Pretty much what happened at Kegworth.
http://en.wikipedia.org/wiki/Kegworth_air_disaster
http://en.wikipedia.org/wiki/Kegworth_air_disaster
Ed Helicopter Crashes into Glasgow Pub
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BenBurch
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The fire alarm being wired backwards takes most of the blame I believe.
ETA: No, I see they ruled that out. I had recalled it from the time.
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Darth Rotor
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I have read extensively the AAIB report, and the discussions among EC-135 pilots and Police Pilots in the UK on the PPRuNe forums.
It is difficult for me to figure why the Prime Pumps were on (used mostly for starting) and the Transfer pumps were off (used to get the last remaining fuel into the engine supply tanks) beyond the age old problem of what we used to call "switchology." In the dark, all four switches feel the same (round) but one set is on one side of the switch cluster, and the other set is on the other side. As I understand it, it is not uncommon to have to switch the transfer pumps on, or off, in flight depending on fuel state and how much hover work one has done near the limit of fuel endurance.
So, my guess is that with the intention of tripping on the transfer pumps, he switched on the prime pumps (of little use in flight most of the time) and was also probably coordinating some comms with the air traffic folks to get him back to base, and maybe talking to his crew (the two cops along for the police mission) about something.
That tells me that once the first engine crapped out, he was surprised, and was sorting through "can I limp it back to base or not" when the second crapped out and he was surprised by the dual engine failure, which meant that over Ubran Terrain, a night autorotation with him behind the problem with Rotor Speed control (EC-135 is a low inertia rotor head) made for a less than acceptable autorotation.
From me to you all: if you told me that, over a very built up urban area, in a twin, that 'your engines will fail in half a second' at night a few hundred feet over a major city ... even with that warning, once the engines wound down, a night autorotation over built up urban area is sporting at best. Being a second or two behind the problem due to surprise at the second engine going dead ... not sure how well I would have done.
Igor Sikorsky wept.
It is difficult for me to figure why the Prime Pumps were on (used mostly for starting) and the Transfer pumps were off (used to get the last remaining fuel into the engine supply tanks) beyond the age old problem of what we used to call "switchology." In the dark, all four switches feel the same (round) but one set is on one side of the switch cluster, and the other set is on the other side. As I understand it, it is not uncommon to have to switch the transfer pumps on, or off, in flight depending on fuel state and how much hover work one has done near the limit of fuel endurance.
So, my guess is that with the intention of tripping on the transfer pumps, he switched on the prime pumps (of little use in flight most of the time) and was also probably coordinating some comms with the air traffic folks to get him back to base, and maybe talking to his crew (the two cops along for the police mission) about something.
That tells me that once the first engine crapped out, he was surprised, and was sorting through "can I limp it back to base or not" when the second crapped out and he was surprised by the dual engine failure, which meant that over Ubran Terrain, a night autorotation with him behind the problem with Rotor Speed control (EC-135 is a low inertia rotor head) made for a less than acceptable autorotation.
From me to you all: if you told me that, over a very built up urban area, in a twin, that 'your engines will fail in half a second' at night a few hundred feet over a major city ... even with that warning, once the engines wound down, a night autorotation over built up urban area is sporting at best. Being a second or two behind the problem due to surprise at the second engine going dead ... not sure how well I would have done.
Igor Sikorsky wept.
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Rat
Not bored. Never bored.,
Didn't I say that a couple of pages back?
That really sums it up. Especially your second paragraph. If I had to assign a probability of likelihood that your above summation was accurate I would put it in the 90% likely range based on my experience.
Its actually a simple explanation.
Its an explanation that matches the facts.
Its an explanation that is known to have occurred in the past (generally speaking).
LondonJohn...you seem to be banking an awful lot of making assumption of what the pilot knew and when in ruling out plain old human error. Just because there are warning annunciations in no way sheds light on what a pilot has going on in his head at a given time. Have you ever done something in a certain way because you were 100% convinced of your actions...only to find out you were so wrong that your previous thoughts were hard to explain? Well that happens to pilots too.
