The Bell Boeing V-22 Osprey programme is facing an indeterminate delay to the start of full-rate production following the second fatal crash of a US Marine Corps tiltrotor in eight months.
The USMC has asked US Department of Defense acquisition chief Dr Lee Buchanan to delay the "milestone III" decision on starting full production until the cause of the 11 December accident can be determined. An initial order for 16 MV-22s and four CV-22s for the US Air Force was pending. After the crash, the USMC suspended flight operations of eight MV-22s, while the army has grounded its two CV-22s.
Meanwhile, defence secretary William Cohen is to appoint a "blue ribbon" panel of experts to review the programme. What impact the commission will have on a production go-ahead is unclear. "I think we're still going to have a milestone III, it will just come at a later time," says Lt Gen Fred McCorkle, USMC deputy commandant aviation.
The latest crash comes just months after an operational evaluation (Opeval) MV-22 crash in Arizona in April, killing 19 marines, and a recent independent assessment questioning the tiltrotor's maintainability and reliability. The USMC's own Opeval report, while pointing to the need for improvements, said the tiltrotor was ready to enter service.
April's crash was attributed to the pilot getting into too high a sink rate while in helicopter mode, generating vortex rings. The circumstances surrounding this latest accident, which killed all four marines on board, appear to be different. The crew issued a mayday distress call just before the controller lost contact with the MV-22, 3min flying time and 6.1nm (11.3km) from New River MCAS.
McCorkle says the MV-22 appeared to crash level to the ground while in airplane mode. The tiltrotor was on a ground controlled approach at night after completing an instrument mission. There was around 5.2nm of visibility.
Source: Flight International
