TRANSPORTATION ENGINEERING - II - AIRPORT ENGINEERING

TRANSPORTATION ENGINEERING - II - AIRPORT ENGINEERING:
FACTORS AFFECTING SELECTION OF SITE FOR AIRPORT, AIRCRAFT CHARACTERISTICS, ZONING LAWS, RUNWAY LENGTH, CORRECTION FOR RUNWAY LENGTH, ORIENTATION OF NRUNWAY, WIND ROSE DIAGRAM, RUNWAY LIGHTING SYSTEM.

1. AIRPORT ENGINEERING Govinda Rajulu Badana UNIT - IV

2. Introdu c tion 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

3. Air T ransportation 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

4. Air T ransportation 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

5. 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 Pequet) crossing Ganga 1912 – Flight between Delhi and Karachi 1914 – Air passenger transport began in Germany

6. 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

7. 1928 – Havana Convention on civil aviation 1929 – Warsaw convention on civil aviation 1944 – international civil aviation convention 1944 – Chicago convention, establishing provisional ICAO (international civil aviation organization) 1945 – International Air Transport Association (IATA) established in meeting at Havana, Cuba 1947 – ICAO was established as a body of United Nations

8. 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)

9. 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

10. 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.

11. 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).

12. 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

13. 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)

14. Airport planning requires more intensive study and forethought as compared to planning of other modes of transport. This is because aviation is the most dynamic industry and its forecast is quite complex. Unlike rail, road and water transportation, air transportation has yet not reached a steady state in design. It is very difficult to predict for the airport, satisfying the present needs, whether this airport shall prove adequate for the new types of aircrafts which may emerge after 10 years. The airport design engineer, therefore is required to keep in touch with the recent trends and also with likely future projections in the aviation activities. AIRPORT PLANNING & DESIGN

15. AIRPORT MASTER PLAN Air port master plan refers the planner’s idealized concept of the form and structure of the ultimate development of the airport This plan is not simply the physical from of ultimate development but a description of the staging and both the financial implications and the fiscal strategies involved. Master planning can apply to the construction of new airports as well as to significant expansion of existing facilities.

16. The objectives of the master plan according to FAA(Federation Aviation Agency) are: To provide an effective graphical presentation of the ultimate development of the airport and of the anticipated land uses adjacent to the airport. To establish a schedule of priorities and phasing for the various improvements proposed in the plan. To present the pertinent back-up information and data which were essential to the development of the master plan. To describe the various concepts and alternatives which were considered in the establishment of the proposed plan. AIRPORT MASTER PLAN

17. FAA (Federation Aviation Agency) Recommendations The structure of the airport master plan procedure recommended by the FAA consists of four separate phases. Phase I : Airport Requirements The first phase essentially is an examination of the scale and timing of new facilities with respect to the anticipated demand and the status of existing facilities in the context of anticipated environmental implications. Phase II : Site selection Evaluation of the available sites should include study of airspace requirements, environmental impact, development, access availability of utilities ,land costs and availability, site development costs and political implications.

18. Phase III : Airport Plans The proposed facility is then represented precisely with respect to the following points: (i) Airport layout plan: Indicates the configuration location and size of all physical facilities. (ii) Land Use Plan: Details of land use within the proposed airport boundary and the land use of areas. (iii) Terminal Area Plans : Show the size and location of the various buildings and activity areas within the terminal area complex. (iv) Airport Access Plans : Show proposed routings for the various access modes to the transportation information of the region. FAA (Federation Aviation Agency) Recommendations

19. Phase IV : The Financial Plan Collection of data in the four principal areas of financial importance : (i) Schedules of Proposed Development. (ii) Estimates of Development costs. (iii) Economic Feasibility Analysis. (iv) Financial Feasibility Analysis. Site Selection for Airport 1.The selection of suitable site for an airport depend on the class of airport under consideration. 2. The factors listed below are for the selection of suitable site for a major airport installation. FAA (Federation Aviation Agency) Recommendations

20. (1) Regional plan. (2) Airport use. (3) Proximity to other airports. (4)Ground accessibility. (5)Topography. (6)Obstruction. (7) Visibility. (8) Wind. (9) Noise nuisance. (10) Grading& Drainage and Soil characteristics. (11) Future development. (12) Availability of utilities from town. (13) Economic consideration.

