Definition
A device installed in an aircraft that detects the sudden deceleration or impact forces of a crash and automatically triggers the Emergency Locator Transmitter (ELT) to begin broadcasting a distress signal.
Plain English
A small sensor that feels the sharp jolt of a crash and switches the emergency beacon on by itself, so it works even if the pilot is unable to.
Context Anchor
Seen in discussions of Emergency Locator Transmitters, especially how an ELT activates after an accident or hard impact.
Why Pilots Care
It ensures the ELT sends a distress signal without any action from the pilot, speeding up search and rescue after an accident.
Intuition Check
A crash sensor does not decide whether an event is officially a crash. It reacts to strong impact or sudden stopping forces that are large enough to trigger the ELT.
Example Sentence 1
After the hard landing, the mechanic inspected the ELT to make sure the crash sensor hadn't been triggered.
Example Sentence 2
During inspection the mechanic checked that the crash sensor would trigger the ELT under simulated high-impact conditions.