1 or 2

The transition from one slope to another should be accomplished by a curved surface with a rate of change not exceeding:

• 0.1 % per 30 m. (R min of 30 000) where code number is 4
• 0.2% per 30 m ( R min 15 000) where code number is 3.
• 0.4% per 30 m (R min 7 500) where code number is 1 or 2.

# Sight distance

Where slope changes cannot be avoided, they should be such that there will be an unobstructed line of sight from:

• Any three m above a runway to all other points 3 m above the runway within a distance of at least half the length of the runway where the code letter is C, D or E.
• Any point 2 m above a runway to all other points 2 m above the runway within a distance at least half the length of runway where code letter is B; and
• Any point 1.5 m above a runway to all other points 1.5 m above the runway within a distance of at least half the length of runway where the code letter is A.

➼ Distance between slope changes

Undulation or appreciable change in slopes located together along the runway should be avoided. The distance between the points of intersection of two successive curves should not be less than:

1. The sum of the absolute numerical values of the corresponding slope changes multiplied by the appropriate values as below:
   1. 30 000 m where the code number is 4
   1. 15 000 m where the code number is 3 and
   1. 5 000 m where the code number is 1 or 2
2. 45 m;

Whichever is greater?

# Transverse slope

To promote the rapid drainage of water, the runway surface should, if practicable, be cambered except where a single cross fall from high to low in the direction of the wind most frequently associated with rain would ensure rapid drainage. The transverse slope should ideally be:

• 1.5 % where the code letter is C, D, E or F
• 2% where the code letter is A or B

But in any event should not be exceed 1.5 % or 2 %. As applicable, nor be less than 1 % except at runway or taxiway intersections where flatter slopes be necessary.

# Runway shoulder

Runway shoulder must be provided to ensure a transition from the full strength pavement to the unpaved strip of runway. The paved shoulder protects the edge of the runway pavement, contribute to the prevention of soil erosion by jet blast and

mitigate foreign object damage to jet engines. Runways shoulder should be provided for a runway where the code letter is D or E and the runway width is less than 60m. Runway shoulders should be provided where the code letter is F.

The runway shoulders should extend symmetrically on each side of the runway so that the overall width of the runway and its shoulders is not less than 60 m for letter E and 75 m for code letter F.

# Slopes

The surface of the shoulder that abuts the runway should be flush with the surface of the runway and its transverse downward slope should not exceed 2.5 %.

# Runway strip

A runway strip extends laterally to a specified distance from the runway center line, longitudinally, before the threshold, and beyond the runway end. It provides an area clear of objects which may endanger aeroplanes.

The strip includes a graded portion which should be so prepared as to not cause the collapse of the nose gear if an aircraft should leave the runway. There are certain limitations on the slopes permissible on graded portion of the strip.

A strip should before the threshold and before the end of the runway or stopway for a distance of at least:

• 60 m where the code number is 2, 3, or 4.
• 60 m where the code number is 1 and the runway is an instrument one;
• 30 m where the code number is 1 and runway is a non-instrument one. Width:

A strip including a precision approach runway shall, wherever practicable, extend laterally for a distance of at least:

• 150 m where the code number is 3 or 4 and;
  • 75 m where the code number is 1 or 2.

A strip including non-precision approach should extend laterally to a distance of at least:

• 150 m where the code number is 3 or 4;
• 75 m where the cod number is 1 and 2

On each side of the centerline of the runway and its extended centerline through the length of the strip

A strip including a non-instrument runway should extend, on each side of the centre line of the runway and its extended centre line throughout the length of the strip, for a distance of at least:

• 75 m where the code number is 3 or 4
• 40 m where the code number is 2; and
• 30 m where the code number is 1.

# Objects

An object, other than equipment or installation required for air navigation purposes, situated on a runway strip which may endanger aeroplanes should be regarded as an obstacle and should, as far as practicable, be removed. Any equipment or installation required for air navigation purposes which must be

located on the runway strip should be of minimum practicable mass and height, frangibly designed and mounted, and sited in such a manner as to reduce the hazard to aircraft to a minimum.

