Definition
Autopilot functions that automatically maintain a selected pressure altitude by commanding pitch adjustments to keep the aircraft level. When engaged, the autopilot uses inputs from the air data system to detect deviations from the captured altitude and applies elevator corrections to hold that altitude within published tolerances.
Plain English
An autopilot setting that keeps the aircraft locked at one chosen altitude without the pilot having to fly it by hand.
Context Anchor
Seen in autopilot use, instrument flying, and turbulence guidance, including procedures for an inadvertent thunderstorm encounter.
Derivation
Altitude comes from the Latin altus, meaning “high.” Hold means “to keep.” Mode means “a way of operating.” Together, the phrase means a way the aircraft’s automatic system operates to keep a chosen height.
Why Pilots Care
Using these modes correctly prevents unintended climbs or descents that could lead to terrain conflicts or loss of aircraft control in convective weather.
Grounding Statement
In bumpy air, altitude hold tries to keep the airplane on one height instead of letting it move up and down with the air.
Intuition Check
Altitude hold does not mean the airplane will stay perfectly smooth or protected from turbulence. It only means the system is trying to maintain a selected altitude, and that effort may be undesirable in very rough air.
Example Sentence 1
After leveling off at 8,000 feet, the pilot engaged altitude hold mode and began monitoring the cruise instruments.
Example Sentence 2
Switching from vertical speed to altitude hold mode allowed the autopilot to stabilize the aircraft in the turbulent air mass.