Airport Planning & Taxiway Design

AIRPORT PLANNING AND DESIGN

TAXIWAY DESIGN TAXIWAY DESIGN

TAXIWAY: Taxiway provides access to the aircrafts from the runways to the loading apron or service hangar.

Taxiway

Runway

Taxiway

Runway and Taxiway

Factors controlling Taxiway Layout Arrangements : • Taxiways should be arranged that the aircrafts which have just landed & taxiing towards apron should not interfere with the aircrafts taxiing for take-off. Busy airports : • The taxiway should be located at various points along the runway so that the landing aircraft leaves the runway as early as possible. Such taxiways are called “exit taxiways”.

High turn of speed: • Exit taxiways should be designed for high turn off speeds of aircrafts so that runway occupancy time gets reduced. Route : • The route should be a shortest distance from the apron to the runway end. Crossing: • Intersection of taxiway & runway should be avoided.

GEOMETRIC DESIGN STANDARDS • • • • • • • •

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

Geometric Design Standards For Taxiway  Length – should be as short as practicable.  Width – lower than the runway width. This is because the aircraft run on the taxiway are not airborne and the speed of

the aircraft on taxiway is lower. Hence pilot can easily ma oeuvre the aircraft over a smaller width of taxiway.  Width of safety area – it includes width of taxiway pavement plus shoulder on either side. The width of the shoulder is 7.5m on each side and are paved with light strength material.

Turning radius  Whenever there is change in direction of a taxiway, a

horizontal curve is provided. The curve is so designed that the aircraft can negotiate it without significantly reducing the speed. Circular curve with larger radius is suitable for this purpose.  The radius is given by R = V2/127f  where; R is radius in m, V is speed in kmph and f is 0.13.  Subsonic jet transport – min. 120m.  Supersonic jet transport – min. 180m.

 According to Horonjeff the radius of the taxiway should be so provided that the distance of the oleo strut of the near by main

gear is not less than 6m from the pavement edge.  Horonjeff formula:R = (0.388W2) / (T/2 – S)  Where;→R is the radius of the taxiway in meter→W is the wheel base of aircraft in meter→ T is the Width of taxiway pavement in meter→S is the distance between midway point

of the main gears and the edge of the taxiway pavement in meter.

 If the existing airport has to be upgraded to accommodate supersonic transport, it may be feasible to widen the pavement rather than increasing the radius.  Widening is done by providing a compound curve of radii R1and R2. the value of R1and R2 is obtained using;

R2= R – ((0.388W2/ R) + S) If exp. ((0.388W2/ R) + S) < T/2, no widening is needed. If it is > T/2, the radius R1 is R1=(Dr2+(T/2)+0.3R- R22-RT/2(R- R2) where Dr = 3W-0.4R if Dr