No fixed object, other than visual aids required for air navigation purposes, shall be permitted on a runway strip:

• within 77.5 m of the runway centre line of a precision approach runway category I, II or III where the code number is 3 or 4 and the code letter is F; or
• within 60 m of the runway centre line of a precision approach runway category I, II or III where the code number is 3 or 4; or
• within 45 m of the runway centre line of a precision approach runway category I where the code number is 1 or 2.

# Taxiway and Apron

Maximum capacity and efficiency of an aerodrome are realized only by obtaining the proper balance between the need for runways, passenger and cargo terminals, and aircraft storage and servicing areas. These separate and distinct aerodrome functional elements are linked by the taxiway system.

Planning principles of taxiway

• taxiway routes should connect the various aerodrome elements by the shortest distances, thus minimizing both taxiing time and cost;
• taxiway routes should be as simple as possible in order to avoid pilot confusion and the need for complicated instructions;

• straight runs of pavement should be used wherever possible. Where changes in direction are necessary, curves of adequate radii, as well as fillets or extra taxiway width, should be provided to permit taxiing at the maximum practical speed

• taxiway crossings of runways and other taxiways should be avoided whenever possible in the interests of safety and to reduce the potential for significant taxiing delays;

• taxiway routings should have as many one-way segments as possible to minimize aircraft conflicts and delay. Taxiway segment flows should be analysed for each configuration under which runway(s) will be used;
• the taxiway system should be planned to maximize the useful life of each component so that future

Taxiway Curve

Changes in direction of taxiways should be as few and small as possible.

# Holding bays and other bypasses

• Holding bays: A defined area where aircraft can be held or bypassed.
• a detailed example of a holding bay, located at the taxi-holding position.
• Dual taxiways. A second taxiway or a taxiway bypass to the normal parallel taxiway.
• Dual runway entrances. A duplication of the taxiway entrance to the runway.

# Apron

An apron is a defined area intended to accommodate aircraft for purposes of loading and unloading passengers, mail or cargo, fuelling and parking or maintenance. The apron is generally paved but may occasionally be unpaved; for example, in some instances, a turf parking apron may be adequate for small aircraft.

Types

• Passenger apron: The passenger terminal apron is an area designed for aircraft manoeuvring and parking that is adjacent or readily accessible to passenger terminal facilities. This area is where passengers board the aircraft from the passenger terminal. In addition to facilitating passenger movement, the passenger terminal apron is used for aircraft fuelling and maintenance as well as loading and unloading cargo, mail and baggage. Individual aircraft parking positions on the passenger terminal apron are referred to as aircraft stands.
• Cargo terminal apron: Aircraft that carry only freight and mail may be provided a separate cargo terminal apron adjacent to a cargo terminal building. The separation of cargo and passenger aircraft is desirable because of the different types of facilities each requires both on the apron and at the terminal
• Remote parking apron: In addition to the terminal apron, airports may require a separate parking apron where aircraft can park for extended periods.
• Service hanger apron: A service apron is an uncovered area adjacent to an aircraft hangar on which aircraft maintenance can be performed, while a hangar apron is an area on which aircraft move into and out of a storage hangar.
• General aviation aircraft, used for business or personal flying, require several categories of aprons to support different general aviation activities.

# Correction for Elevation, Temperature and Gradient

➼ Correction for Elevation

As the elevation increases, the air density reduces. It reduces the lift on the wing of the aircraft and 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 300 m rise in elevation above mean sea level.

➼ Correction for temperature

The rise in airport reference temperature has the same effect as that of the increase in elevation. Airport reference temperature (Tr) is defined as the monthly mean of average daily temperature (Ta) for the hottest month of the year plus one third the difference of this temperature (Ta) and monthly mean of the maximum daily temperature (Tm) for the same month of the year.

