On January 15, 2009, US Airways flight 1549, an Airbus A320-200 that took off from LaGuardia Airport in New York City for Seattle-Tacoma International Airport in Washington, flew through a flock of Canada Geese during its initial climb about three minutes into the flight. As a result of bird ingestion, the aircraft lost power on both the engines and with no possibility of making it to a runway, the pilot managed to ditch the aircraft in the Hudson River off midtown Manhattan with no loss of life. All 155 occupants were safely evacuated from the aircraft that was sinking slowly. The incident is known as the ‘Miracle on the Hudson’.

Narrating this to the visiting international media at Phoenix, Arizona, the Vice President, Propulsion Systems, Honeywell Aerospace, Ron Rich said the Honeywell auxiliary power unit (APU) on the US Airways flight 1549 had come in handy in the ‘miracle’. The APU operated in a moment’s notice.

Narrating this to the visiting international media at Phoenix, Arizona, the Vice President, Propulsion Systems, Honeywell Aerospace, Ron Rich said the Honeywell auxiliary power unit (APU) on the US Airways flight 1549 had come in handy in the ‘miracle’. The APU operated in a moment’s notice.

Range of Applications

For more than 50 years, APUs manufactured by Honeywell have delivered highly reliable electrical and pneumatic power for a wide range of business, regional and commercial aircraft applications. From main engine starting and cabin cooling to electrical power generation, Honeywell APU solutions employ leading-edge technologies and integrated system architectures to deliver higher performance and enhanced reliability with a reduced cost of ownership.

Rich mentioned that from the first flight in 1950 of the Honeywell APU, the company has since produced over 90,000 of which over 36,000 are in operation. The APUs have about 150 applications and the company has produced 20 models in seven families. From 100 HP to 1700 SHP (on the Airbus A350 XWB), Honeywell has the range. The 1700 SHP APU is Honeywell’s largest APU which is being certified and almost ready for entry into service. It is developing APUs for Bombardier C Series, Comac 919 and Irkut MC-21 aircraft. It has a strong presence in the single/narrow aisle market.

APU for New Aircraft

Jim Walker, Plant Director, who took the media around the APU assembly unit, mentioned that the team was working on APUs for Bombardier’s Challenger 300; Gulfstream G280 and later this year it would commence work on Embraer’s Legacy 650. A flight begins and ends with the APU. From the moment a passenger walks into an air-conditioned plane on the tarmac, to the time when the plane parks at the gate, the APU provides electrical air power to the aircraft for starting the main engines, enabling the air-conditioning system, energising lighting and flight equipment and more. The APU allows passengers to sit in comfort inside the aircraft while awaiting take-off.

Market Dominance

In the business aviation sector, there are about 9300 APUs and Honeywell accounts for almost 9,000 of these, indicating its dominance. In the defence and space segment, Honeywell has 9,000 APUs of the total of 18,000 in use. The stranglehold it has over the APU market is because of the huge benefits it offers – cabin comfort when the aircraft is on ground by providing cooling, cabin temperature, aircraft electrical loads and main engine starting. In flight, the APU stands ready to assist in case there is loss of power. It is environment-friendly and helps burn ten per cent less fuel. It produces three per cent less gaseous emissions.

Honeywell’s innovative event and usage-based aftermarket programmes can be customised to the customer’s aircraft needs and business requirements to improve APU reliability, while decreasing overall maintenance expenses. Additionally, the APUs,when installed fleet wide, are proven to lower operating costs through unit commonality, reduced mechanic training and decreased inventory requirements.

131-9 Series

For main engine starting power, pneumatic power and electrical power generation, the highly reliable 131-9 Series APU delivers robust performance, increased engine life and easy maintainability for lower costs of operation and ownership. Incorporating a two-stage axial turbine design, the patented effusion combustor and highly efficient 8:1 pressure ratio engine compressor, the 131-9 is designed to exceed narrow-body operator requirements. The 131-9B improves engine life by acting as a single starter/generator, using electrical power to start the APU and then transitioning to a generator once the APU is running. With quieter operation from noise reduction features integrated into the inlet, compressor and hot section design, the 131-9 provides a cost-effective APU solution for single-aisle Airbus and Boeing aircraft.

RE-220 Series

For aircraft with lower electrical and engine starting power requirements, the RE-220 Series APU is a highly efficient, reliable and cost-effective source of pressurised bleed air for environmental control systems and emergency electrical power. Demonstrating Honeywell’s advances in aircraft system integration, the RE-220 is the first general aviation APU to communicate with the aircraft’s maintenance data acquisition unit (MDAU) to allow pilots and aircraft mechanics to monitor and troubleshoot APU performance from the flight deck.

Small 36 Series

Providing advanced performance with lower total cost of ownership for business jet operators, the 36 Series APU uses a high efficiency compressor to provide greater on-wing reliability, improved main engine starting and enhanced high altitude electrical power capacity. Utilising a ported shroud compressor design, the 36-150 enables both higher pneumatic performance and shaft loads while reducing ground noise acoustics up to ten per cent. A variety of 36 Series APU models are available in a wide range of bleed air/shaft horsepower and size combinations to optimise the aircraft installation.

331 Series

The 331 Series APU provides high levels of reliability with economical maintenance, resulting in lower total costs of ownership for dual-aisle commercial aircraft. As the first electronically controlled APU in the industry, the 331 Series in-flight APU operation allows two-engine commercial aircraft to fly extended ranges, as the APU can provide emergency electrical power in the unlikely event of a main engine Integrated Drive Generator (IDG) failure. Design features include a three-stage axial turbine with a reverseflow annular combustor to increase efficiency, an eductor cooling system that improves reliability, and a compressor design optimised to be highly resistant to foreign-object damage (FOD).

The key benefits of Honeywell APU’s include reduced maintenance requirements for a decrease in direct operating costs, exceptional main engine start performance reduces wear and tear for main engine and components, superior fuel burn rates for lower total costs of ownership, more robust APU output for enhanced power generation, ongoing investments in reliability improvements based on direct input from OEMs, airlines as well as aircraft operators and dedicated support team with worldwide maintenance services and asset availability.

The Future

Honeywell is looking to the future to advance the 131-9 APU and continue to provide the best-in-class operational efficiency to customers. This next-generation APU will use new technologies to provide operators with up to ten per cent reduction in fuel burn, 25 per cent reduction in NOx emissions and more than 30 per cent increase in available electrical power. In the future, Honeywell’s APUs will power more than just internal systems. For the electric green taxiing system (EGTS), the APU will be tasked with powering the electric motors in the main landing gear, allowing an aircraft to push back autonomously and then taxi between the gate and the runway without even starting its main engines.