Pratt & Whitney is working to clear PW4000 surge prevention modification kits on Airbus A300/A310 and Boeing MD-11 and 767 aircraft following certification of the improvement for the 747.

US Federal Aviation Administration certification of the kit was achieved on the PW4056, 4060 and 4062 versions of the 2.38m (94in) fan diameter engine after more than 200 flight test hours on a company 747SP testbed, and over 2,500 cycles at maximum operating conditions. Clearance for the PW4052/56 and other versions powering the 767 will be certified by extension.

The modification is based on the "ring case" compressor design developed for the larger PW4084 powering the Boeing 777. It combats a take-off surge problem that has dogged the engine family for several years.

Source: Flight International