FAA sample question 4

FAA sample question 4 of 46 · Weather

What effect does high density altitude have on the efficiency of a UA propeller?

A. Propeller efficiency is increased.

B. Propeller efficiency is decreased.

C. Density altitude does not affect propeller efficiency.

Answer: B. Propeller efficiency is decreased.

High density altitude means thinner air. Each propeller revolution moves less air, so thrust and efficiency drop. Hot, high and humid conditions all raise density altitude.

The FAA published this sample set in August 2021. Our answers were checked against the current regulations and against the testing-supplement figures in September 2026.

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