In most cases, the auxiliary power unit is running anyway, he said.

Usually, an auxiliary power unit is used to start the engines.

"It was in the area where the auxiliary power unit is located," he said.

The engines were shut down and the auxiliary power unit fired up.

First, he started the auxiliary power unit and watched the instruments begin to register.

In other cases, one battery showed an error reading and another, used to start the auxiliary power unit, failed.

There is also a special command version with additional radio equipment and an auxiliary power unit.

The auxiliary power unit burns about 4 pounds per minute, or a little more than half a gallon.

He engaged the auxiliary power unit and pushed the starter switch.

Research is done on fuel cell auxiliary power units.

They had built an even better auxiliary power unit than he had specified.

Each auxiliary power unit must be approved or meet the requirements of the category for its intended use.

A third engine acted as an auxiliary power unit.

The focus is now on the battery charger and the plane's auxiliary power unit.

Deliveries of this auxiliary power unit started in 1962.

Auxiliary power units were supplying the plane with heat and electricity from both sides.

Designs with auxiliary power units were also investigated but never developed beyond prototype stage.

David Becker hit the auxiliary power unit switch again.

About 9:00 p.m. the auxiliary power unit shut down, all lighting turned off, and emergency lights came on.

An auxiliary power unit is deployed and 271 passengers are put on flights with other carriers.

This was for fuel leaking from the auxiliary power unit cowling.

Shut down everything but your auxiliary power unit.

But Honeywell also makes auxiliary power units and aircraft instrumentation.

A heater for the fuel line leading to one of the shuttle's auxiliary power unit had failed.

Around 300,000 refrigerator trucks with auxiliary power units are on the road in the United States.