(Update 2) How the F-35 Grounding Unfolded
(Source: Defense-Aerospace.com; published Sept 30, 2016)

By Giovanni de Briganti
PARIS --- Close scrutiny of the events surrounding the flight ban on 15 F-35A fighters belong to the US Air Force (13 aircraft) and the Royal Norwegian Air Force (2 aircraft) shows that the service took several weeks to realize the scope of the problem that eventually led to the Sept. 16 grounding of the aircraft.

In fact, the long and deliberate, 5-week process that led to the Sept 16 grounding shows no urgency, and that no special attention was given to the crumbling insulation issue for several weeks, which is surprising given the F-35’s troubles history and the symbolism attached to it achieving Initial Operational Capability.

The US Air Force and Lockheed Martin both say they have not finalized how the crumbling insulation can be removed from the fuel tanks, and the faulty parts replaced – there are 18 coolant lines in each aircraft – at least two major questions remain unclear.

-- Given that crumbling insulation was found in two Norwegian aircraft delivered on July 6 and July 27, it appears that the insulation crumbles in a matter of days. Yet several US Air Force aircraft delivered in 2015 flew for over seven months without any adverse effect. Was it simply a matter of luck that a fuel tank didn’t explode in flight?

-- The coolant lines with faulty insulation were provided by a new vendor being evaluated, yet Lockheed Martin installed them on 57 aircraft (15 delivered and 42 still on the final assembly line) without carrying out the most elementary quality controls.

The US Air Force official interviewed below said it was a Lockheed problem, and Lockheed Martin spokesman Michael J. Rein said in a Sept 26 e-mail that “This is all being researched at this time.”

Regarding the repairs, which are to be completed by December on the delivered aircraft, Rein said that “The final repairs are being evaluated. It will require cutting some holes in wings, but we have done this before. We also have access panels on the wings. The non-conforming insulation will be stripped and replaced with conforming insulation.

He added that “the timeline [of the repairs] isn't finalized yet and we do not have a cost estimate at this time.”

This is how events unfolded, according to US Air Force spokesman Capt. Mark A. Graff:

Official US Air Force position

On August 11, during depot modification work on an F-35A aircraft at Hill Air Force Base, Utah, a team of Air force and Lockheed Martin maintainers discovered that polyalphaolefin (PAO) tube insulation associated with the F-35A Lightning II Power Thermal Management System (PTMS) system was peeling away and crumbling from around the lines inside the fuel tanks.

A temporary pause in flying operations for the 15 affected aircraft - 13 U.S. Air Force and 2 Norwegian F-35As - was ordered on September 9, pending completion of a Time Compliance Technical Directive and inspections to assess the condition of the insulating material, including its size and location within the fuel tanks.

Those inspections concluded on Sept. 15, with the assessment that all suspected aircraft would be affected by the issue. Thus, the temporary pause in flying operations remains in place for the 13 affected U.S. Air Force aircraft until repairs are completed, which are scheduled to be completed by the end of the year.

The F-35A was declared combat ready on August 2 and that remains the case.

Repairs to the insulation will not detract from the F-35A's stealth capabilities, or any other attributes unique to the Air Force's newest fifth generation fighter aircraft.

Additional details

Another US Air Force official provided additional information during a Sept. 28 telephone interview, including:

1. The crumbling insulation was discovered by maintainers from both the Air Force and prime contractor Lockheed Martin who were modifying an F-35A’s fuel system to prepare it for Initial Operational Capability.

2. Initially, engineers thought the insulation problem was limited to a single aircraft, but “weeks later” found it on a second one, which sparked an inspection of more aircraft.

3. The same insulation problem was found in 10 aircraft at Hill AFB and another 2 at Luke AFB and one at Nellis AFB, in addition to the 2 Norwegian aircraft also stationed at Luke.

4. At this time “there was still no urgency” as engineers didn’t think the crumbling insulation was serious enough to risk causing the loss of an engine.

5. Sometime later, in early September, simulations determined the debris could clog fuel transfer lines and potentially under- or over-pressurize a fuel tank, resulting in structural damage to the tank. Inspections were then ordered for all aircraft at Hill AFB.

6. It was then determined the affected aircraft were unfit to fly, and they were grounded. The grounding, and indeed the problem itself, were acknowledged by the Air Force in a statement on Sept. 16, after Bloomberg News first reported the grounding.

7. The affected aircraft are all LRIP Lot 7 and Lot 8 aircraft that were delivered in 2015 and 2016. On average, they would have flown less than 250 hours each on an annual basis, but no individual flight hour count was available per aircraft.

8. Today, five IOC aircraft are still flying as they were not affected by this issue. The IOC squadron, however, can if necessary use any of the 85 other F-35As delivered so far, most of which have been inspected and cleared, the Air Force official said.

9. The fuel over-pressurization mod required for aircraft to be fully combat ready (full envelope) is incorporated into production starting with Lot 9 aircraft. There are still five Lot 8 aircraft to deliver to Hill which will need this modification prior to being fully combat capable.

