Definition
An aural warning system required on certain turbine-powered aircraft and large transport aircraft that alerts the pilot when the airplane exceeds its maximum operating limit speed (V-MO) or maximum operating limit Mach number (M-MO). The warning is typically a continuous tone or repeating signal that activates before structural or aerodynamic limits are reached.
Plain English
A built-in alarm that sounds when the aircraft is going too fast for safe operation, warning the pilot to slow down before reaching the airplane's speed limits.
Context Anchor
Seen in aircraft equipment discussions, especially when reviewing required instruments and systems for instrument flight or higher-performance aircraft.
Why Pilots Care
Exceeding structural or aerodynamic limits can cause damage or loss of control; the device gives immediate warning so the pilot can reduce speed before limits are breached.
Intuition Check
Do not read this as a general speed display. A speed warning device does not simply show speed; it warns when speed is too high for the aircraft’s limit.
Example Sentence 1
During the descent, the speed warning device sounded, and the captain immediately reduced thrust to bring the airspeed back below V-MO.
Example Sentence 2
On the preflight the crew tested the speed warning device to confirm it activated at the correct airspeed.