Okay, back to basic natural science;
To initiate visible oxydizing combustion (flame or explosion) in an atmosphere you must have 18 to 20 per cent oxygen.
In any fuel tank with any liquid fuel there will be virtually no oxygen.
TWA had 1000lbs in the tank.
Sparks and arcs in a fuel rich atmosphere without enough oxygen don't cause flame or explosion.
That's the single biggest reason why engineers in the 40's and 50's knew they didn't have to enclose the wiring in fuel tanks in conduit or any other sealed vessel.
Engineers today are learning from instructors and teachers in their third and fourth (and if you count my niece, fifth) generation of instructors and teachers who learned what they know from instructors and teachers who haven't practiced what they're teaching.
When I got my credentials in the state of Florida, two years post graduate experience was required before you could be certified in any of the aeronautical or electronic disciplines.
Now we have 22 year old kids with four year degrees trying to tell technicians with 30+ years of airline experience how to put things together and they have to invent new words to explain their machinations because they don't know the vocabulary that's been in place for the last 60+ years.
I don't like flying any more and I'm liking teaching even less.
