The Sikorsky CH-53K heavy-lift helicopter program this week achieved “ready to load” condition with the successful light-off of its first auxiliary power unit (APU). The program will be ready to begin formal integration testing early next year.

The Hamilton Sundstrand APU is the secondary power system on the helicopter, providing power to a 45KVA generator and a 58-horsepower hydraulic pump and hydraulic starter, as well as providing bleed air to an environmental control system and main engine start system. It will be used for ground operations, main engine start, and conditions when main electrical power provided by the helicopter’s main generators is lost.

The APU is now being prepared for safety of flight testing and delivery of hardware for the ground test vehicle. According to Sikorsky, the APU development and qualification program will involve 13 APU engines–seven for Hamilton Sundstrand and six for Sikorsky.

The CH-53K will be a replacement for the U.S. Marine Corps CH-53E heavy-lift helicopter. More than 200 CH-53Ks will be produced for the USMC, Sikorsky said. Currently, the upgraded helicopter is in the system development and demonstration phase.