Question

1. what effect does high density altitude have on aircraft performance?

oa. it increases engine performance.
ob. it reduces climb performance.
oc. it increases takeoff performance.

Explanation:

High density altitude means less dense air. Engines (whether piston or jet) rely on air - for piston engines, it's part of the fuel - air mixture for combustion, and for jets, it's for compression and combustion. Less dense air means less oxygen for combustion, so engine performance decreases. For climb performance, lift is generated by the wing moving through the air (\(L = \frac{1}{2}
ho V^{2}S C_{L}\), where \(
ho\) is air density). With lower air density (\(
ho\)), for a given speed \(V\), wing area \(S\), and lift coefficient \(C_{L}\), the lift is lower. So, the aircraft has to fly faster to generate the same lift, which is harder during climb. For takeoff, the takeoff run is longer because the lower air density means less lift is generated at a given speed, so the aircraft needs to accelerate to a higher speed to get enough lift to take off.

Answer:

B. It reduces climb performance.