AAIB (Air Accident Investigation Branch of Department of Transport) have published a Special Bulletin.
No causal found so far.
Following list is quoted extracts from the report with comment and bolding.
- “At 2218 hrs, the pilot requested clearance from ATC [Air Traffic Control] to re-enter the Glasgow Control Zone and return to GCH [not known, assumed heliport]; this was approved. No further radio transmissions from the pilot were received.”
- “Radar contact with the helicopter was lost at 2222 hrs.”
- Weather was not exceptional.
- “Preliminary examination showed that all main rotor blades were attached at the time of the impact but that neither the main rotor nor the fenestron tail rotor were rotating.”, which supports eye witness accounts.
- “Once removed from the building, approximately 95 litres of fuel were drained from the fuel tank system.”
- “Initial assessment provided no evidence of major mechanical disruption of either engine and indicated that the main rotor gearbox was capable of providing drive from the No 2 engine power turbine to the main rotor and to the fenestron drive shaft.” and crash damage prevented a similar check for engine 1.
Investigation continues
- “some systems record fault codes, as they occur, in memory that is not crash-protected. Those, and systems that can record camera images and audio, will be examined and analysed.”
- “Radar data covering the helicopter flight has been recovered. That and radio communications are also being analysed, and closed-circuit television recordings will be reviewed”
Special Bulletin S9/2013 Published – EC135 T2+ on 29 November 2013, Glasgow
Any errors or contradictions are mine, the above linked document is master.
I have seen no report on the post-mortem on the pilot, which is likely to be confidential. All we need to know is whether there was sudden death prior to the crash.
Since I reported on the accident, also reporting on the investigation is apt.
Post by co-mod
Tallbloke's Talkshop 
Suicide? Engine capable of driving rotors, but not turning?
Its all very odd. Even if both engines shut down or failed the main rotor should be capable of autorotation. Eurocopters of this type have some history of rotorhead problems, failure of that could cause a catastrophic seizure. See http://www.ebearing.com/news2008/032601.htm
The pilot was a very experienced ex RAF helicopter pilot who was apparently well thought of and engaged to be married. In any case suicide by helicopter seems rather unlikely.
I’d not considered that Brian.
Doesn’t fit any of my knowledge or experience.
That are witness reports of abnormal noise. Given no obvious mechanical derangement has been found this shifts the likelihood to engine power loss.
It was dark, humid, ground level dewpoint close to freezing, shouldn’t have been a problem for a very experienced pilot. A question is more whether total power loss is easy to handle. I have in mind most accidents involve at least double faults where here we have darkness as a severe additional problem.
I’m also reminded of the AAIB report on the type where a systems fault led a pilot to think the engines had failed but this was daylight during level flight. The Glasgow case presumably was during early approach.
“Summary: 2007
The pilot and his passenger were returning to the UK from Europe. Whilst passing through the Stansted control zone, the helicopter had an event during which the auto trim in the Automatic Flight System disengaged and the helicopter pitched nose down. The pilot, believing he had a double engine failure, entered autorotation. During the landing flare the tail of the helicopter struck the ground first, severing the fenestron drive. The helicopter subsequently rolled on to its side and was extensively damaged. The occupants escaped without injuries.”
http://www.aaib.gov.uk/publications/bulletins/september_2008/eurocopter_ec135_t2__g_iwrc.cfm
Also observe this accident involving a police EC135 out of Glasgow but this time a T1.
In this case a systems failure combined with bad weather at night led to a forced landing with injury.
Also note, reminding readers this is a 2003 report: –
“Four eye witnesses, at separate locations, saw the helicopter fly towards the west in a controlled
manner with its searchlight illuminated. They then described the helicopter turning rapidly two or
three times whilst descending in a nose down attitude before striking the ground. Some of the
witnesses described unusual sounds from the engine variously described as “grinding”, “slowing
down” or “dying”. In practice, it is difficult to differentiate the sound of a helicopter’s engines from
the sounds of the main and tail rotors. These latter sounds vary significantly if a helicopter is
manoeuvred aggressively and it seems likely that it was these variations in rotor blade noises that
were heard by the witnesses. This possibility is supported by the lack of comment by the crew on
abnormal engine behaviour and by the results of the post crash investigation, which indicated that the engines had behaved normally up to the point of impact.”
http://www.aaib.gov.uk/publications/bulletins/august_2003/eurocopter_023427.cfm
This was issued later
Corrigendum – Eurocopter EC135T1, G-SPAU and may be pertinent
http://www.aaib.gov.uk/publications/bulletins/september_2003/corrigendum_023918.cfm
Directed EMP? If the rotors weren’t turning….. and I can’t think of anything that might just cause a cab to fall out of the sky like a stone….except EMP switching everything off. No time for a reset if it was low burst, no free wheeling as gearbox still engaged.
I’d have the chips tested. Very odd indeed.
I’ve also been thinking that total electrical failure is the answer. However it sounds like the spotlight was still illuminated as it went down. I don’t know the fuel pump power supply arrangement on this class of aircraft, but usually its pretty failproof.
Keith W,
Well, that’s another one although I don’t buy authoritarian bleats ‘They are not airworthy, “because they were not manufactured in accordance with an approved type design.”‘. Thwack.
What they mean by airworthy is documentary.
The rotor was
cut offremoved before the craft was lifted from the building. That would make basic function check impossible but these people will be well aware of preserving evidence.Looking at reports on the PPRUNE and the AAIB websites it appears that the rotorhead was NOT cut off, they removed the rotors and lifted the aircraft out by the rotorhead.
http://www.aaib.gov.uk/publications/special_bulletins/s9_2013___eurocopter_ec135_t2___g_spao.cfm
One suggestion made by a helicopter pilots was that a compressor surge could have stalled the engines. If this happened it may have appeared to the pilot as an engine failure. Standard procedure in that case is to turn off the engines and do an emergency autorotate landing. Applying too much collective pitch during a autorotation landing he could end up with a stationary rotor 60 ft above the ground. I believe that such emergency landings in bad visibility or at night are very hard to pull off.
Analysis of the FADEC chips on the engines should reveal any electrical power failure and have the last engine throttle settings still recorded.
A DC-10 pilot in Chicago had an engine fall off his wing during takeoff, it took all the hydraulics with it.
Near as I remember, the cockpit recorder only recorded the pilot as saying: “damn”.
The plane went inverted and hit the ground with a full load of fuel.
271 people died.
No time for platitudes, when the controls are to the stops and not correcting the problem.
http://en.wikipedia.org/wiki/American_Airlines_Flight_191
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Way too early to be guessing about causes.