It is loss of situational awareness. But this type of loss of situational awareness is not the kind were you dont know whats going on....its the type were you are absolutely certain you know whats going on...but are in error. So much so that subtle cues may not register. Problem is.. when the error is exposed to the person engulfed in this type of loss of situational awareness...there is usually a brief moment of denial. Thats when the SHTF.
One classic example of this is Eastern Air Lines Flight 401 that crashed in the Everglades. You can click the link below for a recreation of the CVR. But there are hundreds of other just like it.
https://www.youtube.com/watch?v=ICqPGkto3Yo
LondonJohn
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Inasmuch as they shut down the wrong engine, yes.
But in the Kegworth case, there was a combination of further near-incredible factors that came into play with devastating effect. The most important of these was that when the pilots shut down the wrong engine, the autothrottle on the other engine (the one that had actually broken a fan blade) throttled down and temporarily cleared the problem by stopping the vibration and the combustion of excess fuel. This led the pilots to believe - incorrectly - that they had remedied the situation and that they had indeed shut down the correct (malfunctioning) engine. Had this unfortunate consequence not happened - and had the malfunctioning engine continued to malfunction when the pilots shut down the wrong (healthy) engine, it's pretty certain that the pilots would quickly have realised that they had shut down the wrong engine and remedied the situation properly.
In addition, the primary reason why the pilots shut down the wrong engine in the first place was that they were flying a new variant of the 737 on which they had not received adequate upgrade training. On the previous models of 737, the aircon was powered by only one engine. When the pilots smelled smoke in the cockpit, they therefore assumed that they could immediately identify the malfunctioning engine from what they thought was correct knowledge of the connectivity of the aircon system. What they didn't know was that in this new variant of 737, the aircon was powered and fed by both engines.
LondonJohn
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I've already said that in my opinion Eastern 401 was a very different scenario. In that instance (as in so many others), the pilots were not aware that the aircraft was in imminent peril. Yes, they were preoccupied with other issues, and lacked situational awareness. But there were not indicators in front of their faces that the aircraft was about to impact the ground, and neither was the problem with which they became preoccupied one which, in itself, would have caused the aircraft to effect a controlled or uncontrolled flight into terrain.
In my view, those differences are critical. In the case of the Glasgow helicopter crash, the very alarm that first alerted the pilot was one which - if ignored or uncorrected - would with total certainty have caused the aircraft to crash. That's a massive difference. The pilot was alerted to a situation which was explicitly clear and with explicitly clear consequences: the fuel in the supply tanks was running out, and if it totally ran out the helicopter would fall out of the sky.
What's more, in assessing the situation, the pilot would by definition have to have been looking at the very instruments (the fuel gauges) that were telling him - in unequivocal terms - that a) he clearly hadn't remedied the problem, and b) the fuel volume in the supply tanks was continuing to drain towards empty. This is not a situation where the pilot could - by any reasonable assessment whatsoever - have been preoccupied dealing with something else that was totally unrelated to the fuel supply situation.
You seem to be suggesting in your posts directed at me that I am either ignorant of, or unfamiliar with, the concepts of situational awareness, pilot over-confidence, cumulative pilot error or sheer bad luck. In fact, I am well aware of all of these. They indeed explain accidents such as Eastern 401 (and Kegworth). In my opinion, they do not explain the Glasgow helicopter crash right now.
LondonJohn
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Yes, you may well be correct. But if that was what did happen, then how can one explain the dual facts that a) the alarms didn't stop, but rather they not only continued but actually increased in number and urgency, and b) the fuel tank levels - which the pilot could quite clearly see in front of his face - was unequivocally continuing to fall towards empty?
Are you suggesting that the pilot flicked the switches and thought he'd solved the problem (and I can certainly buy that part), but then not only failed to check whether his actions had had the desired effect, but also completely ignored the dual facts that the alarms were increasing and the indicated supply tank fuel levels were continuing to fall rapidly towards zero? Because I find it incredibly hard to believe that second part.
I believe that the evidence shows that the pilot made no radio calls to ATC or anyone else from the moment of the first low-fuel alarms.
