There has been discussion about Harold and Maude seeing the plane on fire or hearing sputtering, and I agree, you almost always get "witnesses" that say that. In this case, I think there may be some truth to the matter. As mentioned previously, the plane clipped the power lines (and trees) before impacting the hill. This could have ruptured a fuel tank and the impacted electrical lines could have ignited it. From the insulators I can see in the photos, it looks like that there is 12KV service in that area, so the arcing could have been significant.
I also think that the "sputtering engines" may have been the sound of high voltage arcing, spring fuses melting, or the utility recloser in operation. The recloser is a type of automated circuit breaker that attempts to "re close" the circuit several times (usually three) after a fault, the theory being that most faults are temporary, so why keep the juice off. When this operation occurs into a hard fault like downed lines, it does indeed sound like very loud "sputtering".
Last edited by areobat; 15th Aug 2013 at 15:13.