Marines declare Osprey aircraft safe for return to flight

WASHINGTON -- One month after the MV-22 Osprey crash that killed 19 Marines in Arizona, the Marines are ready to resume flying the hybrid aircraft that takes off and lands like a helicopter but flies like an airplane.

''I feel confident we can put them back in the air,'' Gen. James L. Jones, the Marine Corps commandant, said in an interview Tuesday. ''Everything appears to have been working normally'' at the time of the accident.

Jones said families of the 19 victims, as well as members of Congress, have been told that investigators have found no evidence of mechanical, engineering or structural flaws in the Osprey.

''We see no problems whatsoever with the aircraft,'' Lt. Gen. Fred McCorkle, told a news conference.

McCorkle said investigators have concluded that the crash was caused by a loss of aerodynamic lift that forced the aircraft into a fatal nose dive as it was about to land.

For reasons that are not yet clear, the Osprey -- with a crew of four plus 15 Marines as passengers -- descended too rapidly toward a small airport at Marana, Ariz., McCorkle said. It was descending at more than 1,000 feet per minute, he said, compared to the maximum recommended rate of 800 feet per minute.

As the pilot executed an angle bank of between 5 and 15 degrees right at about 280 feet off the ground at about 8 p.m. local time, the aircraft encountered an aerodynamic phenomenon known as ''power settling,'' and four seconds later it nose-dived into the ground. McCorkle said this condition was similar to an engine stall and seemed to be related to the excessive rate of descent, a slow forward airspeed and the banking maneuver.

McCorkle said the ''power settling'' problem was not unique to the Osprey, and that pilots are trained to avoid it.

Both Jones and McCorkle said investigators were not yet prepared to ascribe the accident to pilot error. They said more study was needed.