Plain English Meaning

If one engine quits, this system automatically turns the dead engine's propeller blades edge-on to the wind so they stop windmilling and stop creating drag — without the pilot having to do anything.

Full Definition

An automatic system on a multi-engine turboprop airplane that senses a sudden loss of power on one engine and, without pilot action, drives that engine's propeller blades to the feathered position to minimize drag.

Context Anchor

Seen in multiengine airplane training, especially when discussing engine failure, propeller drag, and minimum control speed with one engine not producing power.