Bearing up: Airbus Military's 'Grizzly' nears civil certification

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Flight test activities with the Airbus Military A400M ­transport remain on track for completion by the end of 2012, with fixes having recently been agreed to ­resolve two separate ­engine issues which affected the programme earlier this year.

Updating the progress made using four "Grizzly" development aircraft for the first time since the type's restricted appearance at the Paris air show in June, Airbus head of flight operations Fernando Alonso said the fleet had logged 784 flights and 2,380 flight hours by 20 October.

Recent highlights included ­clearing water ingestion testing, making take-offs and landings under high crosswind conditions and performing the first low-level flights, down to 330ft (91m) at 280kt (518km/h).

Water ingestion testing proved that the highest wake experienced - at about 80kt - would not reach the aircraft's Europrop ­International (EPI) TP400-D6 engines. However, a minor design tweak will be required, as a link on the main landing gear door structure broke after water forced its way through a gap between the structure and a rub pad.

 

© Airbus Military

The European airframer's chief test pilot military Ed Strongman said the A400M's crosswind handling has been demonstrated to 25kt, ­gusting to 37kt on take-off and 26kt and 34kt respectively on landing. "The engines behaved immaculately," he added.

Such tests are being performed as Airbus Military works to complete the tasks required before securing civil type certification from the European Aviation Safety Agency - a target which it had previously set for completion ­before the end of this year.

"We are advancing very quickly towards the end of [civil] certification testing," Alonso said at the company's flight test centre in Toulouse, France. "I cannot say if we will finish on 10 December or 10 January [2012]. We will finish as soon as we can."

But the A400M's overall ­schedule - to complete 3,700h of core flight testing before deliveries can commence - has been threatened by several issues. The first arose in late 2010, when artificial ice shapes installed on the wing leading edges of aircraft MSN1 caused a large amount of buffeting as disturbed air hit the horizontal tail. This required a ­refinement of the sections of the composite wing which would need anti-icing equipment installed to take bleed air from the engines. Alonso said the work took about six weeks to complete, and was "really penalising on the programme."

The new configuration will be installed on MSN2 early next year, followed by all production aircraft. MSN1 has been held ready since August to complete the four more flights needed under natural icing conditions.

Engine supplier EPI has also resolved two engine issues, one of which was behind the decision to limit the A400M to making just one brief public ­flying ­appearance at Le Bourget.

EPI president Simon Henley revealed that the uncommanded in-flight shutdown of one of MSN1's engines on 6 June was traced to a fatigue crack in the tooth fillet radius on an idler gear, and caused by a resonance issue. A new software algorithm will alert the crew if an engine approaches the same conditions in flight again, and an upgraded idler gear design will be installed from November.

 

© Airbus Military

A high-pressure compressor blade fatigue fault also required three test engines to be removed from A400Ms earlier this year. The problem occurred at ground idle due to wake separation from the engine's variable inlet guide vane. A software patch will prevent a repeat occurrence, and an upgraded inlet vane design will be used on production aircraft.

EPI is to launch series production of the TP400 late this year, and deliver the engines for the programme's first customer aircraft in early 2012. A crucial enabler for handing this A400M over late next year will be the availability of a fifth and last Grizzly. MSN6 had been expected to fly recently with a production-standard cargo hold, but Alonso ­confirmed Airbus Military is ­assessing whether to delay this until early 2012. "Our priority is to get it in a configuration for ­testing," he added.

The aircraft will perform key military tests, including equipment loading, cold weather operations in Sweden and high-altitude testing in La Paz, Bolivia, before completing 300h of ­"functioning and reliability" testing. Other work to be performed using the development fleet next year should include grass landings in Germany, gravity load drops and receiving fuel in flight for the first time.

Alonso is confident that the A400M will meet its service entry goal. "We are delighted with how the aircraft is performing," he said. "We have removed most, if not all of the risk."