Police helicopter crashes onto Glasgow pub
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Is anyone else getting frustrated that people don't seem to understand the fact that the A\C descended vertically, confirmed by the AAIB and eye witnesses, and there was no evidence of rotational damage to the MR blades meaning they were not rotating normally? Is there really any point re-hashing all the autorotation theories over and over? 
I accept an attempt may have been made to autorotate, but due an as yet unknown reason it didn't end that way.
I accept an attempt may have been made to autorotate, but due an as yet unknown reason it didn't end that way.
Last edited by Jetdriver; 5th Dec 2013 at 16:13.
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My feelings too. No visible damage to the MRBs does not necessarily mean they weren't turning, just that they weren't turning under power, or they never struck anything
Last edited by Bladecrack; 4th Dec 2013 at 22:04.
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Does anyone else not see that a helicopter without the blades turning cannot fly? Are you proposing they seized solid in flight? Do you know the effect this would have on a helicopter? It would of disintegrated in flight.
The impact shows it did not strike the ground in full free fall, the damage would of been much, much worse. In my opinion the head was producing some lift at, or shortly before the impact, therefore it had to be turning.
As for witness statements, they aren't worth the paper they are written on. As proved by Psychologists the world over. 10 witnesses, 10 versions, which is correct?
I'm not a pilot, but I am a type rated LAE on the EC135 for many years, I know how the aircraft works intimately.
The impact shows it did not strike the ground in full free fall, the damage would of been much, much worse. In my opinion the head was producing some lift at, or shortly before the impact, therefore it had to be turning.
As for witness statements, they aren't worth the paper they are written on. As proved by Psychologists the world over. 10 witnesses, 10 versions, which is correct?
I'm not a pilot, but I am a type rated LAE on the EC135 for many years, I know how the aircraft works intimately.
Bladecrack: point taken on reports of the helicopter falling, but please consider that at 2230 hours or so, when this event took place, the eyewitnesses had what visual cues upon which to base the reported observations?
What the condition of the rotor blades implies has been previously covered.
The matter of inertia: if in a hover, or flying at a selected transit / cruise speed, rotors at flight RPM don't just stop on a dime. Even low inertia heads have a crap load of momentum at flight RPM. So the event breaks down into four rough phases:
a. Flying along/hovering along/doing mission
b. Something happens
c. Descent begins
d. Descent ends.
(* no evidence so far available that between B and C an ascent (short duration?) can be added to this sequence)
Inside each phase a variety of things can be happening, which will in all likelihood be pieced together in sequence by the investigators as they apply their skills and resources.
The transition from phase a to phase c took ... how long?
Unknown by the observers on the ground. From the post here by scooby, it appears to have been in phase c when the observer on the parking lot roof picked up his visual cues, which he then lost before the impact with the pub. For how many seconds, in the dark, did he track the object in the sky?
(As an aside, I once took my wife to watch helicopters take off and land at a training field. As I was paying attention to another aircraft, she gave a little gasp and said" It's falling!"
I looked up and saw a CH-53E doing a practice autorotation. No big deal.
To the untrained eye, it looked like it was falling ... and this was in daylight.)
What the condition of the rotor blades implies has been previously covered.
The matter of inertia: if in a hover, or flying at a selected transit / cruise speed, rotors at flight RPM don't just stop on a dime. Even low inertia heads have a crap load of momentum at flight RPM. So the event breaks down into four rough phases:
a. Flying along/hovering along/doing mission
b. Something happens
c. Descent begins
d. Descent ends.
(* no evidence so far available that between B and C an ascent (short duration?) can be added to this sequence)
Inside each phase a variety of things can be happening, which will in all likelihood be pieced together in sequence by the investigators as they apply their skills and resources.
The transition from phase a to phase c took ... how long?
Unknown by the observers on the ground. From the post here by scooby, it appears to have been in phase c when the observer on the parking lot roof picked up his visual cues, which he then lost before the impact with the pub. For how many seconds, in the dark, did he track the object in the sky?
(As an aside, I once took my wife to watch helicopters take off and land at a training field. As I was paying attention to another aircraft, she gave a little gasp and said" It's falling!"
