Ed Helicopter Crashes into Glasgow Pub

383LQ4SS said:
He then opened up that his fuel gauge had been broken for some time and they were simply estimting fuel load by putting a known quantity in prior to flight and then calculating use.
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How could that possibly be passed as airworthy? Surely that's grounds for a grounding until it's fixed?
 
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Craig B said:
Another strange suggested one has been fuel contamination.
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Thankfully unlikely these days; however some fuel supply problem, that would effect both engines, is one of the two main theories.

commandlinegamer said:
How could that possibly be passed as airworthy? Surely that's grounds for a grounding until it's fixed?
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Well it should but if it's the only helo available corners may be cut.
 
They've lifted the chopper out, after putting bands round it to hold it together. They're going to take it to Farnborough, and also examine and photograph every inch of the pub structure.

All the bodies that are known about have been removed, apparenly past a guard of honour made up of the emergency services. Now they're looking to see if there are any more. There are two or three rumours floating about regarding people who haven't been in contact since Friday night and who might possibly have gone to the gig at the Clutha. Let's hope they dn't find any more.

Rolfe.
 
Craig B said:
Obviously if there is a fault in that type of aircraft, it's imperative that it should be identified, but alleviating the anguish of the families must be the first priority.
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I wouldn't be surprised if the last bodies out were the ones directly underneath the helicopter. In that case lifting the helicopter was probably the most viable removal option.
 
That's more or less what they were saying on the news. It wasn't an either-or thing. The best and safest way to remove the helicopter was with extreme care, and the only way to get to these bodies was by doing exactly that.

They were also saying that there were three layers of roof - the original first-floor floor, and two roofs on top of that including one with a lot of sound-proofing, which led to an enormous amount of debris being brought down inside the pub.

ETA: Some pretty graphic photos of the damage here.

http://www.bbc.co.uk/news/uk-scotland-glasgow-west-25179128

Rolfe.
 
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I'm surely not the only one who keeps wondering why the pub was named after an ancient one, before realizing that I've misread it.
 
Yes, I think that was in response to the relatives who were questioning why not just take out the front of the building rather than winch the copter back through the roof hole.

Rolfe.
 
To some extent, but they built stuff to last in the Victorian era. I remember my mother trying to get a door fitted in an internal wall in the 1876 manse where we lived, to give access from the kitchen to the pantry without having to go out into the corridor every time. The internal wall was two feet thick. It took the builders days to get through it.

Rolfe.
 
Rolfe said:
To some extent, but they built stuff to last in the Victorian era.
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Varies. The problem the Victorians had is that their materials tended to have a variation between batches and their material science was only so so. That meant they often had no choice but to overbuild if they wanted something to stay up. On the other hand it took them quite a while to sort out boilers that didn't explode from time to time and they were prepared to build steeper embankments than modern engineers would opt for.
 
Overbuild - yeah, have you seen the Forth Bridge? On the other hand after what happened to the Tay Bridge, it's understandable.

Rolfe.
 
Rolfe said:
Overbuild - yeah, have you seen the Forth Bridge? On the other hand after what happened to the Tay Bridge, it's understandable.

Rolfe.
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And most Victorian sewer systems - most notably the magnificent London main sewer - were stupendously overbuilt (the irony being that Victorians severely underestimated the anticipated required stress on the sewer system over the following 100 years, meaning that their overengineering ended up coming in very handy indeed!).

And yeah, buildings/structures-wise, as others have also said, the relative youth of materials science and the highly-variable quality of basic building materials meant that overengineering was commonplace in the 19th Century. In addition, structural engineering was also in its infancy, and load analysis was somewhat basic*.

I'd imagine, therefore, that the supporting walls of the Clutha pub would have been substantial. Unfortunately, the roof would not have needed to have been built to handle loads anything like that experienced on Friday night.


* One of the things that made Brunel such an astonishing genius of civil engineering was his extraordinary (for his time) ability to conduct accurate stress/load analysis. Perhaps the epitome of his genius is the GWR bridge over the Thames at Maidenhead - he was presented with the problem of requiring a wide arch width (to allow for river traffic) but a relatively low arch height (i.e. the height of the railway line). His resulting arch design was revolutionary, and bore the load of the structure and the rail traffic with ease. Needless to say, it's still standing in its original form and part of the main trunk railway network to this day.
 
Rolfe said:
To some extent, but they built stuff to last in the Victorian era. I remember my mother trying to get a door fitted in an internal wall in the 1876 manse where we lived, to give access from the kitchen to the pantry without having to go out into the corridor every time. The internal wall was two feet thick. It took the builders days to get through it.

