[woofa.express]

Y Blockhead (post 6 ) is correct.

Please let me contribute here.


Static electricity. I know of a helicopter refuelling fire when the hose was passed across the bubble. Two blokes badly burned, helicopter destroyed.
A second in 1979. Refuelling from drums to bulk truck tank. again in passing fuel hose. 92 drums exploded and one went through the back wall of an adjacent hangar. Aeroplanes pulled out. Very fortunately a local volunteer fireman was a part owner and had a key to open up. Don't park aeroplanes in hanger with breaks on, you could possibly loose them.
Proper aeroplane fuel delivery hoses have a fine copper wire running the length and earthed at both ends. Plus a wire and clip from nozzle to attach to aeroplane, Plus an earth wire earthed to attach to aeroplane. I reckon it's okay to skip this one provided you are satisfied the fuel hose is approved, or earthed.
Ensure the nozzle / earth is attached prior to opening fuel cap. If no earth wire ensure the nozzle handle touches aeroplane prior to opening the cap and ensure the nozzle is touching fuel tank whilst fuel is flowing.
I had an incident once where static formed when a camloc fitting in the delivery was synthetic thus insulated. Fortunately I felt electricity through my body. Used jumper leads for the remainder of day to earth drum to aeroplane. I also saw pictures of a auto fuel station destroyed when a bloke held his plastic containers off the ground and filled them with fuel.

It's easy to avoid but consequences can be severe if you don't.