Lockheed Tries to Deflect F-35C Tailhook Concerns
 
(Source: Defense-Aerospace.com; published Jan. 19, 2012)
 
 

Problems with the F-35C’s fully retractable tailhook are far more serious than Lockheed claims, and may even require a re-design of the rear airframe. (JSF PEO photo)
PARIS --- Having waited a month for the dust generated by the Pentagon’s Quick Look Report into the F-35 program to settle, Lockheed-Martin’s celebrated Tom Burbage was back in action this week, trying to downplay the seriousness of the problems with the F-35C’s tail hook.

During trials at Lakehurst, N.J., the F-35C’s tailhook failed to catch the arrester wires on the runway on all eight occasions this was attempted. Had this happened on an aircraft carrier, the airplane would have had to abort the landing and attempt to take-off again, or gone overboard. The QLR considers this “a significant issue.”

Yet, in a Jan. 18 story largely based on Burbage’s statements, Navy Times reports that “Efforts to fix the problem are well underway,” and quotes the Lockheed executive as saying that:

“The good news is that it’s fairly straight forward and isolated to the hook itself,” said Tom Burbage, Lockheed program manager for the F-35 program. “It doesn’t have secondary effects going into the rest of the airplane.”

and that:

Moreover, the rest of the design of the tailhook system, which include the doors and bay that conceal the device and other ancillary hardware, is sound, Burbage said.

Both of these statements are demonstrably false.

Contrary to what Burbage says, the problem is not isolated to the hook itself, as the QLR report identifies not one but “three major AHS design issues:” (1) the location of the tailhook on the airframe; (2) the tailhook design, and (3) ineffective performance of the tailhook’s hold-down damper, located on the airframe. (See page 11 and Annexes A9 to A12—Ed.)

By mentioning only the “tailhook itself” while ignoring the major design issues raised by its location on the airframe, Burbage gives a seriously misleading picture – unless, of course, he knows something that the report’s authors did not.

The real issue is that, if the tailhook cannot catch the arrester wire because it is located too close to the main landing gear, then the entire rear airframe will have to be redesigned to relocate the hook’s attachment point. This is likely to be highly complex.

The tailhook must be completely retracted to reduce the aircraft’s radar signature, and because it has to cope with the very high forces involved in arresting in only a few feet a 35,000-lb. aircraft moving at over 100kts, there are only very few places where it can be attached to the airframe without disemboweling the aircraft at each landing.

Recognizing the complexity of this problem, the QLR’s report’s authors say “the AHS is considered an area of major consequence” and add that “this issue represents a major concurrency risk which would have a significant retrofit impact to LRIP aircraft already delivered…(and)….in many respects, invalidate previously obtained developmental test and evaluation data.”

Their conclusion: “major concurrency risk – significant redesign risk and options are unknown at this time.”

Not quite the same as Burbage’s claim that this “straightforward” issue is “limited to the hook itself,” and that the “rest of the tailhook system’s design is “sound.”

Lockheed was also economical with the truth in a Jan. 12 press release proudly claiming that “F-35 Program Exceeds 2011 Flight Test Goals.” The release contained this remarkably upbeat statement:

"These achievements speak to the rapid maturation of the F-35 program and to our team's commitment to performing with excellence," said J.D. McFarlan, vice president of F-35 Test and Verification. "We will now turn towards 2012, expanding the flight envelope as we continue to demonstrate the F-35's excellent flight characteristics for all three variants."

Well, Lockheed may indeed have exceeded goals as to the number of test flights, but as a conveniently-leaked report by the Pentagon’s Director of Operational Test and Evaluation (DOT&E) makes clear, F-35 flight tests last year exposed many serious problems and shortfalls.

Regarding the tail hook issue, the report states “The tail-hook point is undergoing a redesign and the hold-down damper mechanism requires modifications to enable successful arrestments on the carrier. Resolution of these deficiencies is needed for testing to support F-35C ship trials in late 2013.”

The report also found numerous other problem issues. Here is a selection:

-- “Measurements of progress based on test points accomplished indicate mixed results for flight sciences of the three variant”
-- “Very limited mission systems software flight testing took place in 2011.”
-- “significant work and flight tests remain to verify and incorporate modifications
to STOVL aircraft required to correct known STOVL deficiencies and prepare the system for operational use.”
-- “current reliability and maintainability data indicate more attention is needed in these
areas to achieve an operationally suitable system.”
-- “live fire tests and analyses showed the fuel tank inerting system is incapable of providing protection from threat-induced fuel tank explosions”
-- “structural loads on the vertical tail fin of the F-35A aircraft…are higher than predicted and may require modifications to the tail or further changes to the flight control software to reduce these effects.”
-- Testers “found that fuel migrated back into the aircraft” in both the F-35A and F-35B variants, which “has the potential to create an unsafe condition.”
-- The horizontal tail “sustained heat damage at the inboard trailing edge area” in an F-35A after its afterburner was used for a long time on a flight test mission. “The damage consisted of blistering of the surface and missing pieces of the trailing edge.” Similar damage was found on an F-35B.


Click here for the DOT&E report’s 13-page section on the F-35, from which the above quotes are taken.

This is not quite as rosy as picture as Burbage and his Lockheed colleagues would have us believe.

Having a manufacturer defend its products is not, per se, objectionable, and Lockheed has so far done a decent job in catching up some of the delay in the flight test program.

What is objectionable, however, is the company’s very loose grasp on the truth, and its willingness to play fast and loose with the facts.

To date, two of Lockheed’s long-standing claims regarding the F-35 program have been proven to be catastrophically wrong:

-- its stubborn insistence that the aircraft would cost about $65 million apiece has finally been put to rest, and the unit cost of the aircraft (in LRIP Lot 5) has now risen to over $159 million – without engines.


-- its repeated claims that little flight-testing was necessary, because it was able to detect any flaws and issues through simulation, has also been conveniently dropped, as flight testing has brought up one serious issue after another.

It is stunning that, a decade after the Joint Strike Fighter program first began encountering serious problems, Lockheed has still not woken up to the fact that manipulating the truth makes it an easy target for its critics, and does absolutely nothing for its credibility.

-ends-

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