WASHINGTON Jan 28 Pentagon and industry
investigators have pinpointed a manufacturing quality problem as
the most likely cause of an engine failure that led to the
grounding of the Marine Corps version of the Lockheed Martin
Corp F-35 fighter jet, sources familiar with the
investigation told Reuters.
Pentagon officials are expected to finalize the finding and
the proposed fix at a meeting on Monday, said the sources, who
were not authorized to speak publicly. They said the F-35B
should be able to resume flights as soon as the "nonconforming"
parts supplied by a unit of Parker Hannifin Corp are
The grounding did not affect the Air Force or Navy versions
of the radar-evading new fighter since they do not use the same
The Pentagon grounded all 25 F-35B jets on Jan. 18 after a
propulsion line associated with the B-model's exhaust system
failed just before takeoff during a training flight at Eglin Air
Force Base in Florida.
The part in question enables actuator movement for the
exhaust system associated with the B-model's engine. Instead of
traditional hydraulic fluid, it uses fuel as the operating fluid
to reduce weight.
An initial inspection discovered a detached propulsion line
in the rear part of the engine compartment, and subsequent tests
showed the line was not built to specifications by Stratoflex, a
unit of Parker Hannifin.
"It wasn't built to specification as it should have been,"
said one of the sources. "But there's a very small population of
the tubes, and the problem should be fixed soon."
Stratoflex is a subcontractor to engine maker Pratt &
Whitney, a unit of United Technologies Corp, which
builds the engines for the single-engine, single-seat fighter
jet along with Britain's Rolls-Royce Plc.
No comment was immediately available from Stratoflex.
The speedy conclusion of the investigation is good news for
the F-35 program, which is racing to complete an aggressive
schedule of flight tests this year.
The F-35 program has completed about 34 percent of its
planned test flight program, but Lockheed is already building
production models of the new warplane.
Lockheed is building three different models of the F-35
fighter jet for the U.S. military and eight countries that
helped pay for its development: Britain, Canada, Italy, Turkey,
Denmark, the Netherlands, Australia and Norway.
The Pentagon plans to buy 2,443 of the warplanes in coming
decades, although many analysts believe U.S. budget constraints
and deficits will eventually reduce that overall number.