For a multiengine airplane with reciprocating, non-turbocharged engines, V(MC) does what with altitude?

V(MC), or minimum control speed, is the minimum speed at which a pilot can maintain controlled flight with one engine inoperative. For multiengine airplanes equipped with reciprocating, non-turbocharged engines, V(MC) tends to decrease with altitude.

This decrease occurs primarily due to changes in air density as altitude increases. As altitude rises, the air becomes less dense, which reduces the power output of the engines. Lower engine power results in reduced asymmetric thrust when one engine fails, leading to a lower speed at which the remaining engine can sufficiently counteract the yawing moment created by the dead engine. Consequently, pilots require a lower V(MC) at higher altitudes for safe flight control.

Considering the other options, V(MC) is indeed affected by temperature, as warmer temperatures can also reduce air density, though the question specifically focuses on altitude effects. The minimum control speed does not remain constant at different altitudes, contradicting the notion that it is unaffected. Lastly, the idea that V(MC) increases with altitude inaccurately suggests that control efficiency improves with less air density, which is not the case in terms of engine performance and control margins. Thus, the correct answer indicates the behavior of V(MC)