Graham Warwick/WASHINGTON DC
Honeywell has begun flight testing its AS900 turbofan, under development to power the BAE Systems Avro RJX regional airliner and Bombardier Continental business jet.
The first flight, on Honeywell's Boeing 720 engine testbed, included performance and windmilling tests. During the 2h flight, the 7,000lb (31kN) thrust-class AS900 was operated at up to 93.6% N2 (engine speed). Windmill data was collected during the descent from a scheduled shutdown at 23,500ft.
"The engine met our expectations," says Jim Kidwell, director, AS900 engineering, at Honeywell (formerly AlliedSignal) in Phoenix, Arizona. Windmilling tests were "encouraging", he says, adding: "Windmilling is a critical parameter for the engine on both its applications."
Honeywell's 720 engine testbed has been refurbished and modified for the AS900 programme. A new pylon allows the complete propulsion system, including the nacelle, to be flown in its fuselage-mounted (Continental) and wing-mounted (RJX) configurations.
The company plans to accumulate 400h of flight testing over the next year, Kidwell says. Initial flights involve the second development, or "B", engine. This will be replaced towards the end of the month with the "F" engine, he says, a production-standard AS900 with more instrumentation allowing detailed evaluation of component and engine performance.
The AS900 programme calls for over 13,000h of ground and flight testing on 17 engines. Two cores and three engines have so far accumulated over 400h, and Kidwell says the programme is on schedule. First flight on the RJX is planned for November, and certification is scheduled for March next year, just ahead of the Continental's first flight, which has been set for April next year.
The AS900 will be certificated initially at 7,500lb thrust, he says, to provide margin for growth above the 7,000lb required for the RJX and the 6,700lb needed for the Continental. The engine will also enter service with mature inspection intervals of 3,500h and 7,000h for regional operators and on-condition maintenance for corporate operators, Kidwell says.
Honeywell, which is developing the AS900 with risk-sharing partners, has "aggressive" cost targets for the engine.
"Currently we're about 4% above, but I feel comfortable with our plans to pull that back down," Kidwell says.
Source: Flight International