ICAO recommends that the basic length of the runway after having been corrected for elevation should be further increased at the rate of 1 % for every 1° rise of airport reference temperature above the standard atmospheric temperature (Ts) at the elevation. The temperature gradient of the standard atmospheric from the mean sea level to the altitude at which temperature becomes 15° C is -0.0065° C per meter.

Check for total correction for elevation and temperature:

It the total correction (elevation and temperature) exceeds 35% the basic runway length, these corrections should then be checked up by conducting specific studies.

➼ Correction for Gradient

Steeper gradient results in greater consumption of energy, and longer the runway length is required for attaining the ground speed.

ICAO does not recommend on this correction. FAA recommends that the runway length after having been corrected for elevation and temperature should be further increased at the rate of 20% for every 1% of effective gradient.

Effective gradient is defined as the maximum difference in elevation between the highest and lowest points of runway divided by the total length of runway.

Some organizations related to the civil aviation

• International Civil Aviation organization-ICAO
• Established in 1944 as a result of Chicago convention Headquarter is in Montreal, Canada.
• It is made up of an assembly, a council of limited membership with various subordinate bodies and a secretariat.
• Assembly composed of representatives from all contracting states, is the sovereign body of ICAO
• The council the governing body which is elected by the assembly for a three year term is composed of 36 states.
• ICAO aims and objectives are to develop the principles and techniques of international air navigation and to foster the planning and development of international air transport so as to
• Insure the safe and orderly growth of international civil aviation throughout the world.

• Encourage the arts of aircraft design and operation for peaceful purposes
• Encourage the development of airways, airports, and air navigation facilities for international civil aviation
• Meet the needs of the peoples of the world for safe, regular, efficient and economical air transport.

Strategic objectives for the period of 2005-2010:

• Safety
• Security
• Environmental protection
• Efficiency
• Continuity
• Rule of law

• Federal Aviation Agency-FAA
• Civil Aviation Authority of Nepal-CAAN
• Airport Authority of India

Classification of Airports

There are different classifications by the related organizations such as ICAO, FAA etc.

#Based on take-off and landing

• Conventional take-off and landing airport (runway length > 1500 m.
• Reduced take-off and landing airport (runway length 1000 to 1500m)
• Short take-off and landing airport (runway length 500 to 1000m)
• Vertical take-off and landing airport (operational area 25 to 50 sq. m.)

#Based on the Geometric design (ICAO)

• It employs aerodrome reference code, it consists of length of runway available
  • Classified using code number 1 through 4
  • Aircraft wing span and outer main gear wheel span
    • Classified using letters A through E
  • ICAO classification based on wing span and outer main gear wheel span

#Based on function

• Civil aviation airports
  • Domestic airports
  • International airports
  • Combination of international and domestic

#Military aviation airports

Military purposes.

Aircraft Component parts

• Engine
• Propeller
• Fuselage
• Three control
• Tricycle under carriage

1. Engine

Engine is required to provide the force for propelling the aircraft through the air. According to the method of propulsion aircraft engine can be classified as:

➼ Piston engine:

It is powered by gasoline fed reciprocating engine and is driven by propeller or airscrew. Engine rotates a shaft with a considerable amount of torque. Propeller is mounted on the shaft to absorb the torque. Rotating propeller attains its rated speed, huge masses of air is hurled rearwards thereby pulling the aircraft forward and creating lift on the wing. They are suitable to operate at low altitudes and moderate speed. They have cooling problem also.

➼ Jet engine:

advantages of jet engines are

• they are free from vibration

• Simplicity of operation (no transmission or conversion mechanism is required)

• No radiators required

• No spark plugs are required

• No carburetors

• Less consumption of lubricants

a. Turbo Jet: to start the machine, the compressor is rotated with motor. As the compressor gains its rated speed, it sucks in air through the air intake and compresses it in the compression chamber. The air is ignited here by fuel. The expanding gasses pass through the fan like blades of turbine. The hot gasses escape through the tail pipe which becomes smaller in diameter and this hot gas having velocity, give a forward thrust to the engine.

b. Turbo Prop: It is similar to the turbo jet engine except that propeller is provided in it. Turbine extracts enough power to drive both the compressor and propeller.

c. Ram Jet: It has no moving parts. It must be operated at high speed It requires the assistance of other types of power plant to reach the operating speed. The heated air expands and rushes out of the exhaust nozzle at high velocity creating jet thrust.

