Definition
Built-in features of an aircraft's flight control or autoflight system that automatically prevent the airplane from being flown beyond safe operating limits, such as excessive bank angle, pitch attitude, airspeed, or angle of attack. In fly-by-wire aircraft, the flight control computers intervene to keep the airplane within its safe flight envelope even when the pilot commands an input that would otherwise exceed those limits.
Plain English
Automatic safeguards that stop the airplane from being flown into a dangerous attitude, speed, or load — even if the pilot pulls, pushes, or banks too far.
Context Anchor
Seen in discussions of aircraft computers, engine controls, autopilots, and flight control systems.
Derivation
From 'protect' (Latin protegere, 'to cover in front') and 'function' (a task or role). The term names what these systems do: they cover the pilot from accidentally flying outside safe limits.
Why Pilots Care
They reduce the chance of engine or system failure by intervening automatically before limits are breached.
Grounding Statement
A protection function is the system stepping in when a limit is being approached or exceeded.
Intuition Check
Protection does not mean physical armor or damage-proof equipment here. It means automatic system safeguards that help prevent operation beyond approved limits.
Example Sentence 1
When the pilot pulled the sidestick fully aft, the aircraft's pitch protection function prevented the angle of attack from exceeding the stall threshold.
Example Sentence 2
Technicians tested the electrical protection functions after installing the new generator.