Fortyodd2
Yes I did read your post on all the warnings before running out out of fuel - very useful. And I don't believe for one minute this would have all occurred and the engines then stopped. As I said, given the heavy impact, I am very impressed with the integrity of the 135's fuel tank arrangement - and structure generally. However whatever caused this accident, it will be something extremely unlikely to happen. Maybe there was a failure of part of the low fuel warning system, or a fuel pump? I recall the Dyfed 109 crashing several years ago following a failed fuel pump, though that was from mis-management of the pump failure and cross-feed use when low on fuel. Fortunately that was also with forward speed and in daylight, and onto grass as far as I recall. However had it happened at night in a high hover over a built up area, I suspect it might not have looked too dissimilar to this.
Catastrophic main transmission failure is obviously possible, though one might have thought it would either freewheel and be possible to autorotate, or the abrupt deceleration would tear the MGB out, as with the Ian Shoebridge AS355 accident near Thruxton many years ago. TR drive failure would presumably have been more likely to result in the integrity of the aircraft being maintained until impact.
Finally I'm sure the roofing felt black roof would have looked very like an empty car park at night, so a 'least bad' place perhaps to attempt an auto to. Certainly sounds as though Dave Traill was a very skilled pilot and did his best to mitigate a desperate situation.