➼ Rocket engine:

It produces thrust in the same way as the ram jet engine except it does not depen upon the atmospheric oxygen. There is no limit on altitude.

An airplane can be single engine or multi engined. Single engine usually mounted at the nose of the fuselage. In two or four engined aircraft they usually housed in the leading edge of the aircraft.

2. Fuselage

It is main body of the aircraft and provides space for the power plant, fuel, cockpit, passenger, cargo etc.

3. Wings

Wings are required to support the machine in the air, when the engine has given forward speed.

4. Three controls

There are three axes about which an aircraft in space may move to control these movements an aircraft is provided with three principal controls:

• Elevator: elevator consists of two flaps capable of moving up and down through an angle of 50-60 degree. They are hinged to a fixed horizontal surface at the extreme rear end of fuselage. It controls the pitch of the aircraft.
• Rudder: It consists of a flap hinged to a vertical line provided at the tail end of fuselage. It is utilized for turning (or yawing) movement of the aircraft. It works just a boat is steered in water.

• Aileron: it is hinged flap in the trailing edge of the wing. It is for rolling movement control.

X axis: rolling movement; Y axis: Pitching; Z axis: Yawing

5. Tricycle under-carriage

Tricycle undercarriage if for supporting the aircraft while it is in contact with the ground. Functions:

• To absorb landing shocks

• To enable the aircraft to maneuver on the ground

Types:

• Single wheel assembly
  • Dual wheel assembly
  • Dual wheel assembly in Tandem

# Aircraft Characteristics

• Engine type and propulsion

• Size of aircraft

• Minimum  turning radius

• Minimum circling radius

• Speed of aircraft

• Capacity of the aircraft:- baggage, cargo, and fuel accommodated in the aircraft.

• Aircraft weight & wheel configuration

• Jet Blast

• Fuel spillage

Lighting

# Aviation System Planning

Aviation system planning is a process aimed at translating goals and policies into programs that would guide the evolution of the aviation system.

Components of the aviation system:

• Airways
• Airports
• Airlines
• Aircrafts
• General aviation
• Air passenger
• Operating environment

The aim of the airport system planning is to determine and plan for the scope of development of individual airports within a system in accordance with a scheme which is most likely to fit the individual facilities into an optimal overall development pattern.

Level of planning:

• Strategic planning examines long-term structures and determines how well various structures fit with indentified goals and objectives. A strategic plan sets out procedure to follow which will lead to an optimal long term structure.
• Tactical Planning: determines short-term and medium term courses of action which best fit into overall strategic plans and goals. Furthermore, tactical plans identify the best manner of carrying out these short and medium term courses of action.

# Data base for airport system Planning

➼ Traffic data:

• Route and city pair specific data, including origin/destination flows.
• Airport specific data
• Traffic by other modes especially in short haul situations.

➼ Demand characteristics:

• Origin destination demand
• Trip purpose distributions for cargo demands
• Commodity classifications for cargo demands
• General aviation activity demand

➼ Airport data:

• Financial results
• Facilities inventories
• Capacity
• Temporal traffic patterns, including hourly distributions
• Airlines served
• Access traffic conditions
• Safety records
• Weather conditions
• Traffic operation patterns

➼ Supply data:

• City pair available capacity
• Schedule and fares for passengers and cargo
• Load factor prevailing
• Airline operating cost data

➼ Socio economic data:

• Economic studies for regional economic plans if available
• Population and demographic characteristics and forecasts, if available
• Income characteristics and consumption patterns
• Foreign and tourism trade patterns

# Airport Master Plan

Specific objectives of airport Master Plan:

• Provide effective graphic representation of the future development of airport and future lan-use in the vicinity of the airport.

