Plane Sense 3 March_FinanceNov 19/02/2013 12:47 Page 3
HONEYWELL 131-9A APU
challenge the APU’s reliability and longevity. Down-low atmospheric pollutants, corrosives, salt air, atmospheric moisture and particulates challenge the durability of every part of the APU that sees airflow. Dirty air impinges on both the engine compressors and power compressors, as well as challenging the durability of surfaces exposed to the airflow – from the screened inlets to the compressors through the exposed edges of combustion chambers and continuing through the hot, white-hot, highvelocity, high-pressure airflow through the power-turbine wheels. Beyond erosive and corrosive impact of the atmosphere the solid and chemical contaminants attack APU materials at levels micro- and macroscopic, alike – anywhere corrosion can get a molecular grip. Yet sitting idle at altitude for hours on end could create difficulties pressing the APU into service aloft, too. After cold soaking in the thin, frigid air of the flight levels the temperature swing upon start-up adds its own stresses to all the rotating parts, compressors, power turbines, all the metal alloys subjected to sudden application of high-pressure air heated to white-hot temperatures. At least up high it is clean air, though…
HONEYWELL Offering 20 basic APU models and 41 variations, Honeywell may be the most-familiar APU provider in the market. Honeywell APUs are installed on the majority of aircraft worldwide because the company has delivered more than 64,800 units for more than 150 applications over the past 60 years. 85 Series: The 85 series APU revolutionized commercial air travel as the first APU to be installed in an aircraft. Previously, commercial air crews used a ground-based source to provide electrical power and comAdvertising Enquiries see Page 8
THE LEGENDARY HONEYWELL 85 SERIES APU
pressed air for engine starting. The 85’s first installation was in a Boeing 727 back in 1963. An aerospace industry landmark, the 30,000th production unit was delivered in 1996 (of course many product improvements had been made over the years since the first). The 85 series APU was inducted into the Smithsonian Institution for being the world’s most widely used aircraft APU, and today it is currently being used to test advanced materials that increase engine life. Additionally, Honeywell created its original 131-9D APU specifically for the Boeing MD-90 airplane, and the 131-9A arrived in January 1998 designed for installation in Airbus A320 series jets. Meanwhile, the RE220 demonstrates Honeywell’s advances in aircraft system integration by being the first General Aviation APU to communicate with the aircraft’s maintenance data acquisition unit (MDAU). Linking the MDAU to the APU gives pilots and maintenance technicians a window through which they can monitor APU performance and troubleshoot faults from the aircraft flight deck. Honeywell’s largest commercial aircraft APU is the 660, designed specifically to start the massive engines used on the Boeing 747 airplane. In addition, this workhorse drives two electrical generators that provide power to the aircraft.
HAMILTON SUNDSTRAND More than 825 Hamilton Sundstrand APS2300 APUs have been delivered to more than 70 operators of Embraer 170/190 series aircraft, while more than 1,800 APS3200 APUs were delivered to more than 155 operators for their fleet of Airbus A320 aircraft. The company’s APS5000 APU, meanwhile, works aboard the new Boeing 787 Dreamliner, producing an enormous 1,100 www.AvBuyer.com
shaft horsepower for its various air and electrical functions – the Dreamliner is predominantly electrical in operation.
THE CHALLENGES OF TOMORROW The world is on a collective drive to living greener, to reducing our “carbon footprints” while improving the operating environment for those working around noisy processes, and both APU makers have been in business to meet those challenges and implement improvements to their products’ performance. Noise has long been a leading source of disconcertion. Between the standards imposed by regulators and the pressures of customer demands, the sound output of APUs has been on a steady decline. Operating economics present another front – one being met by Honeywell and Hamilton Sundstrand on their own terms. Today’s generation of APUs enjoy a higher level of fuel efficiency than models that were new only a few years ago. The efficiencies of the newer APUs also accompanies reduced pollutants from the engine’s exhaust – a product of improvements in induction, mixing and burning the fuel used. Smaller and lighter can only take you so far as you move down the chain to the level where on-board batteries can meet all but the most-demanding needs. But continual improvement will remain a hallmark for a product family that already enjoys overhaul times in the 12,000-hour-plus range. Operators even enjoy the formidable advantage of by-the-hour maintenance and warranty programs for APUs, underwritten by companies including the OEMs as well as independents such as JSSI. Given the mushroom-like life APUs lead it is impressive how well they perform, and the importance of the roles they fulfill. ■ WORLD AIRCRAFT SALES MAGAZINE – March 2013
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