By BOB COX
STAR-TELEGRAM STAFF WRITER
Marine officials overseeing the V-22 Osprey program
say they now understand what happened last week when one
of the Bell Helicopter tilt-rotor aircraft was damaged
in an accident and have taken steps to prevent a
But they're still not sure why it happened.
Marines training to fly the V-22 in combat missions
have resumed flying even though the cause of the March
27 accident at a base in North Carolina has not been
James Darcy, a spokesman for the Pentagon office that
manages the V-22 program, said Wednesday that
investigators have concluded that the two pilots at the
controls of the aircraft did nothing to cause the
An official investigation of the accident is under
way and could take months.
Darcy said Marine pilots were conducting a routine
post-maintenance check of the V-22 when the aircraft's
engines suddenly gained power, and the aircraft lifted
off the ground and then slammed back down, all within a
span of perhaps five or six seconds. The hard landing
caused the right wing of the aircraft to snap off where
it joined the fuselage. No one was injured.
Officials are studying whether the $70 million
aircraft can be repaired and at what cost. The accident
has been designated a Class A mishap, meaning that
damage will exceed $1 million.
Darcy said the V-22 is designed so that the wing
breaks away in a very hard landing, relieving stress,
rather than have the entire wing structure collapse and
crash into the aircraft cabin.
Darcy said the chain of events began when the
aircraft's electronic engine controls suddenly signaled
the two turbine engines to dramatically increase power.
As the power increased, the aircraft's flight-control
computer automatically adjusted the pitch, or angle, of
the rotor blades so they were taking a bigger bite of
air, lifting the aircraft off the ground.
Even as the pilots attempted to react, backup engine
controls sensed the problem and reduced power, and the
airplane came down on its landing gear.
Initial reports said the aircraft reached an altitude
of nearly 30 feet, but Darcy said that was not the case.
"It actually went up about six feet."
Darcy briefed the Star-Telegram on the
accident by telephone after the V-22 program manager,
Marine Col. Bill Taylor, spoke to reporters in
Unknown is why the "full authority digital engine
controls" suddenly sent fuel surging into the engines to
increase power. Darcy said an engineering investigation
will look at computer software, electrical wiring and
Darcy insisted that an uncommanded power surge was
not unusual in helicopters.
But retired Marine helicopter pilot Bill Lawrence of
Aledo said he had never experienced such a thing in
hundreds of hours flying helicopters with electronic
engine controls. Lawrence was assigned to manage the
V-22 test program, but he retired before the first,
oft-delayed test aircraft was delivered.
"If it's a fairly regular occurrence, why haven't
they fixed the [engine controls]?" Lawrence said.
Lawrence said the Marines should ground the V-22s
until they know exactly what happened.
Darcy said that the accident has been replicated in a
flight simulator, and that V-22 pilots will be trained
to recognize the power surge problem and respond by
increasing power and gaining altitude until they can
gain control of the aircraft and bring it back for a
Engine manufacturer Rolls-Royce has also said it can
make changes to the engine-control software that should
prevent another accident, Darcy said, a process that
will take months for design and testing.