I understand the need for SOPs about fuelling and APU use, loading pax etc
All flammable fuel should be treated with respect and procedures but....
I have had a few experiences with aircraft fuel and sparks or flames that I may share . I am not recommending disobeying any SOPS but sometimes other peoples experiences can paint a different picture or perspective.
Disclaimer :- we are talking about aircraft that only ever use Jet A or A1
As youth worked in the local fuel farm, (Storage tanks) every day the Jet A1 was tested for S.G and flash point. Flash point is an excellent indicator for quality of product ie if the flash point is lower more wide cut fuel in the mix.
From memory the min temperature that Jet A1 was allowed to flash was around 50 deg C. Flash point is lower than flame point which is the temp the fuel has to be to sustain fire.
The flash point test is a small amount of fuel is heated and temp monitored with an ignition source above, when the fuel vapour "flashes" the temp is recorded. In my time never saw anything below 80 Deg.
Long and the short Jet A1 needs to be fairly hot to sustain a flame if its in a puddle but an atomised spray is a different matter.
As above in my halcyon days I was slim enough to easily fit inside Boeing aircraft fuel tanks a fact the other members of my crew relished. ( An attribute I quickly changed with beer)
I quickly gained many hours of fuel tank experience and trouble shooting.
A defect that needed rectification required the removal of a component and its mounting bolts were rounded and seized. Normal spanners would not do the job.
The tank I was in was still freshly opened, fuel puddled everywhere, myself with breathing apparatus on. There was no way a high speed cutter would be deployed as the shower of sparks was to scary to contemplate.
So the mark 1 shiny sharp cold chisel and hammer were deployed.
The head of the bolt was dispatched with ease and caught in a plastic bag tapped into position but I did not notice this for my attention was fixed on the spark that flew off the bolt and sailed 4-5 feet across the tank to extinguish in a tiny puddle of fuel. I will admit it was unnerving.
Just a few experiences amongst many with jet fuel, some of which may explain why different airlines have different SOPs regarding operations when fuelling.