21. Regional Plan : Site selected should fit well into the regional plan here by forming it an integrated part of national networks of airport. Airport Use: Selection of site depends upon use of airport whether for civilian purpose or for military operations. Site should be such that it provide natural protection to the area from air raids. Proximity to other airports: The site should be selected at a considerable distance from the existing airports. So that the aircraft landing in one airport not interfere with the movement of aircraft at the airport. The following minimum spacings have been suggested as a guide for planning:

22. For airports serving small general aviation aircrafts under VFR(Visual Flight Rules) conditions =3.2 km.(2miles. For airports serving bigger aircrafts, say two position engine, under VFR conditions =6.4 km.(4 miles). Ground Accessibility: The site should be so selected that it is readily accessible to the users. Minimum time required to reach an airport should be 30 minutes and best location is a site adjacent to the main highway. Topography: The Includes natural features like ground contours, trees, streams etc; A raised ground is considered to be an ideal site for an airport because

23. less obstruction in approach zones and turning zones. Natural drainage, low and may result in flooding. More uniform wind. Better visibility due to less fog. Obstructions: When aircraft is landing or taking off, it loses or gains altitude very slowly as compared to the forward speed. Hence for this reason, long clearance areas are provided on either side of the runway known as approach areas. These areas should be kept free of obstructions. Visibility: Poor visibility lowers the traffic capacity of the airport. The site selected should be free from visibility reducing conditions like smoke, fog etc.,

24. Wind: Runway is so oriented that landing and take off is done by heading into the wind data which is direction, duration and intensity of wind should be collected over a minimum period of 5yrs.This helps in proper orientation of the runway and influence the shape of the needed for the development of airport. Noise nuisance : Site should be so selected that landing and take off parts of the aircrafts pass ones the land which is free from residential or industrial development. Grading & Drainage: Play an important role in the construction and maintenance of airport which on turn influences the site selection.

25. Future Development : Considering that the air traffic volume will continue to increase in future more numbers of runways may have to be provided for the increased traffic. Availability of utilities from town: An airport how to be provided with facilities like water supply, telephone, electricity etc., Economic consideration : Cost estimates for site selection should include land cost, cleaning & grading of land, drainage, removal of hogards, lighting, coust of buildings, acess roads and automobile areas. Amongst the various alternative sites, one which is economical should be preferred.

26. Aircraft components Reference: http://www.grc.nasa.gov/WWW/k-12/airplane/airplane.html

27. Aircraft components

28. Aircraft components

29. Aircraft components

30. AEROPLANE COMPONENTS PARTS

31. Aircraft characteristics Engine Type and Propulsion Atmospheric propulsion and trans-atmospheric propulsion Propulsion may be through any type of engine Piston engine, jet engine (turbo jet, turbo propulsion or ram jet) or rocket engine etc. Piston – most conventional form, fuel is converted to mechanical or electrical energy Jet – these have a capacity to provide a jet with a height thrust, which is used for movement. Different types of jet engines exist. In case of turbo, jet known as turbo propulsion is used. Here not simple thrust is used, instead huge amount of air is sucked, and is transformed into jet. Rocket engines used in trans-atmospheric propulsion systems Speed, power increases from piston to rockets

32. Type of propulsion Engine Speed limit kmph Piston 250 to 750 Ram jet 1280 to 2400 Rocket 4600

33. Operative altitude of aircraft depends up on Type of engine Propulsive power available to aircraft Piston engines – low altitudes Turbo jet or turbo propulsions – low to high altitudes Ram jets – used in missiles at middle altitudes Where other type of movements are less Rocket jets – outside atmosphere

34. Size of air craft: One of the important aspect Here not just the size of main body, but the size of overall wing space is considered important By ICAO, FAA guidelines, air craft wing space is considered but not main body for classifying the airport. It is important to look at different aspects of size.

