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Summary, rather than the full report, from the AAIB website...
The helicopter departed Glasgow City Heliport (GCH) at 2044 hrs on 29 November 2013, in support of Police Scotland operations. On board were the pilot and two Police Observers. After their initial task, south of Glasgow City Centre, they completed four more tasks; one in Dalkeith, Midlothian, and three others to the east of Glasgow, before routing back towards the heliport. When the helicopter was about 2.7 nm from GCH, the right engine flamed out. Shortly afterwards, the left engine also flamed out. An autorotation, flare recovery and landing were not achieved and the helicopter descended at a high rate onto the roof of the Clutha Vaults Bar, which collapsed. The three occupants in the helicopter and seven people in the bar were fatally injured. Eleven others in the bar were seriously injured.Fuel in the helicopter’s main fuel tank is pumped by two transfer pumps into a supply tank, which is divided into two cells. Each cell of the supply tank feeds its respective engine. During subsequent examination of the helicopter, 76 kg of fuel was recovered from the main fuel tank. However, the supply tank was found to have been empty at the time of impact. It was deduced from wreckage examination and testing that both fuel transfer pumps in the main tank had been selected off for a sustained period before the accident, leaving the fuel in the main tank, unusable. The low fuel 1 and low fuel 2 warning captions, and their associated audio attention-getters, had been triggered and acknowledged, after which, the flight had continued beyond the 10-minute period specified in the Pilot’s Checklist Emergency and Malfunction Procedures.
The helicopter was not required to have, and was not fitted with, flight recorders. However, data and recordings were recovered from non-volatile memory (NVM) in systems on board the helicopter, and radar, radio, police equipment and CCTV recordings were also examined.
During the investigation, the EC135’s fuel sensing, gauging and indication system, and the Caution Advisory Display and Warning Unit were thoroughly examined. This included tests resulting from an incident involving another EC135 T2+.
Despite extensive analysis of the limited evidence available, it was not possible to determine why both fuel transfer pumps in the main tank remained off during the latter part of the flight, why the helicopter did not land within the time specified following activation of the low fuel warnings and why a MAYDAY call was not received from the pilot. Also, it was not possible to establish why a more successful autorotation and landing was not achieved, albeit in particularly demanding circumstances.
The investigation identified the following causal factors:
73 kg of usable fuel in the main tank became unusable as a result of the fuel transfer pumps being switched off for unknown reasons.
It was calculated that the helicopter did not land within the 10-minute period specified in the Pilot’s Checklist Emergency and Malfunction Procedures, following continuous activation of the low fuel warnings, for unknown reasons.
Both engines flamed out sequentially while the helicopter was airborne, as a result of fuel starvation, due to depletion of the supply tank contents.
A successful autorotation and landing was not achieved, for unknown reasons.
The investigation identified the following contributory factors:Incorrect management of the fuel system allows useable fuel to remain in the main tank while the contents in the supply tank become depleted.
The RADALT and steerable landing light were unpowered after the second engine flamed out, leading to a loss of height information and reduced visual cues.
Both engines flamed out when the helicopter was flying over a built-up area.
Seven Safety Recommendations have been made.
Obviously I can understand the gist of the summary, but as a layman it just leaves me with the impression that the pilot must have done something or some things wrong? Is that likely to be it, or are there other things to consider?
Clearly an error in drills, the incorrect position of the transfer pumps switches has been clearly identified. Only the pilot would know the reason as to why that was.
As for the autorotation, well with little visual cues, no RADALT and landing lamp, he was on a hiding to nowhere. I imagine the drop from darkness into the street lights would disorientate him.
Such a bloody shame, but always the danger with single pilot flight, even if the right/left hand seat is trained to assist.
I'm not an expert at all either - all I can think is Germanwings 9525...
I heard about this earlier but there's more detail here.
I'm amazed it's possible to crash like that, that there isn't an auto override on those transfer pumps should fuel level become critical..!
That says it all really. Any speculation about why is purely that; speculation. So one cannot say with any certainty whether it was aircrew error or another unidentified reason.Despite extensive analysis of the limited evidence available, it was not possible to determine why both fuel transfer pumps in the main tank remained off
I guess it's a fine line between asking and speculating. So are these pumps they're talking about like operated by an old school switch on the control panel, or are they something that's operated by some other action or as part of a particular process?
Old school switches.
Thanks moose
Seen from the air the junction adjacent to the pub looks like quite a tempting open area to try to land a broken helicopter.
Guess we'll never know if that was the plan.
It's a very bizarre situation. From what I read there where numerous audible alarms warning the pilot to land within 10 mins yet he flew on for 16 before crashing with fuel onboard and the pumps switched off. If does start to look like a potentially deliberate crash and may explain why it hit a pub square on.
[u][b]jambalaya[/b][/u]
If does start to look like a potentially deliberate crash and may explain why it hit a pub square on.
How do you figure that?
It does read like either an extremely serious pilot error, or a suicide.aracer - Member
I'm not an expert at all either - all I can think is Germanwings 9525..
tbh before reading that, it hadn't even entered my mind.
