WASHINGTON (AP) _ The Pentagon announced Friday it will resume testing of the V-22 Osprey, which has been grounded since last year following two crashes that killed 23 Marines.
Pete Aldridge, undersecretary of defense for acquisitions, said while he still has ``some serious doubts about the safety, reliability and operational suitability'' of the V-22, flight tests on the helicopter-like aircraft are scheduled to resume in April 2002, in hopes of fixing the problems.
Testing is expected to last for about two years, he said.
``We have to make sure it's reliable, safe and operationally suitable _ it can fly off the decks of ships, it can land safely in very cluttered areas and it can fly at the speeds and conditions that we will have during combat operations,'' Aldridge said during a Pentagon news conference.
Once the Osprey can accomplish those things, the aircraft ``will provide our military, marines and special operation guys some unique capabilities.''
The Osprey is designed to take off and land like a helicopter, but to cruise like an airplane. Each V-22 costs about $89.7 million. Of the 20 Ospreys built so far, four have crashed.
The fleet was grounded indefinitely after four Marines were killed in December when their Osprey crashed and burned in woods near Jacksonville, N.C., on the way back from a training flight. A crash in Arizona in April 2000 killed all 19 Marines aboard.
In September, two Marine officers received letters of reprimand amid allegations that they ordered Osprey maintenance records to be doctored to exaggerate the troubled aircraft's readiness.
Aldridge said the tests would be comprehensive and focus on combat maneuverability and low speed hover conditions. It also will center on a phenomenon known as ``vortex ring state,'' a condition where an aircraft descends so fast that the air flowing through the rotor blades moves as fast as the air being pushed down. Investigators believe the condition caused the Arizona crash.
During a Pentagon news conference, Aldridge said the engineers who built the Osprey ``grossly underestimated the difficulties'' of the phenomenon. While the military failed to implement a proper test plan that would have found the problem, ``now we have one.''
The test flights will be ``event driven, as opposed to schedule driven,'' Aldridge said. ``We will not be driven by trying to accomplish something within a certain amount of time.''
Aldridge said while he personally had some doubts about the program, he said independent panels reviewing the Osprey could not find ``any fundamental reason why the airplane would not work.''
Aldridge added that the future tests would not use any troops.
The Marines last month estimated that the Osprey V-22 could be put into service in a year or two if flight testing resumed in the spring.
Congress recently passed an authorization bill with $1.044 billion for 11 Osprey aircraft.