35. Size of Aircraft Size of Aircraft involves Fuselage length From nose of the aircraft to the tail of the aircraft Fuselage is the area which compasses the fuel which is to be transported along the aircraft, which is used along the path, at the same time it also encompasses the payload and that is the passengers and the freight that will also be placed within the fuselage length. Height and width (at tail) Since additional wings are provided at tail in lateral, vertical directions Gear tread (distance between main gears) Wheel base Distance between nose gear (pilots location) and main gear(at wings connection)

36. Wing span Measured at the location of wings to the furthest ends of wings Wing span decides Width of taxi way Clearance between two parallel traffic ways Size of apron and hanger Width of hanger gate

37. Aircraft characteristics Length of aircraft decides Widening of taxi way on curves Sizes of apron and hanger Height of aircraft or empennage height It decides the height of hanger gate The gear tread and wheel base Min turning radius of the aircraft.

38. Aircraft characteristics – weight & wheel configuration Pavement thickness, design, materials etc., depend on the weight and wheel distribution of aircraft. Different types of weights Maximum gross take-off weight Total amount of weight when it is taking off from runway Maximum standard landing weight Fuel consumed during transport will be deducted from take-off weight Operating empty weight Operating at zero pay load

39. Weight and wheel distribution Pay load Load for which revenues are generated (passengers + freight) Zero-fuel weight Air craft reaching destination and fuel is getting empty Note: (maximum is taken considering biggest aircraft allowed at airport

40. Wheel configuration defines how the weight will be transferred to the bottom More the no of wheels, lesser the stress, hence less thickness enough. Different wheel combinations available based on size of aircraft. Single tandem, duel tandem and multi axle tandems are used based on the size and weight of air craft. Some wheel configurations are shown in the next slide.

41. Minimum turning radius While making a turn, the nose gear is steered and hence it makes an angle with the axis of main gear called angle of rotation. The point of intersection of axis of main gear and line through axis of steered nose gear is called point of rotation. Max angle varies between 50 to 60 degrees The line joining the centre of rotation and the tip of farthest wing of aircraft is known as minimum turning radius. The amount depends on size of aircraft

42. Minimum circling radius Related to movement of aircraft with in the air Radius in space required for the aircraft to take a smooth turn It depends on Type of aircraft (size, power propulsion system etc.,) Air traffic volume Weather condition It is the total radius which is provided at the top of the air port in which the aircraft will be circling if it is not allowed to land.

43. Speed Air speed Speed of air craft in air relative to medium. Indicated speed Indicated by the instrument onboard 2% lower than actual true speed The reason is it is relative speed what is true, to get the correct value of speed 2% is reduced for resistance in air.

44. Capacity of air craft No of passengers and amount of cargo it can handle Dependant on Size Propulsive power of aircraft Speed of air craft

45. Noi s e Big problem if nearer to developed areas Major sources of noises are Engine Machinery (more during landing) Primary jet (more during take-off) Disturbances are more during take off Since the inception of jet engines the noise has been reduced to a great extent

46. Vortices at tail end Vortices form at tail when moving at high speed Have a tendency to break tail if they are heavy and eddies are formed Vortices are made of 2 counter rotating cylindrical masses of air extending along the path These are formed near tail ends of wings or tail end of aircraft The velocity of wind in these vortices will be very high

47. Jet blast This aspect belongs to aircrafts having jet engines This is the blast that comes out of jet engine at the rear of air craft to provide a force for movement If we consider the case where air craft is standing and jet blast is coming from back side, it is so hot and creates severe conditions The severity depends on Height of tail pipe Angle of tail pipe Hence, blast fences are needed to control the damage to the pavements

48. Fuel spillage Spilling of fuel occurs when the engine is shutdown or loosing speed It is spilled fuel from the engine or other locations into the aircraft. This may cost the speed when it is moving on runways or taxiways or apron.

