PH = 3480 – [(1021-1013)x30]
= 3480-240
= 3240
ISA at 3240 = 15-(2x3.2)
= 15-6.4
= 8.6
ISA dev = 24-8.6
= 15.4
Density Alt increases approx. 1000ft for every 8C above ISA
Therefore Density Height of Echo = 3240+[(15.4/8)x1000]
= 3240+1925
= 5165, which is pretty close to ‘B’.