• Establish a realistic schedule for the implementation of the development proposed in the plan, particularly for short term capital implement program.

• Proposing an achievable financial plan to support the scheduled implementation program.

• Justifying the plan technically and procedurally through a thorough investigation of concepts and options of a technical, economic, or environmental nature.

• Presenting for public consideration in a convincing candid manner, a plan which adequately addresses the issues and satisfies local and national regulations.
• Documenting policies and future aeronautical demand and reference in municipal deliberations on spending, debt incurrence and land –use controls.
• Setting the stage and establishing the framework for a continuing planning process. Such process would monitor key conditions and adjust plan recommendations if required by changed circumstances.

# Airport Site Selection

Suitable site for airport depends upon the class of the airport. Factors to be considered for a suitable airport site are:

• Operational capability: airspace considerations, obstructions, weather etc.
• Airport use: military, civil, etc.
• Proximity to other airport: minimum spacing between two airports:
  • Airport for general aviation under VFR 3.2 km
• • For two piston aircraft VFR: 6.4 km
• • Piston engine IFR: 25.6 km
  • Jet engine aircraft: 160 km.
• Ground accessibility: normally it should not exceed 30 minute drive form the city. It is desirable to locate airport adjacent to the highway.
• Topography: hill top is most suitable
• Visibility: free from fog, smoke haze etc.
• Wind: runway orientation should be: landing and takeoff is done by heading into wind. Smoke from city and industry should not blow over the airport.
• Noise nuisance: landing and takeoff path should not pas over the residential or industrial areas.
• Grading, drainage and soil characteristics
• Future development

# Airport Capacity

The growth in air travel is outstripping the capacity of airport and air traffic control system, resulting in increasing congestion and delay.

The consequences for the air transport industry and traveling public are greater inconvenience, higher costs, declining quality of services and concerns about diminishing safety.

The purpose of capacity analysis is to:

• Measure objectively the capacity of various components of an airport system for handling projected passenger and aircraft flows.

• Estimate the delays experienced in the system at different levels of demand.

Note:- The capacity analyses make it possible for the airport planner to determine the  number of runways, to identify potential configurations, and to compare alternative design.

➼ Capacity, Demand and Delay

The term “capacity” refers to the ability of a component of airfield to accommodate aircraft. It is expressed in operations (arrivals and departures) per unit of time, typically in operations per hours.

Thus, the hourly capacity of the runway system is the maximum number of aircraft operations that can be accommodated in one hour under specified operating conditions.

Capacity depends on a number of prevailing conditions, such as visibility, air traffic control, aircraft mix, and type of operations.

Capacity should not be confused with demand. Capacity refers to the physical capability of an airfield and its components. It is measure of supply, and it is independent of both the magnitude and fluctuation of demand and the amount of delay to aircraft.

Delay, however is dependent on capacity and the magnitude and fluctuation in demand. One can reduce aircraft delays by increasing capacity and providing a more uniform pattern of demand.

# Runway capacity

Runway capacity is normally the controlling element of the airport system capacity.

There are large numbers of factors that influence the capacity of runway system:

a. Air traffic control: FAA specifies minimum vertical, horizontal, and lateral separations for aircraft in the interests of air safety. Since no two airplanes are allowed on the runway at the same time, the runway occupancy time may also influence the capacity.

Example: A runway serves aircraft that land a speed at 165 mph while maintaining the minimum separation of 3 nautical miles as specified by FAA. The average runway occupancy time for landing aircraft is 25 seconds. Determine maximum arrival rate pf the airport. The minimum spacing is (3X6076

= 18228 ft.) in terms of time the minimum arrival spacing is 18228 /(165X5280/3600)= 75 sec. The maximum rate of arrival that can be served by the runway is no more than (3600/75) = 48 arrivals per hour.

b. Characteristics of demand: capacity of runway depends on aircraft size, speed, maneuverability, and braking capability, as well as pilot technique.

c. Environmental conditions: the most important environmental factors influencing capacity are visibility, runway surface conditions, winds, and noise abatement requirements.

d. The layout and design of runway system: for the airport planner, layout and design features comprise the most important class of factors that affect runway capacity. Principal factors in this class include:

• Number, spacing, length and orientation of runways.