Looking to the future, the Air Force notes the following:

10. The next combat coded jet, tail 102, was scheduled for delivery this month. That aircraft is awaiting removal of defective insulation. We do not have any [information] on when aircraft delivery will carry on.

-- Right now, ACC is not receiving any new combat coded aircraft until 1) delivered aircraft are repaired and 2) future deliveries of combat coded aircraft are free of PAO tube insulation defects.

-- We know that repairs will conclude by the end of the year. We do not at this time have an estimate of when deliveries will resume.

(end of update 2)

(Updated) F-35 Insulation Failure: Status and Questions
(Source: compiled by Defense-Aerospace.com; posted Sept 22, 2016)
PARIS --- A week after the US Air Force grounded 15 F-35A fighters, very little additional information has been released about the circumstances and background of this, the latest incident in the troubled program’s long history of technical problems.

Characteristically, the message from US Air Force leaders was to shrug off as inevitable, if not desirable, the technical faults that are being discovered on delivered aircraft. Lt Gen Christopher Bogdan, F-35 Program Executive Officer, said. “The mark of a good program is not that you don’t have any problems, but that you find things early, you fix them, you make the airplane better, you make the weapons system better, and you move on,” he said.

Left unsaid is that 2016 marks the F-35’s fifteenth year of development, which hardly qualifies as “early,” but that is just one more sign showing how far the program has become detached from reality.

“Now is the time to find this and fix them,” Bogdan added. If such problems had not been found today, “but three or four years from now, we [would have had] hundreds of airplanes out there affected.”

Also upbeat, Major General Morten Klever, director of the Norwegian F-35 Program Office, noted Sept 16 that “What is positive in this is that this shows that the maintenance routines in place for the aircraft have worked…. We expect this to be resolved by the time we receive the next aircraft currently in production,” due in early 2017.

Only pilots, maintainers qualified to discuss F-35

Possibly embarrassed by the fact that the grounding happened just six weeks after the Air Force, with much fanfare, declared the aircraft’s Initial Operational Capability (IOC), Air Force generals have made extraordinary statements about criticism of the troubled program.

“I’m hopeful that …. we all take the opportunity to form opinions on this airplane from experts, and the only experts in the F-35 business are those that fix, maintain and fly the F-35 on a day-to-day basis,” Brig. Gen. Scott Pleus, director of the Air Force F-35 Integration Office, told the Air Force Association Air, Space and Cyber conference in National Harbor, Md. “If you are forming your opinions by somebody who has not fixed or flown the airplane, I would tell you you’re wrong.”

In a sweeping indictment of program skeptics, Pleus added that “Critics are wrong, and I’m here to tell you that this aircraft is performing very well and getting better each and every day.” As usual, no data was provided to back up this claim, which is routinely disproved by events.

This unfocused attack on the credibility of “critics” of the program was also taken up by Gen. Herbert “Hawk” Carlisle, chief of Air Combat Command, who complained there are people “who will make comments, but will never actually have to do anything.”

He and Pleus probably overlooked the fact that, if the F-35 was on schedule, on budget and living up to its hyperbolic billing, critics wouldn’t have a leg to stand on and could be dismissed off-hand. Given the program’s real situation, however, it is remarks such as these that show the program, and senior Pentagon leaders involved in the program, require adult supervision.

We have selected below a series of excerpts from a range of media outlets in an attempt to clarify the underlying issues and the way forward. Links to all sources are provided at bottom.

Remarkably, the US Air Force, which throughout August issued many press releases and statements celebrating the F-35A’s Initial Operating Capability, has not issued a single one about this latest grounding. The only official comments so far have been made by officials speaking at the AFA conference.

Norway provides additional details (Added Sept. 24)

-- The two Norwegian aircraft were delivered to Luke air force base on July 6 and July 27.

-- They had flown 36 and 21 hours respectively by the time they were grounded.

-- Asked how quality controls could have missed the sub-standard insulation which caused the grounding, the spokesman for the Royal Norwegian Air Force's F-35 program said:
"That is what the ongoing review seeks to uncover. There will always be a risk of mistakes in a program this complex, which is why we need to learn from it, and ensure we reduce the risk of this happening again even further.
It is not acceptable that a faulty part escapes quality control measures and is installed on an aircraft."

-- There is an alternate provider for the faulty part, "though the provider of these parts has since taken corrective action, and now delivers parts in accordance with stated requirements," the spokesman added.

What we know about the fuel line incident

-- "peeling and crumbling" insulation was discovered inside avionics cooling lines in some A-model fuel tanks, which are used as heat sinks.

-- Lockheed says the “non-conforming insulation was found on coolant tubing carrying Poly-Alpha-Olefin (PAO) throughout the jet’s wings.”

-- The insulation deteriorated when it met fuel and crumbled, clogging the vent between the wing tank and fuselage tank, but would not affect the engine’s performance, Lt Gen Chris Bogdan said at the annual Air Force Association conference Tuesday.

