Correct Answer - Option 2 : X = 7; Y = 300
Explanation:
Basic Runway length:
It is the length of runway under the following assumed conditions at the aircraft
(i) Airport altitude at sea level.
(ii) Temperature at the airport is standard (15° C)
(iii) Runway is leveled in the longitudinal direction.
(iv) No wind is blowing on runway.
(v) Aircraft is loaded to its full loading capacity.
(vi) There is no wind blowing enroute to the destination.
(vii) Enroute temperature is standard.
Correction for Elevation, Temperature and Gradient:
(i) Correction for Elevation: Basic runway length is increased at the rate of 7% per 300 m rise in elevation above the mean sea level.
(ii) Correction for Temperature:
Airport reference temperature = \({T_a} + \frac{{{T_m} - {T_a}}}{3}\)
Where, Ta = Monthly mean of average daily temperature
Tm = Monthly mean of the maximum daily temmperature for the same month of the year
Total correction for elevation plus temperature ⇒ 35% of basic runway length
(c) Correction for Gradient:
(i) Steeper gradient results in greater consumption of energy and as such longer length of runway is required to attain the desired ground speed.
(ii) After having been corrected for elevation and temperature should be further increased at the rate of 20% for every 1% of effective gradient.
