Runway – is an area on a land prepared for the purpose of Take off and Landing of the aircraft.
Stopway – is a rectangular area of same width as Runway, which starts at the end of the runway, onto which an a/c can be stopped in the event of an abandoned Take off.
TORA – Take off Run Available, it is the physical length of the runway available for Take off purpose.
ASDA – Accelerate Stop Distance Available, it is the physical length of the Runway and Stopway available to be used in the even of a rejected Take off.
TODA – Take off Distance Available, it is the length of the TORA + Clearway for obstacle clearance.
Threshold – is the beginning portion of the Runway usable for landing and Take off.
Displaced Threshold – Sometimes a Threshold is displaced, from its previous position; it is generally done due to the rising terrain on the approach path of the Runway to provide obstacle clearance. The Runway length given on the Jepessen Airport charts includes the entire length of the runway, including the Displaced Threshold, since the same can be used for lining up the a/c for take off on the Runway. It is a good practice to use the Displaced Threshold for lining up onto the runway, and use the optimum length of the runway available for Take off.
Clearway
Clearway – is a rectangular area, which can be over ground or over water, which starts at the end of the runway, over which an a/c can make initial climb to reach Screen height.
It has a maximum length which cannot be more than half the length of the Runway.
It has a width of not less than 75 Meters either side of the extended Runway centerline.
It should provide obstacle clearance of a plane sloping upwards at 1.25° from the end of the Runway.
Clearway must provide a obstacle clearance of 1.25° from the end of the Runway
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Obstacle Clearance Plane
Obstacle Clearance Plane – is a requirement for aerodrome operations, it must provide an obstacle clearance plane of 1.2° from each end of the Runway. There should be no obstacles from either side of the beginning of the Runway centerline to 200 feet either side, and then increasing to 500 feet either side of the runway centerline at the end of the Runway till 1500 feet length from the Runway. After which it remains at 500 feet either side of the Runway centerline.
