Home » Aviation » Update: F-35 Cleared to Fly With Restrictions, U.K. Air Show Appearance Cancelled


Update: F-35 Cleared to Fly With Restrictions, U.K. Air Show Appearance Cancelled

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F-35A Lightning IIs from the 58th Fighter Squadron, 33rd Fighter Wing, Eglin AFB, Fla., perform an aerial refueling mission May 14, 2013, off the coast of northwest Florida. US Air Force Photo

F-35A Lightning IIs from the 58th Fighter Squadron, 33rd Fighter Wing, Eglin AFB, Fla., perform an aerial refueling mission May 14, 2013, off the coast of northwest Florida. US Air Force Photo

This post was updated to include additional Tuesday afternoon comments from Rear Adm. John Kirby.

The Lockheed Martin F-35 Joint Strike Fighter fleet has been cleared to fly within a restricted flight envelope after the jets were grounded following a June 23 fire that severely damaged an aircraft on take-off.

A problem with the jet’s Pratt & Whitney F135 engine caused the fire.

“Yesterday the air worthiness authorities for the U.S. Navy and U.S. Air Force approved the F-35 fleet to return to flight,” said Pentagon press secretary Rear Adm. John Kirby in a statement.
“This is a limited flight clearance that includes an engine inspection regimen and a restricted flight envelope which will remain in effect until the root cause of the June 23 engine mishap is identified and corrected.”

Undersecretary of defense for acquisition, technology and logistics Frank Kendall told reporters in London that the problem that caused the fire does not appear to be a fleet wide issue.

“We don’t see at this point what I call a systemic problem,” he said.

According to Kendall, the fire was a caused by fan blades on an integrally bladed rotor (IBR) rubbing against the engine casing. The blades were in the third stage of the F135’s turbine section. While some level of rubbing is acceptable, this particular engine was operating beyond tolerances.

Former Pentagon official Pierre Sprey, and frequent F-35 critic, said that micro-cracks developed in the blades before the rubbing led to a catastrophic failure.

“If the micro-cracks came first and very slightly elongated the fan blades, the rubbing plus heating that led to the ultimate disintegration would have been a consequence of far-to-early fatigue micro-cracks–and that means a redesign and requalification of the third stage,” he told USNI News.

The Pentagon said on Tuesday the F-35 will not make an appearance debut at the Farnborough airshow outside of London this week.

“I can confirm that 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,” Kirby said in a Tuesday afternoon press conference.
“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 fleet-wide grounding of the F-35 raises questions about the wisdom 2011 cancellation of a backup engine for the aircraft called the General Electric F136.

The original idea was that Pratt & Whitney and General Electric would complete to supply engines keeping prices down and production quality high, however then-secretary of defense Robert Gates cancelled that effort due to cost. Having two engines would also mean that the entire fleet could not be grounded due to an engine malfunction.

  • 2IDSGT

    Really Dave? Did you seriously just make f*cking Sprey your authority on the root cause? You need to save that kind of dip$hittery for your ‘Daily Beast’ articles.

  • CharleyA

    IDK, Sprey has some well connected friends, but I don’t know where he’s getting his info. Perhaps there’s something to it, maybe not. Time will tell.

  • Ctrot

    For the love of…. Sprey is NOT AN ENGINEER. He is not an expert on anything other than self promotion.

    Why do you IDIOTS keep listening to that IDIOT?

    Oh wait, I think I just answered my own question. Carry on.

  • CaptainParker

    What good is a plane whose range and mission are restricted because you can’t be certain it won’t catch fire in flight? This plane is the most expensive dog in our history of military procurement. How many generals and admirals have been bought off so this plane can make the vendors rich and guarantee the hacks in Congress bragging rights that they brought defense jobs to their districts? How about taking a look at the privately funded and designed Scorpion fighter which was demonstrated at the British air show? It only costs $20 million a pop AND IT WORKS!

    • Secundius

      @ CaptainParker.

      The Scorpion, is not a fighter, It’s COIN or COunter INsurgency, Light-Attack Aircraft. With similar performance characteristics to the Cessna OA-37B Dragonfly.

  • muzzleloader

    I guess for now this dog is cleared for straight and level flight. LoL