I looked up and saw a CH-53E doing a practice autorotation. No big deal.
To the untrained eye, it looked like it was falling ... and this was in daylight.)
Once RRPM gets below a certain threshold and descent rate exceeds a certain value a fully developed blade stall will occur. In a low inertia rotor this will literally stop it in no time. (I Count everything below 50RPM as stopped). Parts falling off can't achieve nearly the same level of energy Dissipation that a fully developped stall can. Combine this with no engine power (for whatever reason) and you will have the blades completely stopped in about 5 - 10s.
In a flare after an autorotation the blades are operating in an area of drag significantly below the drag when fully stalled yet you will dissipate the energy in the rotor System within a few seconds.
So you stall the rotor and it will come to a halt very quickly. Parts breaking off or not.
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Regarding no damage to rotor blades. A far from definitive but intriguing thought;
Helicopter instructor praised for quick actions - National - NZ Herald News
Link to an article with details of an accident where a composite blade set struck the ground. It's not safe to assume that it was at rpm for flight (530rpm is 100%). Even at 80%, 424 rpm should be enough to produce significant damage.
There are differences, terrain, rod, aod, inertia and many others, but my assumption was also originally that intact blades indicate no rotational forces, but.....
Helicopter instructor praised for quick actions - National - NZ Herald News
Link to an article with details of an accident where a composite blade set struck the ground. It's not safe to assume that it was at rpm for flight (530rpm is 100%). Even at 80%, 424 rpm should be enough to produce significant damage.
There are differences, terrain, rod, aod, inertia and many others, but my assumption was also originally that intact blades indicate no rotational forces, but.....
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Scoobydroo#552 writes: [The editor of the Scottish Sun] is clear that the helicopter was eerily quiet ... he got to the site (250m) ... emergency services were arriving ... He ran round the corner into Argyll Street ... He spoke to a policeman in Argyll Street who was totally unaware of the helicopter coming down ...
A man trained to notice things says "eerily quiet" and a policeman around the corner heard nothing out of the ordinary. How little noise can a turbine make?
As I have said before, the editor was on his phone. He is a reporter. Would he not have recorded the descent?
A man trained to notice things says "eerily quiet" and a policeman around the corner heard nothing out of the ordinary. How little noise can a turbine make?
As I have said before, the editor was on his phone. He is a reporter. Would he not have recorded the descent?
A catastrophic MGB failure would not even cause the Blades to stop turning....but it would make them and the gearbox depart the aircraft in all likelihood due to the massive forces created by that event.
Harken back to a North Sea crash a while back.
A more gradual failure of some sort....perhaps they might slow....but in all likelihood both Engines would still be applying power to the MGB.
As to the AAIB comment.....All Descents are Vertical by definition....and we should not put too much credence in that very short, vague, comment as there was no additional discussion of the manner or pitch of that Descent.
The AAIB will have a Preliminary Report of some sort for public consumption within a very short period of time due to the massive public interest in this tragedy.
What they say in that will begin to point us in the direction they will be going in their investigation.
Harken back to a North Sea crash a while back.
A more gradual failure of some sort....perhaps they might slow....but in all likelihood both Engines would still be applying power to the MGB.
As to the AAIB comment.....All Descents are Vertical by definition....and we should not put too much credence in that very short, vague, comment as there was no additional discussion of the manner or pitch of that Descent.
The AAIB will have a Preliminary Report of some sort for public consumption within a very short period of time due to the massive public interest in this tragedy.
What they say in that will begin to point us in the direction they will be going in their investigation.
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Angular momentum
My understanding is that you can't "tumble" a helicopter with turning rotors. It would be like trying to tumble a big gyroscope…. you'd just hurt your wrists, and be left with a surprised look on your face.
If it were to tumble, then I suspect the gearbox would have severe damage after that happened, even if it was intact before.
If it were to tumble, then I suspect the gearbox would have severe damage after that happened, even if it was intact before.
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As for witness statements, they aren't worth the paper they are written on.