Rolfe.
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450-600mm are standard for loadbearing stone external walls. More than that is very unusual in 19th century residential properties.

And they'll have taken it through the roof as it's simply more convenient to remove large sections by crane. Partial downtaking of part of the external wall raises various challenges, not least possible impact on the surviving roof structure or the temporary propping.
 
It turns out the emergency services at the scene knew there were multiple fatalities from the moment they got there. I do not not know why exactly, but it has been very slow to get details out and as the Chief Constable announced one fatality it was known by the NHS there were eight. I wonder if scrapping the casualty bureau to save money is why this has not been the best run of incidents.

The reason why the copter is wrapped up is because the three bodies were still inside. The copter was holding up much of the building and the best recovery option was the slow one through the roof.
 
Rat said:
I'm surely not the only one who keeps wondering why the pub was named after an ancient one, before realizing that I've misread it.
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This is a thread for taking the tragedy of others personally, not making jokes!
 
Looking at the BBC photographs, the roof structure comprised traditional timber joists of around 150-200x50mm section at circa 450mm centres; this would be typical for a tenement floor and is not a great surprise. Sarking is either side modern sheeted board or alternatively traditional close boarding, although the latter visible might also be the boarding to support earlier ash plugging.

Such a structure will comfortably handle most credible loads, but would certainly not take a 3 tonne point loading even without impact damage to joist seatings.
 
commandlinegamer said:
How could that possibly be passed as airworthy? Surely that's grounds for a grounding until it's fixed?
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not necessarily. There is an entire framework surrounding most "for hire" aircraft that outlines airworthy and unairworthy. The grey area for many operators is defined in a document called the MEL or Minimum Equipment List. These are items that when non functional...the aircraft could operate safely without...provided the crew heeds certain restrictions or takes some other action. IIRC this particular fuel gauge was already put on MEL. Each MEL is assigned a category and it is this category that defines the length of time this aircraft can operate with while having this broken thing. In most cases they are Cat C which is a 10 day reprieve. This system allows aircraft owners to get where they need to to fix the aircraft at the next opportunity. Or to continue operations while waiting for parts etc.

IIRC this gauge had been on MEL. The action the pilots where supposed to take was to manually determine fuel load by filling it before each flight. Problem with that is the only way to do it is to top off each time. Then you have an exact qty. There may be further restrictions about calculating fuel remaining and landing with a much wider safety margin etc.

In the case of this pilot I believe they had been operating this aircraft like this for so long they were surely not following the time restrictions on the MEL, probably gotten complacent regarding verifying fuel load etc. There are ways to "trick" an MEL.
If the pilot writes up the fuel gauge that is intermittent and they put it on MEL for 10 days but operations is trying to pinch pennies the following routinely happens:
Operations will put the aircraft in a down status for maintenance to work the fuel gauge. Operations may even inform Mx to not dig too deep right now because the MEL is still good for X number of days. If you cant find a simple fix after 8 hours of trying we will return the aircraft to service under the remaining time left for that MEL. Mx goes to work on this intermittent gauge and finds that it is actually working right now. Operations then says...well sign it off! Aircraft is returned to service with no discrepancies. Pilot comes in and flies the aircraft and after an hour of flight the fuel gauge ***** the bed again. He then writes up the intermittent fuel gauge for the 9th time and it is placed on a 10 day MEL. And the cycle continues until the pilots get so mad they threaten to quit or go to the FAA...lol.

This scenario happens at airports all over the US with operators on a budget. And occasionally smaller commuters. Almost never at places like Netjets or large commercial airlines like SouthWest.


What items are currently in this particular aircrafts logs will be of great concern to the investigators...if there are any.

Another thing they will look for....if they suspect a gearbox failure as others have said...gearboxes have something called "chip detectors". It is a small magnetic plug at the base of the gearbox oil sump. If the gearbox is beginning to show signs of premature wear...it will "make metal". That metal will be attracted to the magnet on the chip detector. Many chip detectors have an electrical circuit built in so that when metal sticks to the chip detector it completes a circuit and illuminates a "chip detect" annunciator in the cockpit. The pilot will then follow procedures in his emergency procedures manual regarding this warning. Even if the gearbox is smashed investigators may be able to tell quite a bit by looking at the chip detector and doing metallurgical analysis.

