The US Federal Aviation Administration has approved plans by General Electric to conduct the critical fan blade-off tests for the GEnx engine for the Boeing 787 which involves detaching the blade further along its length, rather than right at the root as in normal blade-off tests.

The test, which is one of the final tests for FAR Part 33 engine certification, proves the inherent design of the engine and its structural ability to cope with the catastrophic loss of a blade at full power.

By allowing the test to be conducted using a blade that is detached slightly further away from the root, and which is therefore shorter, GE is able to maximize the weight advantages of using composite materials for both the blades and fan case. The FAA approval is therefore a vital milestone in its entire GEnx development strategy, particularly as this involves extending the use of lightweight composites to include the fan case for the first time.

GE GEnx test engine

The FAA Special Conditions approval covers the GEnx-1B54, 58, 64, 67, 70, 70/72, 70/75, 72, and GEnx-1B75 versions covering all currently planned 787 versions, and is based on the precedent established in 1995 when the FAA agreed on a similar set of rules for the GE90.

The above story is an abridged version of one available to subscribers of Air Transport Intelligence, Flight's premium 24h aviation news and data service.
More details of the GEnx fan blade tests will feature in next week's Flight International magazine, out on newsstands Tuesday 30 January.