49. Influencing characteristics of aircraft on design of airport Engine type and propulsion Size Aircraft weight and wheel configuration Minimum turning radius Minimum circling radius speed capacity Noise Vortices at tail ends Jet blast Fuel spillage

50. Engine type and propulsion decides Size of the aircraft Speed length of the runway (more speed ->longer runway) Weight (more if bigger propulsion system) Carrying capacity (depends on size) Noise (depends on propulsion system) Circling radius (high power, and speed crafts have high radius) Range (distance it can move without refueling) Maintenance facilities Ballast pads (required for jet propulsion)

51. Size of aircraft influences Load carrying capacity Other facilities like apron, terminal area etc. Bigger the size larger are facilities to be provided at airport terminal building Wing span will increase with size It has effect on taxiway width Separation between traffic lanes Size of gate, apron size, width of hanger etc. Length Widening of taxiway on curves, apron, hangers, width of exit way Height : further influences height of hanger gate Wheel base, gear tread also changes

52. Aircraft wheel configuration Thickness of runway, taxiway, apron Distribution of load to ground Turning (difficult for more weight in case of sharp curves) Stability (depends on the support system provided and also depends on wheel configuration)

53. Minimum turning radius Radius of taxiways Taxiway is the connecting pavement which is provided between the runways and aprons Minimum circling radius: Defines the minimum distance between 2 near by airports For larger aircrafts it will be in kms hence more distance is required between 2 airports Adjustments of timings of landing and takeoff Airport capacity(decrease with increased air circle time) Zoning laws related to height of obstruction

54. Speed Reduces journey time Increase in frequency of operations Improving and broadening the air network system Capacity Processing terminals Passenger and baggage handling facilities Cargo processing Size of apron, special equipments etc.

55. Vortices at tail ends Hazardous to aircraft Stresses at fuselage and other joints Pressure under wings producing lifts and drags Jet blast Inconvenience to passengers May do harm to airport runways and other components of airport Fuel slippage Badly effects bitumen pavements Causes slip of wheels

56. 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

57. Development of surrounding area Ground accessibility Presence of other airports Regional plan Soil characteristics Surrounding obstructions Use of air port

58. 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

59. 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.

60. 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

61. Economy of construction Alternate sites to be examined Availability of local construction material Terrain even or not Problematic areas Water logging areas Reclaimed areas

62. 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

63. 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

64. 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

65. 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

66. Factors affecting the size of airport Size of airport Defined by the space for operators, controlling systems, facilities, manpower etc. Controlled by peak aircraft traffic, aircraft characteristics Elevation of airport size above MSL density and air pressure reduces Effects runway requirements, lift, drag etc. Aircraft performance varies altitude, air density, pressure , temperature Meteorological conditions Wind, temperature Effects runway orientation, length and no of runways reqd. Performance characteristics of aircraft Volume of air traffic (peak hour volume, size of aircraft, nature of air traffic, runways, taxiways etc.,)

67. 1. The airport obstruction is that which causes obstruction during the landing and take off operations of an aircraft and also in the approach and turning areas. 2. At the time of site selection itself, steps should be taken to curb the possibility of developing any future obstruction. 3. Hence Zoning ordinances regarding the permissible height of structures and land use with in the airport boundary need implementation as soon as the site is selected. Classification of obstructions : obstructions for safe navigation are broadly divided into 2 categories. 1.Objects protruding above certain imaginary surfaces. 2. Objects exceeding their limiting heights above the ground surface in approach zones and turning zones. AIRPORT OBSTRUCTIONS(Zoning Laws) :

68. Runway : A long and comparatively narrow strip which is paved except for small aerodromes. Aerodrome : A defined area of land or water which is intended to be used for the arrival, departure and movements of aircrafts. Runway Capacity : It is defined as the ability of a runway system to accommodate aircraft landings and take-offs. It is expressed in operations per hour or operations per year. Apron : A defined area which is used to accommodate aircrafts for loading and unloading of passengers and cargo, parking, refueling etc., Imaginary Surfaces : The types of Imaginary Surfaces are : (i) Take-off climb surface (ii) Approach surface (iii) Inner horizontal surface (iv) Conical surface (v) Transitional surface (vi) Outer horizontal surface

69. (i) Take-off climb surface : The take off climb area shall be established beyond the end of the runway or clear way for each runway direction intended to be used for takeoff aeroplanes. (ii) Approach surface : The approach surface shall be established from the smaller ends of the runway strip for each runway direction intended to be used for the landing of aeroplanes. (iii) Inner horizontal surface : It is the surface located in a horizontal plane above an aerodrome and its surrounding. The shape of the IHS need not necessarily be circular. The radius or outer limits of IHS shall be measured from airport reference point(ARP) or points established for such purposes. Where the runway length is 600m(2000 ft) or more less than 750 m(2500 ft), the IHS shall be a circular surface with radius of 4000 m(1300 ft) from ARP.

