Hudson APU
APU: Unsung hero of the engine world
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By: JOHN CROFT WASHINGTON DC 12:00 5 Oct 2010 Source: Flight
Auxiliary power units (APUs) do their dull and dirty work hidden away in aircraft tailcone compartments, unlike their turbine engine brethren connected to the wings or empennage.
On occasion however, the tables get turned.
On a bitterly cold Thursday in January 2009, the Honeywell 131-9A APU in the tailcone of a US Airways A320 that had just departed New York's LaGuardia airport came to the rescue after the aircraft struck a flock of geese. With both CFM56 turbofans damaged and the associated electrical generators eventually knocked off line, the APU during the final seconds of the ditching provided the power needed to keep the flight controls, displays and envelope protections in place to allow the pilot to touch down in the Hudson River in control and at the lowest possible airspeed.