At least two posts refer to witness statements as being worthless. This is quite incorrect. In a previous incarnation I was a Met police officer and took a great many statements - some of them from quite young people. Their accuracy was often remarkable and enabled offenders to be identified and convicted.
Much depends on the type of event being witnessed. Fast moving events are difficult and I can appreciate that a helicopter falling from the sky on a dark night will not be easy to describe. However, if a witness says it was tumbling over and over then you may be fairly certain it did not come down in a fixed orientation. And that may be of some help in understanding this tragedy.
At least two posts refer to witness statements as being worthless. This is quite incorrect. In a previous incarnation I was a Met police officer and took a great many statements - some of them from quite young people. Their accuracy was often remarkable and enabled offenders to be identified and convicted.
Much depends on the type of event being witnessed. Fast moving events are difficult and I can appreciate that a helicopter falling from the sky on a dark night will not be easy to describe. However, if a witness says it was tumbling over and over then you may be fairly certain it did not come down in a fixed orientation. And that may be of some help in understanding this tragedy.
Avoid imitations
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RWB2,
Agreed. At least for some, if not all of the descent.
The impact shows it did not strike the ground in full free fall, the damage would of been much, much worse. In my opinion the head was producing some lift at, or shortly before the impact, therefore it had to be turning.
The_flying_cop
Hey totally respect for that middle of the road comment in these bad circumstances, that may also give some closure to the hangerongers and press leaches on these forums !
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From post 598: "My feelings too. No visible damage to the MRBs does not necessarily mean they weren't turning, just that they weren't turning under power, or they never struck anything."
The image in the link below (it is the penultimate image in the slideshow) is one I have frequently retuned to. Given that much of the roof area has been discussed in this thread, I am surprised (as far as I can see) that what appears to be obvious signs of some (albeit minimal) signs of MRB movement has not been mentioned.
The visible damage to the roof, by what appears to be rotors running counter clockwise, would seem to lend some interpretation of the velocity of the aircraft, the speed the rotors were turning, and perhaps even the pitch of the rotor blades.
BBC News - In pictures: Helicopter wreckage lifted from Glasgow bar
Of course all we purport here is conjecture - some of which is more informed and informative than others; with this in mind, on discussing the suggestions offered in this forum with my husband he raised the hypothesis that perhaps an incident in the cockpit (such as a damaged CS canister) could have been in some way responsible.
The image in the link below (it is the penultimate image in the slideshow) is one I have frequently retuned to. Given that much of the roof area has been discussed in this thread, I am surprised (as far as I can see) that what appears to be obvious signs of some (albeit minimal) signs of MRB movement has not been mentioned.
The visible damage to the roof, by what appears to be rotors running counter clockwise, would seem to lend some interpretation of the velocity of the aircraft, the speed the rotors were turning, and perhaps even the pitch of the rotor blades.
BBC News - In pictures: Helicopter wreckage lifted from Glasgow bar
Of course all we purport here is conjecture - some of which is more informed and informative than others; with this in mind, on discussing the suggestions offered in this forum with my husband he raised the hypothesis that perhaps an incident in the cockpit (such as a damaged CS canister) could have been in some way responsible.
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I don't mention stopped engines. Who has? There's no evidence for that is there? Where do you get this from? Let's stick to the facts s far as we know them shall we?
Gordon Smart, editor of the Sun's Scottish edition, saw the crash from a multi-storey car park nearby.
He told Sky News: "I thought it was a plane that was going to crash. I looked up at the sky and I could see the helicopter falling, tumbling ... and then there was an eerie silence for the last part of the fall.
He told Sky News: "I thought it was a plane that was going to crash. I looked up at the sky and I could see the helicopter falling, tumbling ... and then there was an eerie silence for the last part of the fall.
they may not have been turning all that fast but "stopped" is a very specific and definitive statement and we have no shred of evidence that this is the case.
Not turning at full speed I grant you, but there's a world of variation in between.
Not turning at full speed I grant you, but there's a world of variation in between.
Let's keep this thread to real rotorheads, not sim walts please.
