The Bell Helicopter-Boeing team that builds the V-22 Osprey will hold a press conference Tuesday at the Farnborough Air Show with a number of senior Marine corps officers playing the starring roles, presumably to extol the virtues of the V-22 and its performance in Iraq.
They might not want to volunteer the following recent incident so we'll do it for them. It just so happens that on June 21 a Marine V-22 crew had a serious engine problem forced the crew to quickly find a place to land.
An internal Marine memorandum sent to us by a source describes
the problem delicately.
WHILE IN FLIGHT, PILOTS NOTICED THAT THE R/H ENGINE TORQUE WOULD NOT GO ABOVE 66 PERCENT. THE AIRCRAFT WAS UNABLE TO HOLD ALTITUDE, AND HAD TO MAKE AN EMERGENCY LANDING IN THE FIELD. AFTER REPLACEMENT OF THE ENGINE, A BOROSCOPE INSPECTION WAS CONDUCTED TO INSPECT THE ENGINE INTERNALLY. IT WAS DISCOVERED THAT COMPRESSOR BLADES WERE DAMAGED FROM POSSIBLE FOD INGESTION. A BOROSCOPE INSPECTION OF THE COMBUSTION CHAMBER SHOWED THAT THE LINER HAD BROKEN
INTO PIECES. THESE PIECES ENTERED INTO THE GAS GENERATOR, CAUSING SIGNIFICANT
DAMAGE.INTERNAL FAILURE OF THE ENGINE CAUSED FOR A
LOSS OF ALTITUDE CONTROL. THE AIRCRAFT WAS UNABLE TO STABILIZE OR HOLD AN ALTITUDE, AND WAS FORCED TO LAND. THIS COULD BE FATAL TO PERSONNEL ABOARD THE AIRCRAFT, AND CAUSE DETRIMENTAL DAMAGE TO THE AIRCRAFT. THE MISSION WAS ABORTED DUE TO THE FAILURE.
In other words, the engine was breaking up. Not a good thing. But whats more interesting is the indication that the troubled engine was still putting out considerable thrust, but the aircraft couldnt maintain altitude. The V-22 is supposed to be able to fly at least some distance and land on just one engine, but in this case it was unable to hold altitude while still getting significant power from the damaged engine.
We asked the Marines for comment on this incident and this
is what they said:
An MV-22 Osprey executed a precautionary landing June 21 in al Anbar province due to mechanical problems. Shortly after departing a forward operating base, engine problems prompted the crew to land the aircraft.
No personal injury or damage to the aircraft was sustained. The aircraft was repaired onsite and flew back to Al Asad Air Base without incident. Hostile fire was not involved.
The cause of the mechanical problem is currently being investigated.
Marine Medium Tiltrotor Squadron 162 is currently in their third month of deployment here at Al Asad Air Base. This is the first incident of its kind involving the MV-22 Osprey in Iraq.The aircraft continues to complete its mission as designed and prove its value as an essential asset to the Marine Corps' mission in Iraq.
"This environment is challenging for every aircraft
here in Iraq,"
said Lt. Col. Karsten Heckl, commanding officer, VMM-162. "The
maintenance Marines of VMM-162 have done an outstanding job keeping the Osprey in the fight through
preventative and routine maintenance."
We should point out a couple of things. One, it may have been the first precautionary (can you say emergency) landing due to an engine failure, there have been a number of incidents of rapid, unscheduled stops due to failed gearbox oil cooling systems, as reported in March by the Star-Telegram.
Second, the Marines have acknowledged publicly that they're wearing out V-22 engines far faster than anyone expected, both in the desert sands of Iraq and the far milder climes of the US.
-- Bob Cox
