By: , published in aviationweek.com , Sep 12, 2014
Airbus and Pratt & Whitney are believed to be tackling a late-developing certification issue with the PW1100Ggeared turbofan in an attempt to stave off the looming threat of a delay to the first flight of the re-enginedA320neo.
The aircraft manufacturer, which declines to comment, has targeted September for first flight of the A320neo with the Pratt engine but, according to industry sources, may be forced to delay this because of unidentified concerns related to the PW1100G. Airbus had hoped to fly the test aircraft, MSN6101, as early as Sept. 5. However the modified A320neo, which was pictured taxiing under its own power at Toulouse on Sept. 1, remains on the ground.
The Pratt-powered A320neo is the first of two re-engined variants to be developed and will be followed by the CFM Leap-1A powered version which is due to enter flight test in 2015.
The exact nature of the problem remains unclear, though industry sources indicate the hurdles to first flight are associated with the last set of fan-related certification tests that Pratt was conducting in the run-up to certification.
Pratt declines to comment specifically on the allegations of any certification or testing-related concerns. The company says “we are working closely with Airbus as we prepare for first flight. It is premature at this time to say exactly when that will occur. We will provide more details as they become available.” MTU Aero Engines, a key partner on the PW1100G program, deferred questions to Pratt & Whitney.
Sources within the supplier and customer community prefer to remain vague. One senior executive of a major A320neo customer confirms information that there has been an issue during testing. The fact that customer representatives know about it indicates that Pratt & Whitney has been briefing key industry players.
Although the PW1100Gs underwent oil system checks to verify that none of the recent seal failures which occurred with the PW1500G on the Bombardier CSeries would appear on the A320neo, the Airbus engine development has otherwise proceeded virtually to plan until now. The first two engines for the compliance aircraft were delivered on schedule to Airbus, and Pratt has at least 28 engines in build or already in the test program.
As of early July the engine maker was progressing rapidly through the final items on the check list for European JAR-E and U.S. FAR Part 33 engine certification, with high and low pressure compressor stress tests, 150 hr. block tests, water and hail ingestion and a final brace of bird strike tests yet to be completed. Another major final test remaining was the fan blade out test, which Pratt was confident of passing successfully having already passed an earlier evaluation on a test rig.
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