In the early 80's, flying training in Jet Provosts, jet pipe fires weren't unusual due to the aircraft having an engine in the middle and a long tailpipe to fet the hot gas out the back. The engineers were required to check the jet pipe after shutdown. One day the didn't and after the last flight of the day they towed one into the hangar with a tailpipe fire still burning!
The definition of chaos was quite clear that day!