You're saying that you wouldn't even have attempted an autorotation landing? And you're suggesting that you wouldn't have instinctively made a short urgent radio transmission to say you were going down?
And anyhow, I still have to come back to this "surprised at the engines flaming out" element of your suggestion. The pilot knew he had a critical fuel supply problem. He obviously knew that if the engines ran out of fuel they would flame out and shut down. He knew that the low-fuel alarms were sounding and getting more urgent. He could see at a glance the exact amount of remaining fuel in the supply tanks (and the sensors and instruments were all in perfect working order and totally accurate). How on Earth could he have been completely taken by surprise when the two engines failed in quick succession?
Again, I want to point out that I am neither naive nor ignorant in the matter of human factors in aircraft accidents. However, I simply do not currently see how the "usual" array of contributory human factors can have been behind this particular accident.
Since you are making a positive claim here I am sure you can show the evidence for this claim?
From what I can see you do not seem to grasp human factors. Furthermore your hypothesis is quite absurd IMO. Your assessment would put the pilot in "criminal mastermind" territory. Disguising an intentional act like pilot error
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There are many examples beside Eastern 401 that have similar loss of awareness. Some regarding fuel and repeated warnings. United 173 was another one. There are many many many examples. But Eastern 401 is as good as any of them. You say in bold letter "the pilots were not aware they were in imminent peril". That is were the human factors come in to play. They should have known they were in imminent peril and had all the information being fed to them that this was the case. No different IMO. Ignore your altimeter info...ignore a CAS message.
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LondonJohn
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Huh? My evidence would be the clear, loud and highly visible "low fuel" alarms that started and then grew in number, frequency and urgency. It is entirely inconceivable that a medically-fit pilot would have failed to notice and comprehend these alarms.
From what I can see you do not seem to grasp human factors. Furthermore your hypothesis is quite absurd IMO. Your assessment would put the pilot in "criminal mastermind" territory. Disguising an intentional act like pilot error
"Criminal mastermind" territory?? Are you joking?! Pilot sees and hears "low fuel" alarms. Pilot attempts remedy. Pilot sees that remedy evidently has not worked. Pilot checks his remedy, or decides that he cannot take any further chances with the supply tank fuel levels running lower and lower (as evidenced by the large, graphic-and-numerical fuel quantity display right in front of his face), and decides to set down safely instead before the fuel available to the engines totally runs out.
Why didn't that happen? All I'm saying is that a) I don't know, and b) I don't think it can be explained by the usual human factors behind most airline accidents. I am saying that one possible explanation is that the pilot knew what he was doing (and not doing), and knew its consequences. There may be other explanations. I hope there are. What I am saying is that in my opinion, the usual human factors do not appear to provide an adequate explanation.
But your hostility is noted........
LondonJohn
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But the difference in this case - which I tried to point out previously - is that the incident that might have preoccupied the Glasgow pilot was exactly the incident that ultimately resulted in the loss of the aircraft. If the pilot had, say, had a problem with his radio that he was trying to sort out, or if he was perhaps lost over dark rural countryside on a dark night and was trying to figure out his location, it's perhaps just possible that he might have missed/ignored/misinterpreted the increasing low-fuel alarms.
In the United 173 example, the crew were attempting to address and remedy a landing gear problem. And that's why they didn't notice that they were getting critically low on fuel: they were preoccupied with a totally different and unrelated problem. Furthermore, the aircraft in question (a DC-8) had primitive and unreliable fuel gauges, and only a small, minor "low fuel" alarm.
In the Glasgow helicopter, there were state-of-the-art digital instruments right in front of the pilot, telling him with total clarity and accuracy, in graphical and numerical representation, exactly how much fuel there was in the two supply tanks and the main tank. And there was a much more sophisticated system of "low fuel" alarms, which increased in number, frequency and urgency as the fuel in the supply tanks got lower and lower.