• The number, locations, and design of exit taxiway

• The design of ramp entrance

➼ Determination of runway capacities and delay

• Empirical approaches

• Queuing models

• Analytical approaches

• Computer simulation

# Airport Layout

Layout of an airport is dependent upon a number of factors the most important are:

• Number and orientation of runways
• Number of taxiways
• Size and shape of aprons
• The area and shape of land
• Topography and site soil conditions
• Obstacle to air navigation
• Required proximity of land uses within the airport boundary
• Surrounding land uses
• Timing and scale of phased development of the airport
• Meteorology
• Size and scale of airport facilities being planned

Principle facilities to be considered in an airport plan are:

• Runways
• Taxiways
• Passenger terminal and aprons
• Cargo terminal and apron
• Rescue and firefighting services
• Air traffic control tower
• Aircraft maintenance
• Long-term and short-term parking
• Access roads
• Public transport access
• Airport maintenance and engineering base
• Navaids
• Lighting
• Flight kitchens
• Fuel farm
• General aviation terminal and apron
• Sewage treatment and pumping station
• Electric sub-station
• Security fence and control gates
• Hotels
• Industrial uses

# Runway Orientation

Because of obvious advantages of landing and taking off into the wind, runways are oriented in the direction of prevailing wind.

Aircraft may not maneuver safely on a runway when wind contains large component at right angle to the direction of travel.

The point at which this component (cross wind component) becomes excessive will depend upon the size and operating characteristics of the aircraft.

Factors affecting the determination of the siting, orientation and number of runways:

• weather, in particular the runway/aerodrome usability factor, as determined by wind distribution, and the occurrence of localized fogs;
• topography of the aerodrome site and its surroundings;
• type and amount of air traffic to be served, including air traffic control aspects;
• aeroplane performance considerations; and
• environmental considerations, particularly noise.

➼ Head wind

direction of wind opposite to the direction of landing and takeoff

• Takeoff: head wind provides greater lift on the wings, thus shorter length of runway is enough
• Landing: Headway provides a braking effect and aircraft comes to stop in a smaller length of runway.

If landing and takeoff are done along the wind direction, it may require longer runway length.

➼ Cross wind Component

it is not always possible to obtain the direction of wind along the direction of the center line of runway, this Normal wind component is called cross wind component. And it may interrupt the safe landing and takeoff of the aircraft. VSinθ is the Cross wind Component.

➼ Wind Coverage

The percentage of time in a year during which the CWC remains within the limit is called Wind Coverage.

• FAA standards for mixed air traffic wind coverage should be 95 % with the limit of 25 kmph. CWC.
• For busy airport, WC may be 98 -100 %

➼ Wind Rose method

Typically wind rose is applied for the orientation of runway.

a. Wind Rose type I: It is the graphical representation of wind data, direction and intensity. Data should be collected for the period of 5 to 10 years. Wind data average of 8 years period. Total % = 86.5. (100 – 86.5 ) = 13.5 % of time wind intensity is less than 6.4 kmph. This period is called Calm Period.

b. Wind Rose type II: In this method a transparent template is prepared for determining the runway orientation. The wind data shown in the table are plotted on a wind rose by replacing the percentage in the appropriate segment of graph. On the wind rose, the circles represent wind velocity in miles per hour and the radial lines indicate wind direction.

# Air traffic management (ATM)

The general objective of ATM is to enable aircraft operators to meet their planned times of departure and arrival and adhere to their preferred flight profiles with minimum constraints and without compromising agreed levels of safety.