70. (iv) Conical surface : It extends upwards and outwards from the periphery of the inner horizontal surface. The limits of conical surface comprises of A lower edge coincident with periphery of inner horizontal surface. (v) Transitional surface : It is a complex surface along the side of the strip and part of the side of approach surface that slopes upwards and outwards to the inner horizontal surface. This is intended to serve as the controlling obstacle limitation surface for buildings etc (vi ) Outer horizontal surface : It is not proposed to establish OHS for aerodrome with runways of length less than 900 m. It is circular in plane with centre located at ARP. The height of OHS is 150m above the ARP elevation. The constructions providing above this surface shall not be permitted.

71. 1.Runway is usually oriented in the direction of prevailing winds. 2. The head of wind i.e. the direction of wind opposite to the direction of landing and takeoff, provide greater lift on the wings of the aircraft when it is taking off. Cross wind component : 1.The normal component of wind is called cross wind component. 2.This may interrupt the safe landing and takeoff of aircraft. FAA The max permissible cross wind depends upon size of aircraft and wing configuration. Federal aviation agency recommends CW component Small aircrafts >| 15kmph Mixed traffic >| 25kmph Airports serving bigger aircrafts –ICAO (International civil aviation organization) recommends cross wind component should not exceed 35kmph. RUN WAY DESIGN Run Way Orientation:

72. Wind coverage : The percentage of time in a year during which the cross wind component remains within the limits as specified above is called wind coverage. According to “FAA” runways handling mixed air traffic should be so planned that 95% of time in a year, the cross wind component does not exceed 25 kmph . For busy airports the wind coverage may be increased to as much as 98% to 100% .

73. Wind Rose : The wind data i.e. direction, duration and intensity are graphically represented by a diagram called wind rose. The wind data should be collected for a period of at least 5years preferably 10 years. Wind rose diagrams can be plotted in 2 ways Type -I – Showing direction and duration of wind. Type –II –Showing direction, durations intensity of wind.

74. Type-I wind rose : The radial lines indicate wind direction and each circle represents the duration of wind. In the given tabular from table 6.1 it is observed that the total % time in a year during which the wind blows from north direction is 10.3%. This value is plotted along north direction in the figure similarly all other values are also plotted along their respective direction. The best direction of runway is usually along the direction the longest line on the wind rose diagrams. From the fig. the best direction orientation of runway is along the north-south direction . . If deviation of wind direction up to (22.5 +11.25 )from the direction of landing and takeoff is permissible, the % of time in a year during which the runway can safely be used for landing and take off will be obtained by summing the percentages of time along NNW,N,NNE,SSE,S and SSW directions .

75. Type-II wind rose : 1.Draw three equi -spaced parallel lines on a transparent strip in such a way that distance between the two near by parallel lines is equal to the permissible cross wind component. 2. Place the transparent paper strip over the wind rose diagram in such a way that the line passes through the centre of the diagram. 3. With the centre if wind rose, rotate the tracing paper and place it in such a position that the sum of all the values indicating the duration of wind, within the two outer parallel lines, is the maximum .

76. The geometric standards of an airport depend upon the performance characteristics of the aircrafts that will use the airport, the weather conditions and the services rendered by the airport ,i.e., weather international or for domestic use. The airport classification helps in the design of airport and to establish the uniformity in the design standards. It also assists the pilots in identifying the size and the services which the airport can provide. The airports have been classified by various agencies viz. International Civil Aviation Organisation (ICAO),Federal Aviation Agency(FAA),United States Air force etc. AIRPORT CLASSIFICATION

77. International Civil Aviation Organisation (ICAO) classification : The ICAO classifies the airports in two ways. In the first method, the classification is based on the basic runway length of the airport . It also describes various other geometric standards of the airport . 4 . The classification has been done by using code letters viz. 5. A to E in which the A type of airport has the longest runway length and E type has the shortest length. 6. In the second method classification is based on the equivalent single wheel load (ESWL) and the tire pressure of the aircraft which will use the airport.

