auxiliary power unit

British  

noun

1. an additional engine fitted to an aircraft to operate when the main engines are not in use

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Example Sentences

On the island, Laczko waited as mechanics tried to fix the plane’s auxiliary power unit that sits in the tail of the plane.

From The Wall Street Journal

The fix that American Airlines is installing addresses how the ducting connects to the A320’s auxiliary power unit and has been touted by Airbus as reducing “smell in cabin” events by as much as 45%, according to a presentation to customers early last year.

From The Wall Street Journal

Originally used as an auxiliary power unit for a commercial airliner, it has been turned into a testbed for new fuels developed in a laboratory next door.

From BBC

An auxiliary power unit used to power the plane without using the engines was not working, according to the safety board, and pilots decided to leave both engines running for a two-minute engine cool-down period while they waited to for the plane to be connected to ground power.

From Seattle Times

During maintenance work technicians Umit Atas and Luciano "Lucky" Ferriera spotted two pairs of eyes from inside the exhaust of an auxiliary power unit.

From BBC