Fuel-Dissolving Fuel Lines Ground F-35s


The grounding of the Air Force’s “operational” fleet of about 15 F-35s is being characterized as routine but as has become routine with glitches in the aircraft’s development it’s also likely to be expensive. It appears faulty materials in the avionics cooling system will have to be replaced and while that sounds simple, the likely solution will almost certainly be pricey. The aircraft uses fuel to cool the avionics and the insulated lines that circulate that fuel are breaking down. The airframes must be substantially disassembled to get at the cooling lines.DefenseNews says the problem is isolated to 13 USAF F-35s and two owned by Norway. All the aircraft are in the U.S. The issue is that as the lines crumble they can block the transfer lines and that can cause some really serious issues beyond overheating avionics.

“This could result in excessive negative pressures in the fuel tanks during flying operations orexcessive positive pressures during air or ground refueling,” said Air Force spokeswoman Ann Stefanek. “In either case, the under- or over-pressure could cause structural damage to the fuel tanks.” The Air Force didn’t say who made the fuel transfer lines and it doesn’t seem like the unnamed company will be fired.”There has been no discussion about changing doing business with them,” said Lockheed Martin spokesman Mike Rein. Apparently the company used materials for the fuel lines that were “not compatible” with the fuel. “The non-conforming material that was used is not compatible with fuel, causing degradation of the insulation and resulting in it falling off the tubing,” Lockheed Martin said in its statement.