Instruments

Radio Altimeter(RA)

Definition

An instrument that measures exact height above the ground using radar signals. Accurate below 2500 feet AGL, the radio altimeter is essential for approach minimums, GPWS, and autoland operations.

Related Terms

Altimeter

A barometric instrument measuring altitude by sensing atmospheric pressure chang...

Decision Height/Altitude(DH/DA)

The height during a precision approach at which the pilot must decide to land or...

Autoland

An automatic landing performed by the autopilot without pilot manual control inp...

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