Progress Reported On Latest A400M Problems

 - June 22, 2016, 5:20 AM

Airbus Defense and Space has delivered the first A400M airlifter that can conduct tactical missions. But the transfer of MSN33 to France marks only the fifth aircraft to be handed over this year, thanks to the previously acknowledged propeller gearbox (PGB) manufacturing fault. An interim fix is now flying, but a long-term solution may not be certified until the end of next year.

A significant number of Europrop TP400 engines have been replaced on the 26 aircraft delivered to date, and on the production line. PGB maker Avio Aero recommended inspections for cracks after 200 hours, and then every 20 hours. The A400M design features "down between engines" propeller rotation, and the fault potentially affects only those engines whose propellers rotate clockwise (two of the four on each aircraft).

Two engines with the interim PGB fix that are flying on MSN6 have now logged 100 hours each. Airbus hopes to certify the modification by September, which will increase the inspection interval to 600 hours. Engineers from Airbus Helicopters with long experience in gearboxes are have been drafted to help with solutions. Company officials insist that the basic engine turbomachinery is working perfectly. A final report on last year’s fatal accident is still to come, but there is no indication of a systemic fault in the Fadec.

Small cracks have also been found in some A400M center fuselage frames, made of a particular aluminum alloy. They have apparently been caused by chemical and environmental conditions. This has prompted another inspection regime, but the alloy is being changed beginning with MSN70. Airbus is hoping that the frames of earlier production aircraft can be replaced during scheduled maintenance.

Tactical mission capability is being cleared in gradual increments. MSN33 can aerial-deliver pallets or containers weighing eight tonnes, but that total should reach 24 tonnes by September. It can drop 25 paratroopers, a total that should soon rise to 40, and to 58 by year-end. The aircraft’s defensive aids subsystem has a Step 1 capability. It can refuel fighters and other transports, and there is some better news about the A400M’s ultimate ability to refuel helicopters. A new longer hose is to be test-flown.

A tactical ground collision avoidance system (T-GCAS) was certified for the A400M last month. It uses a precise digital model that extends across areas large enough to cover a complete low-level flight. It takes all flight configurations into account, and is valid down to 500 feet in IMC and 150 feet in VMC, or to 15 feet during low-level delivery.