The issue appears to have been with a supplier of coolant lines, which are installed in the wings of the jet. During a routine maintenance check, it was discovered that the insulation on the lines were in some cases decomposing, which left residue in the fuel itself, according to a release from the Norwegian government on the grounding.
The issue has been traced back to the insulated coolant tubes manufactured by one particular provider that have only been installed in the wing fuel tanks of the 15 aircraft — 10 from Hill Air Force Base, Utah, two US and two Norwegian F-35As at Luke AFB, Ariz., and one plane at Nellis AFB, Nev.
The problem was first discovered this summer during depot maintenance of an F-35A being prepared for initial operational capability, Lockheed Martin spokesman Mike Rein said.
After maintainers found three aircraft with crumbling coolant tubes, Lockheed conducted subsequent tests that “indicated it was possible for this crumbling insulation to become lodged in the siphon lines connecting wing and fuselage fuel tanks,” said US Air Force spokeswoman Ann Stefanek. “This could result in excessive negative pressures in the fuel tanks during flying operations or excessive positive pressures during air or ground refueling. In either case, the under- or over-pressure could cause structural damage to the fuel tanks.”
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The F-35 . . . So far –
• The U.S. DOD announced an agreement known as Blueprint for Affordability in July 2014, aimed at reducing the price of an F-35 to the equivalent of today’s 4th generation fighters by the end of the decade.
• The U.S. government stated the projected cost of an F-35 purchased in 2018 will be $85 million. That’s the equivalent of $75 million in FY 2012 dollars
. • In 2014, the U.S. DOD announced a more than $500 million reduction in concurrency costs over the first five production lot contracts.
• The Low rate initial production (LRIP) 8 contract reflects an average airframe unit cost approximately 3.5 percent lower than the LRIP 7 contract signed in 2013 and a 57 percent reduction since LRIP 1.
• LRIP 6 Aircraft Costs (not including engine): o 23 F-35As CTOL – $103 million/jet o 6 F-35B STOVL – $109 million/jet o 7 F-35C CV – $120 million/jet
• LRIP 7 Aircraft Costs (not including engine): o 24 F-35As CTOL – $98 million/jet o 7 F-35B STOVL – $104 million/jet o 4 F-35C CV – $116 million/jet
• LRIP 8 Aircraft Costs (not including engine): o 19 F-35As CTOL – $94.8 million/jet o 6 F-35B STOVL – $102.0 million/jet o 4 F-35C CV – $115.7 million/jet