The F-35 program continues to work through a litany of problems, but this one is almost laughable. According to the USAF, the troubled fighter cannot use gas from standard green colored USAF fuel trucks if it has been sitting in the sun. Considering that these jets will most likely find themselves operating in the desert or in somewhere in the scorching Pacific, this is a big problem.

Sadly, the answer for the F-35's fuel finicky conundrum, one of many heat related issues with the jets since their testing began, is being addressed outside of the F-35 aircraft itself, in the form of repainting standard USAF fuel trucks with bright white solar reflective paint.

Clearly it is not tactical in any way to be driving a giant white potential fuel-bomb around a battle zone. This is especially true considering that the F-35B variant is supposed to operate 'forward' from austere fields. Still, the solar reflective paint job, that costs around four grand for each truck, seems to be less expensive than fixing the issue on the jet itself, as there is no word of that happening.

Senior Airman Jacob Hartman, of the 56th Logistics Readiness Squadron (LRS), a fuels distribution operator at Luke AFB, describes the situation:



"We painted the refuelers white to reduce the temperature of fuel being delivered to the F-35 Lightning II joint strike fighter... The F-35 has a fuel temperature threshold and may not function properly if the fuel temperature is too high, so after collaborating with other bases and receiving waiver approval from (the Air Education Training Command), we painted the tanks white."

Chief Master Sgt. Ralph Resch, the 56th LRS fuels manager added:

"We are taking proactive measures to mitigate any possible aircraft shutdowns due to high fuel temperatures in the future. It ensures the F-35 is able to meet its sortie requirements... This is the short-term goal to cool the fuel for the F-35; however, the long-term fix is to have parking shades for the refuelers."

Luke AFB is not the first base to run into this issue, with Edwards AFB discovering the problem and initiating the fuel truck repaint solution some time ago. The USAF has some hope that the reflective paint process can be applied to a similar green color as the standard issue refueling trucks used by the USAF. A test will soon occur with a white truck and a green truck, with both being painted with a special solar reflective coating, to see if the green truck plus the reflective coating will keep the F-35's life-force cool enough under the sun for the jet not to have to shut down immediately after start-up due to heating issues.


What is most telling about this strange story is that the USAF thinks a long-term solution to the F-35's warm fuel problem is to park their fuel trucks under purpose-built shade structures. Yet isn't fixing the aircraft's low fuel temperature 'threshold' issue itself more of an honest, robust and logical solution? Like so many things F-35, maybe the operating margins are just too thin for an affordable aircraft-based fix to be plausible.

The F-35 channels its strong thermal loads, accumulated by the powerful avionics and sub-systems on-board, as well as the engine, into its fuel. So really, the fuel works as a giant heat sink. If the fuel is already warm upon start-up, there is less capacity to exchange the heat from their aircraft's simmering systems. Therefore the jet must shut down or risk overheating. A clever design that most likely lightens up the jet and leaves extra room for weapons and fuel, but one that may have very little room for adaptation.

The simple fact that the F-35 is one finicky eater even after many years of development and costly design changes, along with the reality that bright white fuel trucks may become standard issue on F-35 flightlines, are just more sorry reminders of how this supposedly super-capable fighter will come with a long list of limitations and operational caveats, along with its one and a half trillion dollar bill.

Source: USAF



Tyler Rogoway is a defense journalist and photographer who maintains the website Foxtrot Alpha for You can reach Tyler with story ideas or direct comments regarding this or any other defense topic via the email address