18) For determining the basic runway.length, the landing case requires that aircraft should come to a stop within p % of the landing distance. The value of p is

19) According to ICAO, all markings on the runways are

20) Runway threshold is indicated by a series of parallel lines starting from a distance of

21) The width and interval of transverse centre line bars along the extended centre line of runway, in approach lighting system are

22) In Intrumental landing system, the middle markers are located