78. ICAO gives various geometric standards for the airport design. The following items are considered in the geometric design of runways : (i) Runway length (ii) Runway width (iii) Width and length of safety area (iv) Transverse gradient (v) Longitudinal and effective gradient (vi) Rate of change of longitudinal gradient (vii) Sight distance RUNWAY GEOMETRIC DESIGN

79. Runway Length : To obtain the actual length of runway, corrections for elevation, temperature and gradient. Runway Width : ICAO recommends the pavement width varying from 45m (150 ft ) to 18m (60 ft ) for different types of airports . Width and Length of safety area : Safety area consists of the runway, which is a paved area plus the shoulder on either side of runway plus the area that is cleared, graded and drained . Transverse Gradient : Transverse gradient is essential for quick drainage of surface water . If surface water is allowed to pond on the runway, the aircraft can meet severe hazards.

80. Longitudinal and effective gradien t : ICAO gives the following recommendations for the maximum longitudinal gradient and the maximum effective gradient . For Longitudinal gradient : A, B and C types of airports = 1.50 percent (%) D and E types of airports = 2.00 percent (%) For effective gradient : A, B and C types of airports = 1.00 percent (%) D and E types of airports = 2.00 percent (%)

81. RUN WAY LENGTH ICAO Airport Classification Airp o rt Type Basic Runway Length (m) Width of Runway P a v e m e n t (m) Max L o n gitu d i n al Grade (%) Max Min A >2100 2100 45 1.5 B 2099 1500 45 1.5 C 1499 900 30 1.5 D 899 750 22.5 2.0 E 749 600 18 2.0 Code No Equivalent Single Wheel Load (kg) Tire Pressure (kg/cm 2 ) 1 45000 8.5 2 34000 7.0 3 27000 7.0 4 20000 7.0 5 13000 6.0 6 7000 5.0 7 2000 2.5 Example: An airport B-3 would have basic runway length ranging between 1500-2099m. Single wheel load capacity of 27000 with a tire pressure of 7 kg/cm 2

82. RUNWAYS Definition It is a strip of land used by aircrafts for take-off and landing operations. It is perhaps the single most important facility on the airport .

83. Actual Runway Length = Basic Runway Length + Corrections

84. Basic Runway Length (ICAO) Airp o rt Type Basic Runway Length (m) Width of Runway P a v e m e n t Max Longitudinal Grade (%) Max Min A >2100 2100 45 1.5 B 2099 1500 45 1.5 C 1499 900 30 1.5 D 899 750 22.5 2.0 E 749 600 18 2.0

85. Standard Atmospheric Parameters: Temperature at MSL = 15  C Pressure at MSL – 760mm of Hg Air Density = 1.225kg/m 3 If the standard atmospheric conditions vary due to any reason - corrections are applied to the basic runway length to calculate the actual runway length.

86. Corrections to basic R unway L ength There are three main corrections to be applied to basic runway length to determine the actual length of runway for an airport. These are: Elevation Correction Temperature Correction Gradient Correction

87. Elevation Correction Change in elevation affects air density, atmospheric pressure and temperature. Correction should be applied for change in altitude. The Elevation Correction is as shown below: Correction for Altitude: Increase runway length by 7 % per 300m altitude above MSL

88. Temperature Correction If standard temperature varies, correction to runway length should be applied: Compute Airport Reference Temperature (ART) Compute Standard Temperature at the given Elevation (STE) Compute Increase in ART above STE= ART- STE Apply Correction based on the value obtained in Step-3

89. Airport Reference Temperature (ART) ART = 𝑇 1 + 1/3(𝑇 2 − 𝑇 1 ) Where, 𝑇 1 = Monthly mean of average daily temperature for the hottest month of the year ( ° C ) 𝑇 2 = Monthly mean of maximum daily temperature for the same month ( ° C )

90. Standard Temperature at Elevation (STE) STE = Temperature at MSL +/- ( R ate of change of temperature x elevation) Rate of change of temperature with height is given as : 6.5°C / Km height ----------- Up to 11 Km height from MSL Constant at – 56.5°C ------- 11 – 20 Km height ( Stratosphere ) + 1°C / Km height -------------- 20 – 32 Km height ( Troposphere )

91. Temperature Correction Increase basic runway length by 1% for every 1 ° C rise in A irport Reference Temperature (ART).

