Pratt & Whitney successfully completed FAA FAR 25 flight testing at Boeing on the company's 94-inch fan PW4000 engine. The testing took place at Boeing Field in Seattle, Washington. The testing centered on the incorporation of a new high compressor case design that was FAA FAR 33 certified in November 2002. The new "ring case" design is a series of one-piece rings that replaces the original case that had been built with two to four segments around the circumference of the engine's high-pressure compressor.

The new design is aimed at eliminating compressor surge at high power take-off, by providing more rigorous tip clearance control, and is based on Pratt & Whitney's 112-inch PW4000 engine design which has proven experience with 3 million hours and 1.5 million cycles of surge-free operation. The new design is being incorporated into new production engines and will be made available to airlines for incorporation at overhaul beginning this March.

"We are extremely pleased with the new ring case performance," said Jean Colpin, Vice President of Commercial Engine Programs. "This FAR 25 flight testing follows one of the most extensive testing programs in the history of Pratt & Whitney completed at FAR 33 certification late last year. Early indications suggest that we are exceeding expected fuel burn efficiencies and EGT margins and we are confident that this will help us surpass our airline customers' expectations."

During the FAR 33 certification testing, the test engines performed flawlessly for over 200 hours of flight-testing on a Pratt & Whitney purchased Boeing 747 flying test bed. The certification engines also endured over 2500 cycles at maximum operating conditions proving the durability of the robust design.

Pratt & Whitney expects to receive official certification of the new ring case on all Boeing 94-inch PW4000 powered aircraft this year. There are approximately 2200 94-inch fan PW4000s in service on 600 commercial aircraft around the world. They are used on Boeing 747, 767 and MD-11 aircraft and the Airbus A300/310 series. With an In-Flight Shutdown Rate (IFSD) of .006 and a dispatch reliability rate of 99.95%, the PW4000 is reportedly one of the most reliable engines in service today.

FMI: http://www.pw.utc.com