A Theory
So how about this for a scenario
Both transfer pumps off as can happen during police scenarios due to transit and hover.
You would normally be made aware of this by supply tank contents reducing with fuel still in the main tank. Next thing you get is the yellow fuel caption, the eventually the red low fuel caption. You would have to ignore all these inputs to let the supply tanks run dry and the engine flameout.
What about if the first indication you get is the reflow fuel caption. You know you haven't had the yellow caption, which you should have had and both supply tanks are indicating full. Logical conclusion maybe that the low fuel caption is spurious as the gauges have always been extremely accurate.
Then an engine fails. You still have supply tanks indicating full and 78kg in the main. Natural reaction over a city at night maybe - ok, no need to panic. I have rotor rpm and fuel. Remain cal get into single engine speed and make a decision about continuing to the heliport or going to the airport. 30 secs latter the second engine fails. You are very poorly placed.
What's interesting is that the AAIB report does not mention the yellow fuel caption coming on.
Also interesting is that the current problem with EC135 fuel probes, only highlighted after the accident, is indicated by the yellow fuel caption not coming on and the supply tanks over reading (sometime indicating full)
I'd also like to comment on the lack of autorotation theory. The final route of the aircraft was 180 out from its final resting orientation. It came over a high building attached to the rear of the pub.
What if autorotation was successfully entered albeit with rrpm on the low side. From 1000 at night over a city, there is very little time and few options to choose from. What if at the final stages you are faced with a large building. Crash into it of flare and use some collective. Survival instinct would be that you flare. You've now used our one shot of collective but you fall with no rrpm over the other side of the building.
So maybe this guy didn't just ignore all the warnings that he should have had and maybe he did get into autorotation. Maybe he was faced with a very confusing situation over a city at night.
Just trying to balance some of the very black and white and sometimesl informed views on here.
Fact
From the AAIB
Transfer pumps were off - they should not have been and this Pedro the supply tanks emptying
The yellow fuel caption coming is not mentioned.
From airbus helicopters
Current EC135 fuel probe issue
Yellow fuel caption may not come on
Supply tanks indications may over read.