[Chode]

i think one sounds most likely

two wouldn't you hear odd engine noise

three it was bright flame and no real smoke like i'd expect from an oil fire

forth i don't even want to go there, but i hope not

[Lockbox]

Regarding two, also maybe smoke out tail pipe.

Agree on three, did not burn like an oil fire or a carbon fiber fire.

Just wonder how fuel traveled up stream?