What happens to an engine’s performance as altitude increases?

As altitude increases, engine performance generally decreases due to reduced air density. At higher altitudes, the air is less dense, which affects an engine's ability to intake the necessary air for combustion. This decrease in air density results in a reduction of the mass flow of air into the engine, leading to lower power output.

The behavior of engines at altitude is directly related to the physics of air and how internal combustion engines operate. Engines rely on the proper mixture of air and fuel to generate thrust; when there's less air due to lower density, the engine cannot perform optimally. This trend is particularly pronounced in piston engines and turbine engines, as they require a specific air-to-fuel ratio to maintain efficient combustion.

It’s important to note that while there may be various factors at play, such as temperature changes and the specific performance characteristics of different engine types, the overarching principle is that the decrease in air density is a primary reason for diminished engine performance at altitude.