Farnborough A400M Engine Glitch Only On Test Aircraft
The problems with the A400M’s TP400-D6 turboprop engine that caused the airlifter to be scratched from this week’s Farnborough International flight demonstrations will slow civil certification and first delivery of the aircraft, but are not expected to delay its entry into service with the French air force next year. Production aircraft do not have the same issues.
Simon Henley, president of engine manufacturer Europrop International (EPI), said here yesterday that gearbox and bearing issues–unrelated to the gearbox problem that relegated the A400M to the static display at last year’s Paris Airshow–have interrupted a 300-hour functional and reliability (F&R) testing regimen required for European Aviation Safety Agency (EASA) civil type certification of the airlifter. In turn, that interruption will delay, “by a matter of weeks,” delivery of the first production aircraft by Airbus Military to the French Armée de l’Air originally targeted for the end of the year.
EPI, the collaboration of ITP, MTU Aero Engines, Snecma and Rolls-Royce, was about halfway through F&R testing with Airbus when the engine problems arose. The company has accumulated 20,000 total engine test hours on the TP400-D6, including 14,000 engine hours in flight.
In a briefing for reporters on Wednesday, Henley said EPI was able to resolve the gearbox problems from Paris last year in a matter of weeks, and then it designed and tested modifications by the end of the year. These are embodied in the MSN6 preproduction aircraft that flew last Saturday at the Royal International Air Tattoo in Gloucestershire, UK, but was sidelined here at Farnborough. Henley expressed confidence that EPI would resolve the latest issues as expeditiously as the earlier ones.
“The pace at which we can tackle these issues is proven. With what I know now about the technical issues we have around us at the moment, I’m absolutely confident we’re talking the same sorts of time scales,” Henley said. “By no means am I complacent about the fact that we have issues around us now. I can’t say they’re welcome. But nonetheless…we’ve demonstrated our capability to fix [problems].”
Specifically, Henley said a gearbox vibration problem that led to an in-flight engine shutdown in Oman this past April is “similar in nature but not in cause” to the 2011 gearbox issue. Comprehensive testing has identified the problem and “modifications we have done for another reason take this problem away” for production-standard aircraft. He said EPI is close to proving “to a certification level” that the latest problem is confined to development aircraft, and not to MSN6 and subsequent aircraft. This conclusion will be finally tested in “a couple of weeks.”
In addition, last week EPI discovered early signs of engine bearing deterioration from metal chips appearing on chip detectors on the MSN6 aircraft. Because the problem arose at a low number of engine hours, “it tends to point me to a one-off issue rather than systematic [problem],” Henley said. The analysis is ongoing. “That is the reason why we’ve agreed with Airbus that doing, in particular, the high-torque, high-energy maneuvers involved with flight testing is just not worth it for the program. Frankly, the main thing to have here is an aircraft that is production standard that people can actually see. That’s a decision we took together.”
Henley said still another vibration problem identified this spring and associated with the engine’s high-pressure compressor has been addressed through the manufacturing process. He said engines coming from assembly were found to marginally exceed the established vibration limit by 5 microns. However, the last engine delivered tested within vibration limits. EPI has delivered five of the 14 production engines planned this year.