Commercial Pilot License (CPL) 2025 – 400 Free Practice Questions to Pass the Exam

In less dense air, the performance of an aircraft is primarily affected by the reduced availability of air molecules for engine intake and propeller efficiency. Aircraft engines rely on a constant supply of air for combustion, and when the air density drops, there are fewer air molecules available, which can lead to a decrease in engine power output.

Similarly, propellers require a certain density of air to generate thrust. In less dense air, propellers may not be as efficient, resulting in lower thrust and overall performance. The combination of these factors means that less dense air can hinder the aircraft's ability to climb, accelerate, and maintain altitude, which is critical for performance in various flight conditions.

While increased turbulence or other factors may influence performance, the fundamental issue with decreased air density is the direct impact on engine intake and propeller efficiency, which underlies the correct answer.