Guy Norris/SEATTLE

GENERAL ELECTRIC is investigating foreign-object damage (FOD) as being a possible cause of a surge experienced on a GE90 engine powering the first British Airways Boeing 777.

The incident took place immediately after take-off from Boeing Field, Seattle, on 4 May on a certification test-flight. GE says that the crew of the 777, WA076, was engaged in engine-operability-characteristics testing and was about to test for stall margins when the surge occurred.

Immediately after the surge, "...the crew pulled the throttle back, but the engine returned to running order, so power was put back on and the airplane returned to the field", says the company. "We're trying to evaluate what caused it and we really don't have an answer yet. We are going to look at FOD, including a bird, and the engine is being torn down to make sure," GE adds.

Borescopes of the engine have so far revealed no "visible damage" and no clues as to the cause. GE says that a spare engine is being fitted to WA076, the first to be powered by the GE90.

Almost 70 flights had been completed on WA076, the certification aircraft, before the incident. The aircraft is more than two-thirds through the 342 flight hours planned for type certification.

The problem forced Boeing to postpone a series of planned GE90 noise-measuring flights at Glasgow, Montana, as part of the certification requirements, but GE says that the incident does not affect preparations for the start of extended-range twinjet operations testing.

Source: Flight International