If this is in response to my comment, I wasn't suggesting that a fuel tank had been ruptured but was simply puzzled by the flare up as the RFFS started spraying the wingtip. But there must have been some fuel source for the fire and I'd be surprised if it was anything other than fuel, and it had to come from somewhere. Does the fuel tank/system extend that far into the wing?
Maybe they sent a fuel bowser rather than the RFFS