If you like, you can keep throwing other air crash examples in my direction. And I will be able to show you exactly how and why they differ from the Glasgow crash in human factors terms. In the case of United 173 (as in Eastern 401), the massive difference was that the crew were preoccupied dealing with a totally separate and unrelated problem. Do you have any more?
commandlinegamer
Philosopher
How many times have you turned the gas on under the wrong pot on the hob? Switched off the VCR instead of the TV? Clicked on Internet Explorer when you really wanted to open Microsoft Word? Put the car in reverse instead of first gear?
You do something which isn't what you intended and you can't explain why.
Is it always stress, or simple distraction?
And can we ever eliminate the possibility of this happening in mission-critical situations.
Insert Princess Bride quote here.
LondonJohn
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LondonJohn
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Absolutely agree.
But, to use one of your examples, if you put your car into reverse gear by mistake, would you set off gaily in reverse without noticing? Even when you could see the scenery going past in the opposite direction to that which you were expecting? And what if there was a warning system in your car that alarmed (lights and sounds) at first to indicate "You're going in reverse". Then a few seconds later: "Warning! You're going in reverse!". The a few seconds later: "WARNING! YOU'RE IN REVERSE! YOU ARE GOING TO CRASH!" And if there was a sizeable graphical indicator in front of you on your dashboard,in the "which gear are you in?" box, which clearly indicated "Reverse".
I fully agree that mistakes can be - and are - often made, and that sometimes they are mistakes that have potentially grave (and fatal) consequences. And I also agree that mistakes can be piled onto mistakes, to make the overall situation exponentially worse.
But what I find hard to understand is a situation where (seemingly) only one mistake has been made, and where attention has been repeatedly and explicitly drawn to that mistake, and where seemingly no effort has even been made to address - far less rectify - that mistake (whether by actively correcting the mistake, or by taking the necessary steps to stop the process in order to figure out what's going on (in the car-in-reverse example, to apply the brakes and stop the case; in the Glasgow helicopter example, to land the helicopter safely while there was still adequate fuel in the supply tanks).
Skwinty
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Bearing in mind that the helicopter was at an altitude of 1000' AGL, there was very little time before impact to analyse and correct any apparent fault. The pilot could have believed he still had another 10 minutes of fuel left. Had the rotors not already stalled there still would have insufficient time to correct the fuel configuration and effect an engine restart.
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Distraction, leading to unexpected results, leading to stress, adding to distraction and snowballing from there.
@LondonJohn: when you're in an aircraft, close to the ground, trying to sort out what just went wrong, the last thing you do is jump on the radio. In order of priority, we teach aviate, navigate, communicate. If the pilot involved had his hands full of helicopter that suddenly was not behaving as expected, there's likely a good chance he was trying desperately to aviate.
I'm not a rotorhead, so I certainly don't know the systems on the EC-135 (I keep thinking of USAF Boeing variants when I read that), so I'll defer to those experts regarding why autorotation was lost as an option. I am going to the Helicopter Association International convention in Anaheim next week, so I'll do some looking/asking.
LondonJohn
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If you're referring to the final moments when the engines flamed out and the helicopter started falling from the sky, then yes, of course radio comms should not have been the pilot's main priority (I used to hold a private pilot's licence, so I do also have some understanding of emergency protocols). However, I'd point out that a) this was one of the things he should have done at some point (and which the evidence can unequivocally prove that he didn't do), and b) he also didn't appear to do much "aviation" either. There's absolutely no evidence that he even tried to execute an autorotate landing. So it's a little difficult to accept that he was "desperately trying to aviate", when the avation procedure he should have been performing was one that is drummed into every qualified helicopter pilot as part of basic emergency training.
But if you're referring to the initial onset of the problem - the onset of the "low fuel" alarms - then I'd also argue that the pilot failed to "aviate", in addition to a failure to "communicate". He self-evidently didn't fix the problem that was (literally) staring him in the face and (literally) shouting its presence to him. The one thing he did appear to do was "navigate". He appeared to be consciously and deliberately piloting his aircraft - an aircraft in which escalating "low fuel" alarms were blaring out, and where the fuel gauges in front of the pilot's eyes were rapidly bleeding out to zero - back towards his base, taking him over the densely-populated centre of Glasgow.
Can you explain that?