I doubt we'll ever know to be honest. Although I do think from that a serious look into the pilots background is in order.
Or he could have been trying to push on and RTB? Because he really didn't fancy landing in the middle of the street and organising the recovery of the aircraft? He took a stupid gamble and it didn't pay off?
FFS, suicide is the first thing you jump to?
seems like an unlikely list of errors for a pilot to make? Happy to be corrected. I'm well aware i'm unqualified to comment, but it's a public report, people will be jumping to conclusions.moose - Member
FFS, suicide is the first thing you jump to?
Plus I know people affected that think the same, so I reckon it needs to be aleast ruled out, publicly. Alot of people will be thinking it.
Not at all, I've seen a similar gamble be made. If those transfer pumps were in the correct position it may have paid off. He could have had a hand faff and switched them on sooner, then forgotten when it all went pear shaped and switched them off. I've seen that almost happen before, but as we two front seaters, everything is identify and confirm. If somebody does something silly it's very quickly identified and remedied.
As for suicide, there is a far quicker and easier way of making yourself fall out of the sky. Transfer pumps in the grand scheme of things are far too innocuous to even bother with. Both ECL's back, fuel pumps off. you're going down quicker than a hooker from Holland.
[quote=moose ]FFS, suicide is the first thing you jump to?
When the pilot has switched off the fuel pumps and ignored two warnings, yes.
Unless of course somebody else switched off the fuel pumps and forced the pilot to keep flying.
It's not something I'd thought of at all before reading that either, but the reported sequence of events is one which is almost impossible to believe happening by accident.
How do you rule that out? His medical records will have been checked, there was nothing found or else it would have been mentioned. Don't forget the AAIB have no conflict of interest so they will happily share all the facts. They don't get sued as a result of their reports.
Cheers for that, like I say it's a public report and it leaves alot open for people to jump to conclusions. As I said, happy to be corrected and I accept your view point.
100% not pilot Suicide.
Some important switches in flight decks are 'guarded' - ie you need two actions to move them, remove a guard then action a switch. I don't know if the fuel transfer switches have this function on this aircraft.
Autorotation is what helo pilots do when the engines fail. It's hard at night because it requires a fine judgement at the end of the manoeuvre when close to the ground.
I think moose has it sadly ^^ 70-something kg of fuel is next to nothing to run two jet engines.
I can hazard a guess, but can someone remind me who the aircraft operator was (iirc the aircraft is contracted out to the Police)?
No one will ever know what really happened without a black box, it's all just educated / uneducated speculations...
[quote=tomkerton ]I think moose has it sadly ^^ 70-something kg of fuel is next to nothing to run two jet engines.
But he didn't use the 70kg. If he really was running low on fuel in the main tank (which the report appears to rule out) what advantage is there to turning off the transfer pumps?
They are warnings, they are there to highlight an issue so you can take corrective action. He chose to break from the drill, most likely to get back to base. His gamble didn't pay off and he killed himself, his crew, civilians and injured a few more.
It was a tragic accident. Nothing more, my 18 years experience says that. There are far easier ways to kill yourself in a helicopter than that.
OK, I'll defer to your experience, but what reason would you have for turning off the pumps?
Or he could have been trying to push on and RTB? Because he really didn't fancy landing in the middle of the street and organising the recovery of the aircraft? He took a stupid gamble and it didn't pay off?FFS, suicide is the first thing you jump to?
Well, considering the pilot clearly ignored every opportunity offered to him to get the bird down safely, and in one piece, it's an obvious conclusion to jump to, isn't it.
I mean, the pumps were switched off, the warning signs/sounds were ignored, autorotation into a brightly lit road junction was ignored, no mayday was called, how else can you explain the actions of a supposedly experienced, competent pilot?
So many factors about this crash are beyond comprehension, I really feel for the families of those who lost their lives, and who will forever be left asking how it could have possibly happened.
Moose - I've never flown single pilot commercial ops. Do you think police, air ambulance, pipeline inspection etc rotary will go two pilot now?
No good reason, that's the issue. I've seen finger faff too many times, especially when people are tired, panicking, under pressure. Could even have been the observer sat in the other seat, under direction of the pilot. A mistake was made, they paid for it. Them's the breaks in aviation, civilians paid the price too. Just a bloody shame.
[i]Seen from the air the junction adjacent to the pub looks like quite a tempting open area to try to land a broken helicopter.[/i]
It's a junction busy with traffic, I doubt the pilot would be attempting to land there. More likely hoping to dump it in the river which is on the opposite side of the road to the Clutha or land on one of the empty buildings round there.
autorotation into a brightly lit road junction was ignored
The location of the crash is entirely consistent with attempting autorotation into a brightly lit road junction.
I can imagine someone distractedly flicking off a couple of warnings, perhaps they are even similar to other warnings.
If this was suicide, it was needlessly elaborate.
Moose - I've never flown single pilot commercial ops. Do you think police, air ambulance, pipeline inspection etc rotary will go two pilot now?