Objectives of air traffic services

• Prevent collision between aircraft;
• Prevent collision between aircraft on the maneuvering area and obstructions on that area;
• Expedite and maintain an orderly flow of air traffic;
• Provide advice and information useful for the safe and efficient conduct of flights;
• Notify appropriate organizations regarding aircrafts in need of search and rescue aid and assist such organization as required.
• The air traffic services shall comprise three services

➼ Communication:- is the exchange of voice and data information between the aircraft and air traffic controllers or flight information centers.

➼ Navigation:- Navigation pinpoints the location of aircraft for the crew.

➼ Surveillance:-  Surveillance pinpoints the location of the aircraft for Traffic Controller. It includes the communication of navigation information form Aircraft to Air traffic controllers, which facilitates the continuous mapping of the relative position of Aircraft.

Air Transport in Nepal 1.       1949: The date heralded the formal beginning of aviation in Nepal with the landing of a 4 seater lone powered vintage Beach-craft Bonanza aircraft of Indian Ambassador Mr. Sarjit Singh Mahathia at Gauchar. 2.       1950: The first charter flight By Himalayan Aviation Dakota from Gauchar to Kolkata. 3.       1955: King Mahendra inaugurated Gauchar Airport and renamed it as Tribhuvan Airport. 4.       1957: Grassy runway transformed into a concrete one. 5.       1957: Department of Civil Aviation founded. 6.       1958: Royal Nepal Airlines started scheduled services domestically and externally. 7.       1959: RNAC fully owned by HMG/N as a public undertaking. 8.       1959: Civil Aviation Act 2015 BS. promulgated. 9.       1960: Nepal attained ICAO membership. 10.   1964: Tribhuvan Airport renamed as Tribhuvan International Airport. 11.   1967: The 3750 feet long runway extended to 6600 feet. 12.   1967: Landing of a German Airlines Lufthansa Boeing 707. 13.   1968: Thai International starts its scheduled jet air services. 14.   1972: Nepalese jet aircraft Boeing 727/100 makes a debut landing at TIA. ATC services taken over by Nepalese personnel from Indian technicians. 15.   1975: TIA runway extended to 10000 feet from the previous 6600 feet. 16.   1976: FIC (Flight Information Center) established. 17.   1977: Nepal imprinted in the World Aeronautical Chart. 18.   1989: Completion of International Terminal Building and first landing of Concorde. 19.   1990: New International Terminal Building of TIA inaugurated by King Birendra. 20.   1992: Adoption of Liberal Aviation Policy and emergence of private sector in domestic air transport. 21.   1993: National Civil Aviation Policy promulgated. 22.   1995: Domestic Terminal Building at TIA and Apron Expanded. 23.   1998: CAAN established as an autonomous Authority. 24.   2002: Expansion of the International Terminal Building at TIA and the construction of a new air cargo complex. 25.   2003: Rara airport (Mugu), Kangeldanda airport (Solukhumbu) and Thamkharka airport (Khotang) brought in operation. 26.   2004: Domestic              operation  by      jet         aircraft commenced. 27.   2005: International flights by two private operators began. 28.   2006: A new comprehensive Aviation Policy introduced. GMG Airlines of Bangladesh, Korean Air and Air Arabia started air service to Nepal.

# Tribhuwan International Airport

The Tribhuvan International Airport (TIA), situated 5.56 km east of Kathmandu city is in the heart of the Kathmandu Valley

Coordinates: 274150N – 0852128E Elevation: 4390 ft.AMSL Reference Temperature: 27.8 C Runway Designation: 02/20 Runway Dimension: 10000 ft. x 150 ft. Runway Surface Strength: 54 F/A/W/T Apron Capacity – Int’l: 9 Medium and Wide Body Category Aircraft Domestic: 17 Small Aircraft Helipad: 13 Helicopters Fire Fighting Category: Cat IX Service: Air Traffic Control Service (aerodrome Control, Approach Control and Area Control) Aeronautical communication Service Aeronautical Information Service more detailing please visit TIA site

Note: Most Dangereous airport in word is Tenzing-Hilary Airport, lies in Lukla, Nepal

Multiple Choice Question ➼ Airport Engineering

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