Which instrument is typically used to measure pitch performance?

The altimeter is the instrument typically used to measure pitch performance in an aircraft. It indicates the aircraft's altitude by measuring the atmospheric pressure outside the aircraft, which is crucial for maintaining a specific flight level. Pilots utilize the altimeter to determine how high they are above sea level and to adjust their pitch attitude accordingly to climb or descend.

Maintaining proper pitch performance is essential for safe navigation and flight operations, as it affects the aircraft’s vertical speed. In essence, while the performance in terms of airspeed, heading, and turns can be monitored with other instruments, the altimeter specifically provides critical data necessary for managing the aircraft's vertical position and ensuring altitude is maintained or altered appropriately.

Other instruments serve different purposes; the airspeed indicator measures the speed of the aircraft through the air, the heading indicator displays the aircraft's directional heading, and the turn coordinator indicates the rate of turn and coordination of the aircraft during maneuvers. None of these directly measure pitch performance as effectively as the altimeter does.