July 12, 2012
Credit: Photo: Airbus
Europrop International (EPI) is confident that an issue with the TP400 engines that prevented the Airbus A400M from flying at the Farnborough air show will be solved promptly, and will not threaten the military airlifter’s scheduled 2013 entry-into-service.
In the days prior to the show, a diagnostic system detected metallic chips in one of the engines on MSN006, the first production-standard A400M appearing at Farnborough. The debris indicated deterioration on one of the unit’s roller bearings, says Europrop President Simon Henley.
The engine-maker believes the occurrence of deterioration on a TP400 with so few hours indicates a “one-off” flaw with the bearing rather than a more serious systemic issue.
Nevertheless, Henley says Airbus Military decided as a precaution to show the A400M as a static display, rather than subject the engines to further loads. In the meantime, analysis is being conducted on the suspect engine and bearing “as we speak,” Henley says. Engine problems also prevented the airlifter from flying during last year’s Paris air show.
The bearing analysis, as well as investigations into an earlier inflight shutdown caused by vibration, “is impacting on functionality and reliability” (F&R) testing, Henley confirms. The interruption, which took place roughly halfway through the 300 flight-hour F&R phase, will delay delivery of the first production aircraft by a month, he adds. However “it will not impact entry-into-service with the French air force.”
The vibration that caused an engine to be removed during F&R testing in Oman was “a completely unrelated issue” to a previous, similar vibration-related event, Henley stresses. “But this was a different cause. We have done comprehensive testing to the point where I can say with confidence that the modification we’ve done for another reason will take this issue away,” he says.
The recent vibration problem involved a development engine, and not a production engine. “We’re a couple of weeks away from a final test to prove that,” Henley notes.
To verify the source of vibration, gearbox system developer Avio modified a test rig in Turin, Italy. The rig, originally developed to investigate the initial resonance problems in 2011, was brought back into action for this event, Henley says. “We altered the rig to put in the new gears, and we know we’ve got the cause.”