Airbus is also gearing up to conduct static-line paratroop jump tests in Spain and France. The evaluation follows the first set of tests to determine the correct length of the static lines from the cargo ramp and the side paratroop doors. These also helped determine that the optimum deflection angle for the side-mounted baffles that protect jumpers and ramp dispatchers from the slipstream. “We found 30 degrees was the best angle,” says Jones.
Airbus Military still has to conduct air drops of cargo and paratroopers, as well as additional hard and soft landings and more cold and hot-weather tests, Vernet says. Flight tests of the aircraft's air defense systems, such as chaff and flares, also are scheduled.
“There's still some tidying up to do with the flight-control computer laws, which we will do in tests with an A330 and then we move into wet contacts,” Strongman adds. Overall there have been six iterations of the flight-control laws which have been progressively refined as the flight tests progress. The A400M system is based on those developed for the Airbus commercial line, and most closely resembles that of the A380. However, unlike its commercial brethren, the fly-by-wire A400M is configured with several adaptations to reflect its military role. “We have a law which changes gain for tanking. To modify the system we activate air-to-air refueling mode,” he adds.
Five A400Ms are flying in the certification program. Vernet says aircraft MSN4 will be kept for future tests, until at least 2018.
A400M engine maker Europrop International (EPI) meanwhile remains confident that the last-minute issue with the TP400 engines that kept the airlifter on the ground at Farnborough will be solved promptly. A few days prior to the show event, a diagnostic system detected metallic chips in one of the engines on MSN6—the first production-standard aircraft to appear at the show.
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 such few hours indicates a “one-off” flaw with the bearing rather than a more serious systemic issue.
However, the impact of the bearing analysis as well as investigations into an earlier incident in which an engine was shut down inflight following the onset of vibration “are impacting on functionality and reliability” (F&R) testing, confirms Henley. 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,” he affirms.
The vibration, which caused an engine to be removed during F&R testing in Oman, was “a completely unrelated issue” to a previous, similar vibration-related event. “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,” Henley adds.
The recent vibration problem involved a development engine, and not a production engine. A special test is planned to confirm this.
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 for this event says Henley. “We altered the rig to put in new gears, and we know we've got the cause.”