You havent lived until you are 120 miles out to sea in a helo and your main chip detector annunciator illuminates. Thats a quiet flight back to the first available landing spot.:boggled:
 
383LQ4SS said:
not necessarily. There is an entire framework surrounding most "for hire" aircraft that outlines airworthy and unairworthy. The grey area for many operators is defined in a document called the MEL or Minimum Equipment List. These are items that when non functional...the aircraft could operate safely without...provided the crew heeds certain restrictions or takes some other action. IIRC this particular fuel gauge was already put on MEL. Each MEL is assigned a category and it is this category that defines the length of time this aircraft can operate with while having this broken thing. In most cases they are Cat C which is a 10 day reprieve. This system allows aircraft owners to get where they need to to fix the aircraft at the next opportunity. Or to continue operations while waiting for parts etc.

IIRC this gauge had been on MEL. The action the pilots where supposed to take was to manually determine fuel load by filling it before each flight. Problem with that is the only way to do it is to top off each time. Then you have an exact qty. There may be further restrictions about calculating fuel remaining and landing with a much wider safety margin etc.

In the case of this pilot I believe they had been operating this aircraft like this for so long they were surely not following the time restrictions on the MEL, probably gotten complacent regarding verifying fuel load etc. There are ways to "trick" an MEL.
If the pilot writes up the fuel gauge that is intermittent and they put it on MEL for 10 days but operations is trying to pinch pennies the following routinely happens:
Operations will put the aircraft in a down status for maintenance to work the fuel gauge. Operations may even inform Mx to not dig too deep right now because the MEL is still good for X number of days. If you cant find a simple fix after 8 hours of trying we will return the aircraft to service under the remaining time left for that MEL. Mx goes to work on this intermittent gauge and finds that it is actually working right now. Operations then says...well sign it off! Aircraft is returned to service with no discrepancies. Pilot comes in and flies the aircraft and after an hour of flight the fuel gauge ***** the bed again. He then writes up the intermittent fuel gauge for the 9th time and it is placed on a 10 day MEL. And the cycle continues until the pilots get so mad they threaten to quit or go to the FAA...lol.

This scenario happens at airports all over the US with operators on a budget. And occasionally smaller commuters. Almost never at places like Netjets or large commercial airlines like SouthWest.


What items are currently in this particular aircrafts logs will be of great concern to the investigators...if there are any.

Another thing they will look for....if they suspect a gearbox failure as others have said...gearboxes have something called "chip detectors". It is a small magnetic plug at the base of the gearbox oil sump. If the gearbox is beginning to show signs of premature wear...it will "make metal". That metal will be attracted to the magnet on the chip detector. Many chip detectors have an electrical circuit built in so that when metal sticks to the chip detector it completes a circuit and illuminates a "chip detect" annunciator in the cockpit. The pilot will then follow procedures in his emergency procedures manual regarding this warning. Even if the gearbox is smashed investigators may be able to tell quite a bit by looking at the chip detector and doing metallurgical analysis.

You havent lived until you are 120 miles out to sea in a helo and your main chip detector annunciator illuminates. Thats a quiet flight back to the first available landing spot.:boggled:
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I've rebuilt and serviced manual and automatic automotive gearboxes (I hope never to have to rebuild another automatic!) and there's usually at least a little metal dust adhering to the magnet in the sump. Obviously a lot of metal dust - or metal chips - would signify varying degrees of damage to the gears, but in my experience even a small pile of fine metal dust is par for the course, especially in very new or very old boxes.

I'm wondering, therefore, whether the same might be true in helicopter gearboxes? Obviously the torques involved are much higher, so the safe operating envelope is probably much tighter. But would even a little metal dust on the magnet signify an impending serious problem? Or does the electrical circuit require a significant amount of metal dust - or even metal shards - to be present before the alarm is triggered?

(I'm just curious, that's all!)

As others have said, it's clearly far to early to make any well-reasoned call on what caused the Glasgow accident. But the reports of the eyewitnesses (notwithstanding the fact that they may be mistaken), the fashion of the hard landing, and the condition of the wreckage, might lead to an initial hypothesis that this was a main rotor failure. And if that's the case, then it's a powertrain problem (discounting a major bird strike for apparent lack of evidence of this). And if that's the case, then the most likely candidates - given that it's a twin-engine craft - are the gearbox or final drive, or even a fatigue shear of the main shaft.

Hopefully it won't take the AAIB and/or the manufacturer to issue an interim report. That hope is magnified if it was indeed mechanical failure, since the pilot's family and friends would want comfort as soon as possible that pilot error played no (or minimal) part.
 
"No further fatalities at the scene." Three or four people still critical in hospital though.

Rolfe.
 
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