Definition
A cockpit instrument that warns the pilot when the aircraft is approaching or deviating from a preselected altitude. The pilot dials in the target altitude, and the alerter provides visual and/or aural signals as the aircraft nears that altitude and again if it drifts away from it after capture.
Plain English
A device in the cockpit that lets you set the altitude you want to fly at, then beeps or flashes to tell you when you're getting close to it and again if you accidentally climb or descend away from it.
Context Anchor
Used during climbs, descents, and level-offs, especially in instrument flying when the pilot must capture and maintain assigned altitudes accurately.
Derivation
Altitude comes from the Latin altus, meaning high. Alert comes from an old warning sense meaning watchful or on guard. Together, altitude alerter means a system that keeps watch over a selected height.
Why Pilots Care
Helps maintain precise altitude compliance, reducing the risk of airspace violations or loss of separation from other traffic.
Intuition Check
Do not assume an altitude alerter flies the airplane for you. It warns you about altitude; the pilot or another flight control system must still control the climb, descent, or level-off.
Example Sentence 1
After being cleared to climb to 8,000 feet, the pilot set 8,000 in the altitude alerter so it would chime as the aircraft approached level-off.
Example Sentence 2
An alert from the altitude alerter prompted the crew to correct a 200-foot deviation.