When Honeywell's newest auxiliary power unit (APU) – the 331-600 for the Airbus A340-600 – completed its flight certification programme, the Toulouse company issued a challenge.
Use the same 331-600 APU that had undergone accelerated endurance testing – and more than 7,900 starts – for the A340-600's final JAR/FAA cold weather operational testing in northern Canada.
Honeywell's Ulf Henriksson, vice-president of airframe systems, says: "Airbus challenged us to prove the maturity of the 331-600 APU at entry into service and we met the challenge by demonstrating that a heavily used engine would pass cold weather testing as well as a new engine."
Power
The APU performed flawlessly during 10-hour cold-soak starts and operated continuously for four days to provide electrical power and pneumatic power for aircraft maintenance, with more than 100h of operation.
This latest APU – with a shaft horsepower rating of 1,200 – is a derivative of Honeywell's proven 331-500. It delivers 431lb of air per minute at 54psi (3.72bar) and 126 Kw of electrical power. It will start and operate at altitudes up to 41,000ft (12,500m) and during development qualification and flight testing, the new variant APU accumulated more than 5,000h and 11,000 cycles of testing over and above the 14,500h of testing on its predecessor.
Source: Flight Daily News