Would this not need the incident rates to reach a certain level. I'm not convinced we are there yet, tragic accidents happen everywhere.
There's a lot of rotary flying from Scotland per capita.
More likely hoping to dump it in the river which is on the opposite side of the road to the Clutha or land on one of the empty buildings round there.
Seems reasonable.
@CountZero - No, it's not an 'obvious' conclusion to me. Maybe for someone that doesn't have a clue, yes.
@tomkerton - I doubt it, that kind of cost would break the bank.
99.99999% of people who read the report esentially. Tbh leaving it open for people to jump to the conclusion is fairly incompetent in itself.moose - Member
@CountZero - No, it's not an 'obvious' conclusion to me. Maybe for someone that doesn't have a clue, yes.
Look, the warnings illuminated, which indicated for him to land immediately as per the laid down drills, however there was still useable fuel in the tanks, that has been confirmed. Most airframes of that size have 100kg set as a minimum landing allowance. As in, that is the limit to which the warnings will illuminate and sounds. A man of his experience would know this, I personally think he was pushing back to base rather than having to land in an urban area. Unfortunately the transfer pumps were not doing their job as they were switched off, thus denying him that last bit of fuel. On my old airframe that fuel remaining would have give 7-8 mins flight time. Worst case you auto onto your pad.
Some important switches in flight decks are 'guarded' - ie you need two actions to move them, remove a guard then action a switch. I don't know if the fuel transfer switches have this function on this aircraft.
It says not in the main report, and likewise for the next door fuel transfer switches (? - I think that's what they were called). It goes on to say that, while these switches could in theory have been moved during the crash, other evidence showed that they were in the off position earlier in the flight.
Autorotation is what helo pilots do when the engines fail. It's hard at night because it requires a fine judgement at the end of the manoeuvre when close to the ground.
The main report also mentions that the pilot would have had to manually operate a guarded overhead switch to re power an altitude meter of some sort plus a landing light, that this would have been difficult given what else he would have been trying to control (the collective, whatever that is), and that without either the emergency landing timings would be very hard to judge at night time. (Apologies if I've misrepresented anything here helicopter folk, if I have its wholly unintentional).
I can hazard a guess, but can someone remind me who the aircraft operator was (iirc the aircraft is contracted out to the Police)?
Bond
[quote=moose ]No good reason, that's the issue. I've seen finger faff too many times, especially when people are tired, panicking, under pressure. Could even have been the observer sat in the other seat, under direction of the pilot. A mistake was made, they paid for it. Them's the breaks in aviation, civilians paid the price too. Just a bloody shame.
Fair enough, but when the warnings sound, would checking the transfer pump switches not be one of the first things you do? He had a good 10 minutes to do that.
moose - I accept your explainations, I've even posted your comments on another forum discussing it and jumping to the same conclusions.
I agee the whole deliberate crash is just a jump too far - pilot could have put the thing into any number of big, busy, well lit buildings nearby in Glasgow without need for any faffing - just steer.
It does seem that he may have been heading for junction next to or river near to to the bar - and didn't make it.
In the dark, in a split second, you could easily mistake a flat roof of the bar for an empty car park.
Awful incident all round.
Could have been the transfer pumps were switched on early, then switched off by mistake at the 10 minute point. Again, all supposition and without knowing exactly what the capacity the observers are trained to assist. I have seen some things in cockpits that would make your toes curl. Sometimes people make really bad decisions for no seemingly explainable reason.
Tragic for all involved and those left behind to come to terms with.
It said they don't need to log flight hours but I didn't read in any depth the training stuff so I don't know, I guess it's in there though.
Thanks for your explanation(s). A knowledgeable appraisal of the report summary was what I was interested in, rather than relying on the news websites.
Do the transfer pumps not get switched on at the start and left on then? I'm suspecting I don't understand what that report is saying as well as I'd thought...
Looks like they weren't turned on when they should have been. Just trying to get a copy of the pre-flight checks.
@moose thanks for the input. As I understand it there where "land soon" warnings which where ignored while overflying a major city. The risk management in deciding to press on just seems so crazy.
@jambalaya, in more normal circumstances it would have been a 50/50 decision. There's risk involved in landing in an uncleared area or pushing on. We unfortunately now know the repercussions of the latter.
seosamh77 - Member
99.99999% of people who read the report esentially. Tbh leaving it open for people to jump to the conclusion is fairly incompetent in itself.
The AAIB are there to determine the causes of aircraft crashes and make air safety recommendations. They are not there to determine who, if anyone, caused the crash. Their remit is that they do not apportion blame and can therefore be left to independently get to the cause of why an aircraft crashes without being seen as having any sort of political 'agenda'. Therefore, this report would not tell you why it appears there was a case of extremely questionable decision making going on in the cockpit of the aircraft at that time; if people thought that is what they would get then they have been misled. It is now over to the legal authorities to investigate further.
Hopefully the AAIBs recommendations re flight data/cockpit voice recording are taken on board as this may well have answered a lot of people's questions a lot sooner.