FAA Private Pilot Airplane (PAR)Weather Theory and ServicesEasy
As density altitude increases at a given airport, what effect does this have on aircraft performance?
- ATakeoff distance increases and climb performance decreases
- BEngine and propeller efficiency both increase
- CTakeoff distance decreases and climb performance improves
- DTrue airspeed decreases for a given indicated airspeed
Show answer & explanationAnswer & explanation
Correct answer: A. Takeoff distance increases and climb performance decreases
High density altitude means the air is less dense, reducing engine power output, propeller efficiency, and wing lift. This results in longer takeoff and landing rolls and reduced climb performance.
Why the other options are wrong
- B. Efficiency decreases, not increases, in thinner air.
- C. This is the opposite of what happens with high density altitude.
- D. True airspeed actually increases relative to indicated airspeed at high density altitude, not decreases.
Density Altitude Effects on Performance
High density altitude (thin, less dense air) reduces engine power, propeller thrust, and lift, degrading overall aircraft performance.
- High density altitude = longer takeoff/landing rolls
- Reduced climb rate and lower service ceiling
- Caused by high elevation, high temperature, high humidity, low pressure
Memory trick: Thin air = poor air (performance)