US Pease Air National Guard (ANG) has announced the successful completion of the first full replacement of a KC-46 Pegasus aircraft’s auxiliary power unit (APU).

It was executed by airmen and engine mechanics from the 157th Maintenance Group (MXG ) at Pease ANG Base in New Hampshire, US.

An APU engine is fitted in the back of the aircraft to provide power to start to the main engines.

It is responsible for generating electrical and compressed air power to support the cooling, heating and ventilation systems before the main engines start.

The unit can also be used for providing ‘electrical power or bleed air’ to restart the engines in case of in-flight engine failure.

The latest effort was performed to address issues with the APU of KC-46 Pegasus aircraft at Pease ANGB. The engine unit was having excessive vibrations that were causing the aircraft’s ductwork to shake.

157th Aircraft Maintenance Squadron commander major Alex Morris said: “We had been troubleshooting an error message that plagued us for many months.

“The mechanics worked through every possible part of the aircraft, and this was the last option.”

The procedure involved replacing the old APU with the same model.

During this process, the first engine was extracted by the team using a small crane and a fishing pole lifting equipment and while it was kept suspended, the team transferred the parts to the new unit.

Following the installation of the new APU, the deployed team is now preparing to send the faulty engine to Honeywell for further inspection. 

157th MXG engine mechanic master sergeant Dustin Bugado said: “Working on the KC-46 is also really different from the KC-135 aircraft. In a KC-135 there were notes on everything.”