Ah TML, I guess the wet seasons started up there. Heat must be getting to you.
A spark will only ingite fuel vapour that is in direct contact with the ignition source. A closer inspection of the pic will show the wing severed outboard of the wing tanks, no fuel vapour from a sealed vessel.
When the A/C has come to rest the power lines would have already contacted earth and as any yr 10 physics student can tell you, there needs to be a gap between two differing voltages produce a spark.
I'm not suggesting that fuel wasn't an issue, but why are you trying to hang this guy for something which you do not have all the information. I pray that if there ever comes a day that I have to make a forced landing you're not on the investigation team!!!!!