-- The problem was discovered by the Air Force during depot maintenance but had not been spotted by quality assurance controls.

-- The faulty insulation was supplied by a secondary vendor who was being integrated into the F-35 supply chain. The two other versions, -B and -C, are not affected.

-- Major General Morten Klever, the director of the Norwegian F-35 Program Office, described the problem as being “caused by a supplier using improper materials and improper sealing techniques for these specific parts.”

-- The Norwegian statement issued Sept 16 adds that “the insulation issue was discovered during routine depot maintenance of a US aircraft, with subsequent inspections confirming issues with other aircraft fitted with cooling lines from the same provider.”

-- The US Air Force has not issued a statement about the incident or the subsequent grounding, and neither is mentioned on its websites.

-- Neither Lockheed not the USAF have identified the supplier at fault, save to say it was a second source brought on last year as an insurance measure for the production ramp up, Bogdan said.

Which aircraft are affected

-- 13 US Air Force and two Norwegian F-35As at Luke Air Force Base have been grounded. The Norwegian aircraft are the third and fourth, and were delivered this summer.

-- 42 aircraft on the Lockheed final assembly line at Fort Worth have also been fitted with the same sub-standard insulation, which must be replaced. Most of these aircraft are intended for the US Air Force, but also included are:
* the first two F-35As for Israel, which were due to be delivered in December, and several more Israeli aircraft;
* three more Norwegian F-35As, due for delivery in early 2017;
* an unknown number for the Italian air force and the Japan Air Self-Defense Force.

The fix

-- Bogdan said the program is assessing the risks associated with flying the aircraft before the fix is made. "We're doing a risk assessment right now to see if any or all of them, based on the damage we've seen from inspections, could get back in the air while they're waiting to get fixed," he said. "We should have the assessment done in the next week or so."

-- The US Air Force is currently working to develop a fix for the problem, and ACC chief Hawk Carlisle said a solution has not yet been identified.
-- Lockheed is expected to test a fix for the problem on a ground-test aircraft next week, JPO chief Lt Gen Chris Bogdan told reporters.

-- Pending this test, Lockheed has assembled eight teams to begin repairing the fielded aircraft in the next two weeks. The Air Force expects repairs will take until December to complete.

-- “Our first priority is the 15 airplanes in the field and then we will work our way back to resolving the 42 airplanes on the production line,” Bogdan said. “We will spend most of October and November ‘modding’ those airplanes and getting them back into a flyable condition and then we will work on the production airplanes.”

-- The JPO, Lockheed Martin, the Air Force Life Cycle Management Center and the Naval Air Systems Command “have come up with an engineering solution in which we will go in by cutting holes in the wings—and there are access panels we can go through also—and remove that insulation and FOD [foreign object damage)] and close the airplane up and allow it to get back into flight,” Bogdan said.

Cost and payment

"To Lockheed's credit, at the highest levels of the corporation they have committed to doing the right thing and the definition of doing the right thing is they will pay for all of the engineering and manufacturing and all of the modification for all 52 airplanes," Bogdan said. "I do not know how much [the cost] is. They've made that commitment to me."

Unanswered questions

Whatever the details, the basic fact is that Lockheed was evaluating a prospective new supplier, but did not test its product before installing it on 57 production aircraft. How could this happen?

This is an extraordinary quality control failure, and all the more so that the company should have made a major effort to prevent any more incidents than are inevitable in an aircraft that has racked up an inordinate number of failures.

Furthermore, the Air Force said it had carried out multiple checks and inspections in the lead-up to declaring the aircraft’s IOC on August 2, so not finding this crumbling insulation points to less than perfect controls on the USAF side, as well.

Given the F-35 program’s record of transparency, it is natural to wonder whether the truth is not being massaged for public consumption. Significant questions remain unanswered:

-- when was the problem first identified?
-- when were the grounded aircraft delivered?
-- how many hours had they flown before the crumbling insulation was found?
-- did the USAF declare IOC before or after this problem was first identified?

The following reports were used to compile our overview:

U.S. Air Force Defends F-35A, Readies Fix for Grounded Jets
AIN Online, September 21, 2016,

AFA 2016: Pentagon expects F-35 coolant line fix in weeks
IHS Jane's Defence Weekly, September 21, 2016

US Air Force finds F-35 fuel line fix
Flightglobal, September 21, 2016

Air Force to Begin More Repairs on Grounded F-35s
DoD Buzz, September 20, 2016

F-35 JPO assessing risk of flying grounded jets before they're fixed
Inside Defense, September 20, 2016 |

Grounded F-35As may not fly for months
Inside Defense, September 20, 2016 |

Faulty Cooling Lines Identified on Two Norwegian F-35s
Norway Ministry of Defence, Sept 16, 2016

Temporary Suspension of Flight Operations Announced for A Limited Number of F-35A Aircraft
Lockheed Martin F-35.com; Sept 16, 2016

Story history
-- Sept. 24: Added additional information provided by the Royal Norwegian Air Force.


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