F-35 fleet cleared to fly after June engine fire prompted grounding

The Pentagon's most expensive
weapons program ever, the F-35 warplane, is
cleared for takeoff again.
The limited flight clearance, approved by Navy
and Air Force officials Monday, allows the
aircraft to fly with an engine inspection
regimen and restricted flight envelope
following the fleet's grounding after an engine
fire last month.
Defense Department spokesman Mark Wright
said in a statement Tuesday the restrictions
would "remain in effect until the root cause of
the June 23 engine mishap is identified and
corrected."
It had been hoped that the stealth fighter
would be able to make an appearance at the
famed Farnborough air show, under way now,
but Pentagon spokesman Rear Adm. John
Kirby said Tuesday afternoon that won't
happen.
"The Department of Defense, in
concert with our partners in the
U.K., has decided not to send
Marine Corps and U.K. F-35B
aircraft across the Atlantic to
participate in the Farnborough air
show," he told reporters. "This
decision was reached after a
consultation with senior leaders and
airworthiness authorities, despite the decision
by airworthiness authorities to clear the
aircraft to return to flight -- to limited flight."
The 2014 Farnborough International Airshow
began Monday, and runs through July 20 in
Farnborough, England. The opening day
brought $42 billion of orders and
commitments for commercial aircraft and
engines, according to a statement from the
show's organizers.
The F-35 was developed at a cost of nearly
$400 billion so far and beset for years by cost
overruns and delays. The so-called Joint
Strike Fighter was temporarily grounded
following a fire on the runway at Eglin Air
Force Base in Florida. No one was hurt.
Engine maker Pratt & Whitney worked with Air
Force investigators to inspect all engines in
the fleet.
"We have great confidence in the F135 engine
powering the F-35, and we have worked very
closely with DoD and the Services to return the
aircraft to flying status," Matthew Bates,
communications manager for Pratt & Whitney
Military Engines, said in a statement Tuesday.
The F-35's lead contractor, Lockheed Martin,
which is producing variants of the plane for
the U.S. Navy, Marines and Air Force, also
worked with investigators following the fleet's
grounding.
F-35 future
The Pentagon wants more than 2,400 of the
fighter jets ultimately, while hundreds more
are expected over time to go to allies such as
South Korea, Japan and Australia.
More than 100 planes have been built so far,
most for testing, but the program is still in its
development and training phases.
The military says the stealthy fighter will be
"the most affordable, lethal, supportable and
survivable aircraft ever to be used" by so
many services worldwide.
But its production has been controversial for
its soaring cost history -- the price tag has
nearly doubled from early estimates, to $135
million per unit as of last year, according to a
U.S. Government Accountability Office report
in March -- as well as its schedule, software
and other setbacks. Test flights began in
2007.
While all models have been grounded in the
past for various problems, the version for the
Marines, the F-35B, has had more issues.
Experts say that's mainly due to its design for
shorter takeoffs and vertical landings.
Richard Aboulafia, a Teal Group analyst, said
earlier this month that every component of the
F-35 overall "is pushing the frontiers of
technology" as engineers combine
extraordinary engine power with a lighter
weight design.
He said the program has made gradual
progress in recent years where glitches get
resolved pretty quickly compared with 18 to
24 months ago, when setbacks seemed to
come one right after another.
"It's a tremendously complex project," he said,
adding that cost issues remain a concern.