Please, stay away if you have no idea,,,
Please, stay away if you have no idea,,,
There is an EMS 135 that flies over the House quite often....and I am beswitched to tell you I am hearing "Engine" noise. I can identify the beat of the Rotor depending upon the distance and direction it passes by....and I would probably imagine I am hearing some of the Fenstron noise....but as to exactly what sound other than the Rotor Blades I am hearing....I would not offer a guess should an Investigator ask me.....that with having been a Helicopter Pilot since 1967.
I would be able probably to state if it sounded as it normally does....but even then that would be a subjective opinion not based upon any empirical observation.
For a complete Novice to look up into the night sky....with all sorts of City Noise going on around him....I doubt very much they could do any better.
I would be able probably to state if it sounded as it normally does....but even then that would be a subjective opinion not based upon any empirical observation.
For a complete Novice to look up into the night sky....with all sorts of City Noise going on around him....I doubt very much they could do any better.
AB
Quote:
Agaricus bisporus - how do you explain stopped engines and stopped rotors with the above scenario? If the pilot was incapacitated how could he shut down the engines?
I don't mention stopped engines. Who has? There's no evidence for that is there? Where do you get this from? Let's stick to the facts s far as we know them shall we?
There's a lot of crap about "stopped" rotors too. Complete hogwash. How the **** can rotors be "stopped" in the few seconds it takes to fall from what - guessing here - 700 to 1000ft? all but impossible. How long does it take the rotor brake to do that? Longer than the time to fall that far I'd guess. Sure. they may not have been turning all that fast but "stopped" is a very specific and definitive statement and we have no shred of evidence that this is the case.
Not turning at full speed I grant you, but there's a world of variation in between.
Why do I have to reiterate the unlikeliness of "bird strike on the fenestron" fer chrissakes? At 120 Kts it ill hardly affect anything even if such a fantastical scenario could have happened. It certainly wouldn't result in the helo coming out of the sky like a fish supper. Do some people not understand what a fenestron is or how it works? If not, avast posting please. Let's keep this thread to real rotorheads, not sim walts please.
I'm glad you've discovered no bird remains. Have you told the AAIB?
ditto "vertical descent" - clearly not the case as anyone can see. It didn't drive into the roof with no speed did it?
"shut down engines" Eh???? who said this????
Ditto "no engines" wtf do you get this nonsense from??
ditto "no rotor speed".
Please, stay away if you have no idea,,,
Hopefully this is not an AAIB preminaly report! Who deserved that rant and speculation from a very aggressive person! Show some respect whoever you are or show justification, for your rants?
Agaricus bisporus - how do you explain stopped engines and stopped rotors with the above scenario? If the pilot was incapacitated how could he shut down the engines?
I don't mention stopped engines. Who has? There's no evidence for that is there? Where do you get this from? Let's stick to the facts s far as we know them shall we?
There's a lot of crap about "stopped" rotors too. Complete hogwash. How the **** can rotors be "stopped" in the few seconds it takes to fall from what - guessing here - 700 to 1000ft? all but impossible. How long does it take the rotor brake to do that? Longer than the time to fall that far I'd guess. Sure. they may not have been turning all that fast but "stopped" is a very specific and definitive statement and we have no shred of evidence that this is the case.
Not turning at full speed I grant you, but there's a world of variation in between.
Why do I have to reiterate the unlikeliness of "bird strike on the fenestron" fer chrissakes? At 120 Kts it ill hardly affect anything even if such a fantastical scenario could have happened. It certainly wouldn't result in the helo coming out of the sky like a fish supper. Do some people not understand what a fenestron is or how it works? If not, avast posting please. Let's keep this thread to real rotorheads, not sim walts please.
I'm glad you've discovered no bird remains. Have you told the AAIB?
ditto "vertical descent" - clearly not the case as anyone can see. It didn't drive into the roof with no speed did it?
"shut down engines" Eh???? who said this????
Ditto "no engines" wtf do you get this nonsense from??
ditto "no rotor speed".
Please, stay away if you have no idea,,,
Hopefully this is not an AAIB preminaly report! Who deserved that rant and speculation from a very aggressive person! Show some respect whoever you are or show justification, for your rants?