92. Gradient Correction Longitudinal Gradient : If the gradient is steep, it may cause pre-mature lift- off or may cause structural damage It will consume more energy and will need longer runway to attain desired ground speed Effective Longitudinal Gradient : It refers of the average gradient computed by subtracting maximum and minimum elevations along the runway divided by the total length of runway.

93. Gradient Correction Runway length is increased at a rate of 20% for every 1% of the effective gradient Note: This correction is applied only if the combined correction for Elevation and Temperature remains less than 35%

94. Summary: Basic Runway Length Corrections Correction Amount Combined Corrections 1 Elevation Correction 7% per 300m rise above MSL Th e c o mbined correction for Elevation and T emp e r a tu r e should NOT exceed 35% 2 Temperature Correction 1% for every 1  C rise in airport reference temperature. 3 Gradient Correction 20% for every 1% of the effective gradient Th e c o mbined correction for Elevation and T emp e r a tu r e should less than 35%

95. Example - 1: Compute the airport reference temperature if the monthly mean of average daily temperature of the hottest month is 27.3°C and monthly mean of maximum daily temperature for the same month is 43.2°C. Solution : Airport reference temperature (ART) = 𝑇 1 + (𝑇 2 − 𝑇 1 ) Where, 𝑇 1 = Monthly mean of average daily temperature of the hottest month (°C ) 𝑇 2 = Monthly mean of maximum daily temperature of the hottest month (°C).   ART = 27.3 + 1/3 (43.2 − 27.3) = 27.3 + 5.3, ART = 32.6°𝐶

96. Problem 2 : If the airport is located at mean sea level (MSL), and the airport reference temperature is that calculated in Problem 1. Apply temperature correction to the runway length. Solution Given: Airport Reference Temperature : 32.6 ° C . At MSL, the Standard Temperature at Elevation (STE) is given as 15 ° C . The difference in temperature = (ART-STE) = 32.6-15 = 17.6 ° C Let the runway length be L meters. The temperature correction is applied to increase the runway length, L, by 1% for every degree rise in temperature. Hence , The correction is : L x 17.6°C = 0.176 L The Corrected length = L + 0.176L = 1.176 L  

97. Basic Runway Length It refers to the length of an airport runway under the following assumptions: Related to runway: No wind is blowing on runway Runway is levelled (No effective gradient) Related to Airport: Airport is at sea level The temperature at the airport is 15 ° C (Standard Temperature) Related to aircraft: Aircraft is loaded to its capacity Related to route to destination: No wind is blowing on the way to destination Standard temperature prevails along the way

98. Factors Affecting Basic Runway Length The following factors affect the calculation of basic runway length: Aircraft characteristics Airport environmental conditions Safety requirements

99. Aircraft Characteristics Power and propulsion system Critical aircraft: The aircraft that requires longest runway length for landing and take-off operations. The length of runways for both the operations may be determined from the flight manual of aircraft performance. Gross landing and take-off weight of the aircraft Aerodynamic and mechanical characteristics

100. Airport Environment Atmosphere Temperature Surface wind Altitude Runway Gradient

101. Safety R equirements Normal landing case Normal take-off case Engine Failure Case

102. Normal Landing Case The aircraft should come to a halt within 60% of the landing distance. The runway of full strength pavement is provided for the entire landing distance

103. Normal Landing Calculations Field Length (FL) = landing distance (LD) LD = Stopping distance (SD) / 0.60 = SD x 1.67 Length of full strength runway = LD

104. Normal Take-off Case The take-off distance (TOD) must be equal to 115% of the actual distance the aircraft uses to reach a height of 10.5m TOD should be equal to 115% of the distance to reach a height of 10.5m.

