If outside air temperature (OAT) increases during a flight at constant power and indicated altitude, what happens to true airspeed and true altitude?

If outside air temperature (OAT) increases during a flight at constant power and indicated altitude, what happens to true airspeed and true altitude?

• A. True airspeed decreases; true altitude decreases
• B. True airspeed increases; true altitude decreases
• C. True airspeed increases; true altitude increases
• D. No change in true airspeed or true altitude

Answer: (C)

When the outside air temperature (OAT) increases during a flight at constant power and indicated altitude, true airspeed experiences an increase due to the reduced air density associated with the warmer air. As the air gets warmer, it becomes less dense, which means that for the same indicated airspeed, the true airspeed must increase to maintain the same aerodynamic forces. This increase in true airspeed is important for maintaining flight efficiency, as the aircraft will cover more ground in the same amount of time. Regarding true altitude, as temperature rises, the actual atmospheric pressure at a given indicated altitude diminishes, leading to a situation where the aircraft is above the pressure altitude that it displays on its altimeter, which remains based on a standard atmosphere. Thus, in warmer air, while the aircraft maintains the same indicated altitude, its true altitude actually increases. Therefore, when considering the effects of an increase in OAT during a flight at constant power and indicated altitude, true airspeed will increase and true altitude will also increase, making this the correct interpretation of the scenario.

When the outside air temperature (OAT) increases during a flight at constant power and indicated altitude, true airspeed experiences an increase due to the reduced air density associated with the warmer air. As the air gets warmer, it becomes less dense, which means that for the same indicated airspeed, the true airspeed must increase to maintain the same aerodynamic forces. This increase in true airspeed is important for maintaining flight efficiency, as the aircraft will cover more ground in the same amount of time.

Regarding true altitude, as temperature rises, the actual atmospheric pressure at a given indicated altitude diminishes, leading to a situation where the aircraft is above the pressure altitude that it displays on its altimeter, which remains based on a standard atmosphere. Thus, in warmer air, while the aircraft maintains the same indicated altitude, its true altitude actually increases.

Therefore, when considering the effects of an increase in OAT during a flight at constant power and indicated altitude, true airspeed will increase and true altitude will also increase, making this the correct interpretation of the scenario.