One episode of the BBC series "Engineering Giants" featured a BA 747 undergoing a multi-week "D check". Here the inside of a fuel tank was surprisingly clean and dry (to me):

since elsewhere I've read of technicians having to wear respirators and protective overalls. Presumably the lighter fuel fractions can be driven out with forced ventillation, but is a specific cleaning process required to remove less volatile compounds?

  • $\begingroup$ Do you mean by cleaning an aircraft fuel tank or any vehicle fuel tank? $\endgroup$
    – Super
    Mar 18, 2018 at 19:19
  • $\begingroup$ @FallenUser Aircraft tanks, although perhaps the approach is the same for all tanks? (naively I'd assume that regarding sticky non-volatile compounds petrol < aviation fuel < diesel ?) $\endgroup$ Mar 18, 2018 at 20:48

1 Answer 1


FAA design regulations require that the aircraft be equipped with fuel system drain valves that allow the entire fuel system to be drained.

"Fuel System Drains - Aircraft fuel systems must be fitted with at least one drain to allow safe drainage of the entire fuel system with the airplane in its normal ground attitude."

According to a maintenance person: "The residual is vacuumed or absorbed and the negative ventilation is applied. You can make entry almost immediately, though air monitoring is constant. We keep air moving through the tank anytime there is someone in the tank. "

Doesn't clearly answer the question, but this article discusses the procedures for personal protection while entering aircraft fuel tanks.


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