105. Normal Take-off Calculations Field Length (FL) = Full Strength (FS) runway + Clearway (CW) TOD = 1.15 x D 10.5m CW = 0.5[TOD -1.15(LOD)] Take-off Run (TOR) = TOD – CW Length of full strength runway (FS) = TOR

106. Normal Take-off Case So the runway should look as shown in Figure

107. Normal Take-off Runway Composition It requires a clearway, as shown in figure below. The width of clearway should not be less than 150m (500ft) The clearway ground area should not have any object protruding a plane inclined upwards at a slope of 1.25% from the end of runway.

108. Engine Failure Case-Criterion It is an emergency condition! This condition applies when the aircraft is speeding up on the runway to take- off and pilots detect some problem in the engine(s): Two Options exist: Option 1. To abort the flight (This is permissible only if the speed of aircraft is below the designated speed (engine failure speed), or Option 2. Proceed with the take-off and turn the aircraft back from the turning zone (This option applies if speed is > engine failure speed). Option -1 is important from runway length design perspective: The runway should be adequately long to let the plane to de-accelerate and come to a safe halt without running beyond the runway.

109. Stopping in Emergency: Calculations-1 Engine Failure, take-off proceeded case Field Length (FL) = FS + CW TOD = D 10.5 CW = 0.5[TOD-LOD] TOR = TOD + CW Length of FS runway = TOR

110. Stopping in Emergency: Calculations-2 Engine Failure, take-off aborted case FL = FS + SW FL = Deaccelerate stop distance (DAS)

111. The Required Basic Runway length Field Distance = max{TOD 2 , TOD 3 , DAS, LD} Full Strength Runway (FS) = max{TOR 2 , TOR 3 , LD} SW = DAS – max{ TOR 2 , TOR 3 , LD} CW = min{(FL - DAS), CL 2 , CL 3 } SWmin = CWmin = CW max = 300m

112. AIRPORT LIGHTING

113. A line of lights on an airfield to guide aircraft in taking off or landing during night As a guide to pilot Emergency power supplies Different types of light flashing white or pulsating yellow to steady red and even blue

114. General Airport Lighting Approach lighting Taxiway lighting Runway Light i ng TYPES OF AIRPORT LIGHTING

115. 1.General Airport Lighting Includes Beacon Lights on top of tower, buildings The Airport Beacon : large, powerful rotating light highly visible from miles away Rotate green and white Steady red beacon on top of airport building to aid in collision avoidance for low-flying aircraft.

116. At airports Beacon: White and Green rotating light At Heliports Beacon: White and Yellow rotating ligh t

117. 2. Taxiway Lighting Taxiway Edge Lights: Blue, Lines taxiway Taxiway Center Light: Green Light Clearance Bar Lights: Steady yellow, visibility of hold line Stop Bar Lights: Steady red, ATC in low visibility situation, across taxiway at hold short line Runway Guard Lights: A pair of two steady yellow light at hold short line, may be flashing

118. Taxiway centerline light Taxiway edge light Runway Guard light Steady Bar lights Clearance Bar lights

119. 3.Runway Lighting Runway End Identifier Lights: white flashing light one on each side of approach end of runway Runway Edge Light Systems (HIRL/MIRL/LIRL):steady white light on edges of runway Runway Centerline Lighting System (RCLS)

120. 3.Runw a y Lighting (Contd ..) Touchdown Zone Lights (TDZL) : Define landing portion of runway, Up to midpoint Land and Hold Short Lights (LAHSO) Runway status light or Runway entry light (REL)

121. Min of (2000 ft and half the runway)

122. TDZL RCLS 50 feet interval 100 feet

123. 4.Approach Lighting An approach lighting system or ALS , is a lighting system installed on the approach end of an airport runway Consisting of a series of light bars, strobe lights, or a combination of the two that extends outward from the runway end

124. 4.Approach Lighting contd .. Visual glide slope indicators Visual guide to pilot during descent to maintain stabilized approach This includes: VASIs, or Visual Approach Slope Indicators: lights indicating aircraft is too high or too low on approach PAPI, or Precision Approach Path Indicator

125. Visual Approach Slope Indicators ( VASI )

126. VASI contd..

127. Factors Affecting Airport Lighting Airport classification Availability of power Amount of traffic Nature of aircraft Type of night operation plan Type of landing surface provided Weather condition