It takes only one tiny spark to ignite petrol fumes as a Piper Aztec pilot found out to his cost on final approach to an airport in USA. A fuel line to the fuel flow indicator came adrift behind the instrument panel and sprayed raw fuel on the pilot’s feet and soaked the carpet
(Shiver) dammit, wish I hadn't read that. I had the same thing happen to me in an Aero Commander years ago whilst working for a delightful ga company, the owner of which tried to repair/install a fuel flow gauge without the required knowledge and no paperwork only for it to rupture in flight in IMC the next day. The amount of fuel that instantly cascaded down from behind the instrument panel and sloshed around the floor is still truly hard to believe, as was the struggle to fight off total incapacitation. Despite being covered in Avgas and suffering some pretty nasty chemical burns (particularly eyes) I still can't believe that there wasn't a fire and that I survived. I can only imagine that the volume of liquid fuel & lack of oxygen didn't support combustion from the 40 year old Sh!tty electrics that had a tendency to arc out at the best of times (did I say it was a delightful ga company), which were hastily switched off after a mayday call. (Shiver) dammit I wish I hadn't read that.