Lafyar Cokov

12th Feb 2008, 23:44

Ok - I am now stumped - there is the following question in the Cathay Book:

On a 3° glide path, OAT -25°, OM crossing height of 1760', the aircraft altitude will indicate:

a. 1820'

b. 1760'

c. 1720'

The answer given is A. I agree that the answer must be higher than the indicated but using the standard (approximate) temp error calculation I reach:

(Assuming Gnd OAT = -21°C)

4 * (21+15) * 1.8 = 4 * 36 * 1.8 = 259.2ft

Therefore answer is about 2020ft

Am I massively wrong or is the question out???

Cheers

On a 3° glide path, OAT -25°, OM crossing height of 1760', the aircraft altitude will indicate:

a. 1820'

b. 1760'

c. 1720'

The answer given is A. I agree that the answer must be higher than the indicated but using the standard (approximate) temp error calculation I reach:

(Assuming Gnd OAT = -21°C)

4 * (21+15) * 1.8 = 4 * 36 * 1.8 = 259.2ft

Therefore answer is about 2020ft

Am I massively wrong or is the question out???

Cheers