Cutter Aviation MaXus Power Unit

You are in a Pilatus PC-12 at a remote airport with no FBO within hundreds of miles. It is hot and humid, and you will be flying passengers in need of medical attention. It would be helpful and appreciated to pre-cool the airplane and get the aircraft ready for flight.

This is the exact experience I’ve encountered flying during a disaster relief mission. Without running the engine, which isn’t always reasonable, there are no viable options – until now. Cutter Aviation, along with its partners, has embarked on a new design for an in-airplane ground power unit (APU) for the PC-12 and PC-24.

In talking with Dean Miller, Cutter’s STC Program Manager, they found a unique market need and developed an interesting solution. When I first examined the unit, it was like nothing I’d seen before. The unit couples a 45-horsepower Wankel Rotary engine with a starter-alternator which, through a rectifier, provides 300 amp (8.4KW) 28-volt DC power, more than enough to power many aircraft.

Cutter Aviation has teamed up with Advanced Innovative Engineering (AIE), HFE International, Acutronic, and U.S. Technical Consultants to design this APU for the aviation market. AIE is developing the engine and engine subsystems, while HFE is designing the controllers, sensors and testing. The alternator and power unit itself is developed by Acutronic, and U.S. Technical is assisting with the STC process. Cutter Aviation expects approval of the STC in 2023.

The APU will be installed in the empennage aft of the rear pressure bulkhead and is much quieter than turbine APUs. The installed unit weighs 92 pounds and has minimal impact on the Center of Gravity (CG). The potential operational benefit is impressive.

Powered by Jet A and lubricated with turbine oil, the APU also allows the operator quite a bit of flexibility. It is expected to operate on less than 1 GPH of Jet A with minimal use of oil. Of course, using the unit will also provide the capability to fully charge the aircraft batteries to facilitate the standard battery start process.

Whether you are at a remote airport or simply want to use your own aircraft power on the ground, the MaXus Power Unit will expand the flexibility of PC-12 and PC-24 aircraft.