Marine Corps News > MV-22 ACCIDENT INVESTIGATORS FOCUS ON LOSS OF LIFT: MARINES ANNOUNCE PHASED 'RETURN TO FLIGHT' PLAN FOR OSPREYS >
Posted 05/09/2000 03:16:40 PM --- More news articles
MV-22 ACCIDENT INVESTIGATORS FOCUS ON LOSS OF LIFT: MARINES ANNOUNCE PHASED 'RETURN TO FLIGHT' PLAN FOR OSPREYS
By Division of Public Affairs, HQMC
HEADQUARTERS, U.S. MARINE CORPS, WASHINGTON, DC (May 9) -- Marine Corps officials said today that a phenomenon known as "power settling" is now the focus of their investigation into the crash of an MV-22 Osprey aircraft that killed 19 Marines April 8 in Marana, Ariz.
As part of a regularly scheduled Defense Department news briefing, Marine Deputy Commandant for Aviation Lt. Gen. Fred McCorkle outlined what officials have learned since the accident. The general also announced a phased plan to resume flights of the MV-22 Osprey.
Following the accident, Marine Corps Commandant Gen. James L. Jones ordered an operational pause of all V-22 flight operations to allow investigators to analyze information provided by an onboard data recorder and to provide insight as to the cause of the accident.
Analyses of the data retrieved from the data recorder, called a Crash Survivable Memory Unit (CSMU), along with extensive engineering investigations have confirmed that all aircraft systems and software were operating properly at the time of the accident.
The data shows that in the last seconds of its flight, the mishap aircraft was in a high rate of descent at a relatively low forward airspeed. These characteristics can lead to a condition known as power settling (or vortex ring state) which can result in a loss of lift on the rotor system. Power settling is a phenomenon common to helicopter flight.
Officials continue to look at other possible causes such as settling with power and the effects of operating two aircraft in close proximity to each other in flight.
A thorough review by the Naval Air Systems Command, the Naval Safety Center and the Deputy Commandant for Aviation has found no structural or design flaws that preclude safe flight operations and the Marine Corps maintains complete faith in the safety of the V-22 aircraft.
As a result, Gen. Jones has lifted the temporary operational pause for instrumented models of the Osprey, known as Engineering, Manufacturing and Development aircraft, in the first of three phases in the resumption of flight of the MV-22. Developmental test pilots will continue to simulate and analyze possible causes of the accident.
Following continued analysis of flight operations and insights gained from further findings of the investigation, the Marine Corps will conduct a phased approach in its return of production MV-22s to flight status, initially with essential aircrew only, and eventually with passengers.
The MV-22 has safely flown more than 40 troop-lift missions and has carried more than 700 troops during operational evaluation flights.
To personally demonstrate his confidence in the MV-22, Gen. Jones plans to be aboard the first aircraft carrying passengers.
Marine Corps officials stressed the importance of informing the public about both the decision to resume flights and their commitment to the MV-22 Osprey aircraft.
They maintain the Osprey is clearly a much better, much safer, and much more capable aircraft than the Vietnam-era CH-46 and CH-53D helicopters that it will replace.
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