BY Andrew Doyle/LONDON Guy Norris/LOS ANGELES

A POTENTIAL RIFT between the UK Civil Aviation Authority and the European Joint Aviation Authorities (JAA) over certification of the General Electric GE90 engine has added a new twist to the tight delivery schedule of the first Boeing 777 to British Airways.

The CAA has denied any rift, saying: "It is the JAA engine certification team that is asking for additional technical information to enable the JAA to complete its technical. There has been absolutely no unilateral contact outside the JAA evaluation."

In spite of the denial, 777 programme sources confirm the problem was addressed at a meeting between Boeing, General Electric and the JAA on 6 September. "The CAA went out, with a number of technical questions, concerning the GE90, which were not directed through the JAA," say the sources

The companies were concerned that the CAA's unilateral action, which reportedly concerned "legitimate questions", could be seen as being outside the terms of the reciprocity agreement between the JAA and the US Federal Aviation Administration. "The JAA said 'we will take care of this and we will do this by the proper procedures'," says the source.

The concerns of the CAA are largely echoed by the JAA, which is still examining the FAA's decision to allow GE to modify its blade-out tests earlier this year.

"We are not completely in line with the decisions of the FAA," says JAA secretary general Klaus Koplin, although there is "not a technical problem with the engine itself." He also says: "We are looking at the overall safety of composite fan blades, and looking at if there are any differences in applying the same rules as for metal blades."

Koos Van der Spek, JAA's certification director, says GE has been asked to supply additional data on blade-out tests to demonstrate compliance with JAA requirements. "We have decided to apply additional conditions," he says.

In urgent attempts to meet the 28 September delivery target, Boeing and British Airways are studying diverting the second GE90-powered test aircraft from dedicated early ETOPS (extended range twin operations) flights to certification duties.

The plan, if sanctioned, may save the delivery date but will push back BA's use of the 777 on ETOPS routes until 1996. Continued snags with the GE90 engine have delayed the start of the 1,000 cycle ETOPS programme which was originally due to be complete by 27 September. Boeing subsequently set the ETOPS effort back for completion in mid-December 1995, but is now expected to let it slip into early 1996.

"We are now sure we're going to have a delay to the ETOPS schedule, regardless of getting type inspection authorisation," admits Boeing. "At this point in time the focus is on basic certification."

The JAA has set a target date of 26 September for engine certification. According to Koplin, there is "a good chance" the GE-powered 777 will receive JAA type certification before 11 October - when BA's first aircraft is due to enter service. He adds that, "I would not say that we cannot match that date, but I'm not sure it is possible".

GE says that in-flight icing is the last remaining critical part of the flight test series to be achieved before certification. The test team will need to fly around the country in search of the right conditions to perform the test successfully.

Source: Flight International