Safety Flight: I mentioned the ELT going off. (The ARCC received a signal)
I missed the post that said David was @ 700' in the cruise.
I sincerely wish NOT to upset readers with the following "theory of events":
Please do not read further if you think it may offend you.
IF and a massive IF he lost it at this height and weighing in at approx 2.5 tonnes he would have free fallen @ 10m/s squared. It meant 50% terminal velocity in 3s. 99% terminal velocity in 6 seconds. I estimate a minimum impact speed of around 90m/s(200mph).
You state the u/c can cope with a vertical landing of around 6mph??? Is that correct?
For those who are not familiar, the wreckage compression stopped about 1 foot below the gearbox platform. That means the rest of the cabin area (approx 4 feet without extended u/c skids(?) was crushed. This is consistent in my mind with wreckage I have seen from several aircraft crashes and road traffic accidents I attended, where high speeds and hard stops have been involved.
Thus - this accident started long before the end. IF he was @ 700 feet en route to his base, he went from this to the pub roof stationary AND vertical without his engines or his rotors.
My theory (and I only post this because this is what readers are here for: theories. Don't lambast me because you think "what does he know". I don't! That is why it is a theory).
The cab was 1 mile from base @ cruise height and maybe 70-80kts (due to the proximity of his decent into base). Evidence shows him to have been airborne for 1:37hrs [Up 2045, lost contact: 2222]. He had uploaded 400Kg fuel. Take away his MLA of 95Kg gives us 305Kg useable for normal ops. At 3.3Kg/min fuel usage this gives us: 1:32hrs to MLA. I therefore surmise that he may have had a fuel caption illuminated on one or both engines (amber or red - can't remember).
2 eye witnesses have independently stated that they heard "mis firings" and "back firings" from the engine. I surmise that while comfortably weighing up the fuel scenario, he was suddenly hit by stall or surge on one engine. In both situations Nr will drop (albeit by a small amount) as T4 and Tq argue with each other and the remaining engine compensates for the lack of power output from the duff engine. While he initiates the correct actions to deselct the duff engine (and switches the controls for that engine - off), either then, or shortly thereafter, the remaining healthy engine flames out due to a fuel irregularity caused by low fuel.
In the meantime he has slowed somewhat below min speed (65kts) thus demanding more power to retain Nr in the governed range and he has noticed that the Nr is decaying fast. By the time he has fully lowered the lever to slug the Nr he has slowed further to look for a landing spot close by, the Nr is now down around his knees.
[There is an element in me that thinks that here we have a pilot who has always (except for his very early days of training) flown twins. He subconsciously may have thought that this could not be happening to him and as a result, delayed the onset of hard down collective.]
I also happen to think Hydraulics disengage @ 65bar and he loses control of the a/c allowing it to flip backwards if he was pulling back at the time and tumble vertically. I wait to see if the engine switches show one engine properly shut down and the other starved of fuel but swtiches still in the ON position.
Please feel free to savage this theory?