What happens to maximum range and maximum endurance as altitude decreases?

As altitude decreases, the maximum range and maximum endurance of an aircraft both increase. This phenomenon is primarily due to the relationships between altitude, air density, and engine performance.

At higher altitudes, the air is less dense, which leads to several factors affecting performance. The reduced air density means that engines may not produce as much thrust, as there is less oxygen available for combustion. Additionally, the aerodynamic efficiency of the aircraft can decrease due to the thinner air causing less lift at a given speed.

When altitude decreases, the air density increases, allowing engines to perform better and produce maximum thrust. This increase in thrust capabilities leads to improved performance, resulting in both longer maximum range and improved maximum endurance. The reason maximum range increases is due to the ability to maintain effective cruising speeds with better fuel efficiency; similarly, maximum endurance benefits from being able to fly at more optimal power settings for longer durations due to enhanced engine performance.

In summary, as altitude decreases, both the maximum range and maximum endurance improve due to enhanced engine performance and better aerodynamics associated with denser air.