Sir - An article headed "New birdstrike rules worry GE" (Flight International, 15-23 December, 1993) reported that GE was concerned the company could be singled out for special conditions by the US Federal Aviation Administration, because of the use of composite materials in the fan.
At the time, GE said that "...GE's prime focus is just to make sure that there is consistency to the test requirements for all three manufacturers". It is therefore interesting that, one year on, GE has encouraged the FAA to treat it differently for test requirements.
The aerospace industry has decades of experience in both manufacture and operation of high-pressure turbine blades and yet - with all the sophisticated inspection equipment available -GE failed to find a casting defect in a blade that led to an engine failure during the 150h block test.
How can this same company convince the FAA to allow less stringent tests on its composite fan blade, although no real experience exists in either the manufacture or operation of such blades?
Michael Walton
Hinckley, Leicestershire, UK.
Source: Flight International
