Air Force: Grounded F-35s return to air, parts supplier responsible for problem

Tuesday , November 29, 2016 - 5:30 AM1 comment

MITCH SHAW, Standard-Examiner Staff

HILL AIR FORCE BASE — The Air Force says an unnamed parts supplier is responsible for the fuel tank problem that grounded 10 of Hill Air Force Base’s F-35s earlier this year.  

Jet manufacturer Lockheed Martin and the Air Force recently announced maintenance teams finished repairs on all 13 operational F-35As that were grounded in September. The grounding came after crews at Hill discovered peeling and crumbling of the avionic cooling line insulation inside one of the F-35’s fuel tanks.

An investigation launched after the problem was discovered found eight other jets had the problem. The Air Force eventually grounded all 13 operational Lightning IIs that had the same cooling lines. A total of 57 F-35s were impacted by the problem, 42 of which were still in production. Ten of Hill’s 15 combat-ready jets were restricted from any flying operations.

A pair of Hill’s grounded jets returned to flight Oct. 28, with three more following on Nov. 4.

In a statement, Air Force Captain Mark Graff said a “non-compliant” insulation material was used inside the F-35s’ cooling line tubes, which resulted in insulation debris being released into the fuel tanks. Graff said one of the jets’ many sub-contractors installed the material.

“It is important to note that this is not an F-35 design flaw,” the statement says. “But rather a case of a supplier using improper material and improper sealing techniques for a part of the aircraft.”

Neither the Air Force nor Lockheed Martin has identified the supplier.

The Air Force said debris created by the faulty material and installation had the potential to create pressure problems that could cause structural damage to the jet’s fuel tank. Graff said the flying suspension was initiated “out of an abundance of caution, because the safety of our pilots is our number one priority.”

The repairs, which were conducted at Hill, included removing fuel and paneling from the jet and cutting holes in the aircraft skin to access the fuel tank. The faulty line coating was removed, and screens were installed to prevent debris from entering the system.

Graff said the F-35’s performance would not be impacted by the maintenance repairs.

“Identifying and addressing issues and improving the capabilities of this unique aircraft is a basic component of how we field effective systems,” he said.

In a separate news release, Col. Jason Rueschhoff — commander of Hill’s 388th Operations Group — said base pilots were sent to Luke, Eglin and Nellis Air Force bases to maintain flight proficiency while the grounding was in effect.

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