Starting Power: Honeywell APUs Stronger Than Ever At 75

No one remembers who first came up with the idea of using a small gas turbine engine to power aircraft electrical systems and provide airflow for cabin pressurization, air conditioning and deicing. But there is no doubt that talented engineers at Honeywell legacy company Garrett AiResearch ran with the idea and created the first turbine-powered auxiliary power unit (APU) 75 years ago.

That first APU was the Garrett GTCP85, which is still flying today. The GTCP85 was a derivative of the company's original small gas turbine engine, the GTC43/44, which entered production in 1948 and in 1950 provided compressed air to start the main engines and drive the electrical systems on a Convair P5Y aircraft.

More than 500 GTC43/44 engines were eventually manufactured for various applications, including onboard and ground-based power generation. More importantly, the company’s first successful turbine gas engine gave flight to the APU, a flight critical component that makes flying safer, more efficient and more comfortable for millions of people every day.

Our latest APUs, like the HGT1700 that flies on the Airbus A350, truly represent the state of the art and are much more powerful, efficient and reliable than previous generations of secondary power systems. The HGT1700 features variable speed capability to increase starting power while lowering specific fuel consumption by 6-10%.

Over the last 75 years we have seen a constant increase in the demand for power on all types of aircraft. This trend will likely continue as aircraft become more connected, electric and autonomous. With this in mind, Honeywell is already working on new secondary-power solutions that will meet the needs of the next generation of aircraft for APUs that are even more powerful, reliable and fuel efficient than the ones we have today.