Which term describes the process of measuring how altitude affects aircraft performance?

The correct answer is "Pressure Altitude Measurement," which refers to the method of assessing how changes in altitude influence the performance of an aircraft. As altitude increases, the density of air decreases, which can significantly affect engine performance, lift, and drag. Pressure altitude specifically measures the atmospheric pressure at a given altitude, allowing pilots and flight attendants to understand how high the aircraft is flying in relation to standard atmospheric pressure, typically at sea level.

In aviation, understanding pressure altitude is crucial for flight planning and performance assessments, as it directly impacts the aircraft's efficiency and safety during flight. The other options, while they may relate to altitude in some capacity, do not specifically encompass the broad and systematic approach that pressure altitude measurement provides in assessing overall aircraft performance in relation to varying altitudes.