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Police helicopter crashes onto Glasgow pub

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Police helicopter crashes onto Glasgow pub

Old 2nd Dec 2013, 13:38
  #321 (permalink)  
 
Join Date: Mar 2008
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Looking at the bbc video of the hole in the roof the first layer could not support a 3 ton aircraft even if there was no impact at all so this first layer may have been the first bang heard by the occupants of the bar as the AC penetrated it.
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Old 2nd Dec 2013, 13:41
  #322 (permalink)  
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Glasgow: No Mayday Ahead Of Helicopter Crash
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Old 2nd Dec 2013, 13:46
  #323 (permalink)  
 
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Eyewitness statements

I can't comment on the Accident as I'm no expert. What I can comment are Witness statements.

I worked for over 25 years in Aviation Insurance, regularly liasing with our Claims Department. On numerous occasions the discussion came up about what witnesses to an Accident acctually saw. On nearly every occasion the Claims department came across was that the Witness statements were at best incorrect, at worst completely invalid. Time and time again what the witness saw, and what actually happened was a completely different scenario.

Witness 1 The port engine was one fire prior to the crash.

Witness 2 The starboard engine was on fire prior to the crash.

Witness 3 There was no fire prior to the crash.

So what I'm basically saying, is you can discount all witness statements, unless the Accident investigators prove otherwise!
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Old 2nd Dec 2013, 13:55
  #324 (permalink)  
 
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Statement just made to the media that the cause was not associated in any way with previous incidents involving this type.
And who made that statement?
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Old 2nd Dec 2013, 13:56
  #325 (permalink)  
 
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So much reading and, sadly, so much rubbish to filter. Herewith a little clarification I hope, at least that's what's intended. Some comments have been made / questions asked by more than one poster.

Skyshout is not part of considered options in any real emergency - identify the problem, react to the problem with the appropriate actions but, foremost, fly the aircraft.

Using the camera or downlink does not mean the recorder is recording. They are three different, but connected systems. Daylight or thermal image camera is used & viewed on aircraft screens; intercom and up to four relevant Police radio transmissions can be selectively recorded if necessary for evidence; and/or downlinked if it might be useful to a control room. As already mentioned, Police aircraft are not fitted with "black boxes".

Misformonkey (#190) - no, there is no penalty for OGE hovering so long as it's flown within the normal aircraft limits, as it should be at all times. The only problem is the tail boom, which needs more regular cleaning due to the exhaust gasses.

Helilog56 (#218) Whitehead06 has more experience in this field than almost anyone in UK Police Air Support - don't.

Redhill Phill, tartare #304 & others - I think the post using the bicycle analogy has been the simplest. The item in question is called a "freewheel", and there are two in the combiner gearbox, one for each engine, such that if an engine loses power, it stops driving. If you enter a practice autorotation, the blades rotate faster than the engines & the freewheels allow the engines to a "flight idle", ready to re-engage as soon as the rotor speed drops, due to collective input.
Looking at the recovery video, my earlier assertion that the engines were not driving the rotors at time of impact would seem not far off the mark. Two full blades have been cut off post accident, the other two broken at the root weak point when they were stopped or broken by the ground structure - you can see the delaminated carbon fibre main spars at the end of the control cuffs.

Pilot DAR #257- you hypothesise correctly in principle - i.e. using as much rotor inertia as possible in the flare & final stages is exactly what you want to minimise impact forces but, when it's all over, there'll be no lift & the full weight of the aircraft will rest on whatever's touching terra firma.

mjb #268 - once an engine is alight, it tends to stay that way. The ignitors do not operate once they've done their job & got a flame going and, in any case, make no significant noise over the noise of the aircraft if there'd been a flame-out, for instance, and they were try to re-light.

vaquearoareo #291 - NVG are not widely used in UK Police aviation. There's some pretty good kit that does a similar job and NVG has greatest validity when operating close to the ground, which is not how the aircraft are operated most of the time, since they are better able to support the ground officers with the advantage of 1000'+ operating altitude - it's also less annoying for the law-abiding majority!

The recovery video speaks volumes to those who know the airframe. For those that normally sit in the cabin, it's very sobering. The blade roots, I've mentioned (as have others since I started typing!). The missing port skid, and damaged starboard one (see flotation bag at the rear) may show the initial landing was mostly right way up, if heavy. The fact that the tail-boom appears intact up to the joint with the fin is also interesting, although my earlier thoughts that the aircraft landed & then rolled left into the pub when the roof collapsed may appear from a confusion between photos taken from different ends of the site, although it still it may be that the cabin damage was caused post impact. It's also possible that the first thing to hit hard was the tail itself - not always surprising with a high nose-up decellerative attitude if in auto - even though there would seem to have been some "twist" involved around the tail-fin area, and not much separation with forward speed?

It remains an entirely tragic event but, as with others that have caused heated debate amongst professionals, journos & others (e.g. Gazelle -Honnister accident), it was the professionals who read things straight. This one is a lot more confusing, but for those who continue to do this job (and especially in this aircraft type) it is most important to try & understand what might have happened so that they can remain assured their machine will not leave them in the lurch. I remain confident that this is one of the best helicopters in the world for the job but, as with every accident & incident, this forum allows open thought and reassurance for many others. We've had a fantastic record of safe operations in this country, specifically in Police aviation, but the AAIB & industry experts will find the answers in due course.

Last edited by Jetdriver; 3rd Dec 2013 at 13:43.
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Old 2nd Dec 2013, 14:00
  #326 (permalink)  
 
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FTE Pruner

I'm amazed that so many here apparently take seriously the idea of a healthy landing followed by a crew-fatal 15ft roof collapse which was not even free-fall. Being underneath a collapsed roof and a helicopter: a grievous situation. Being inside an impact-engineered crew compartment which slumps through a partially-intact low flat roof: I just don't buy that as a prime candidate for what led to this terrible outcome for the crew.

Is there a structural engineer here with expertise regarding the degree to which a frangible surface such as an elderly pub roof may not do the catastrophic damage to an airframe that hitting rock, clay or concrete would, despite still causing crushing deformation and very significant Gs (as regards survivability)? There's a lot of room for catastrophe in the zone between controlled autorotation on the one hand and streamlined terminal velocity on the other.
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Old 2nd Dec 2013, 14:04
  #327 (permalink)  
 
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Whitefriars, on the subject of insurance who will pay out on this one? Does the civilian helicopter contract company provide third party insurance, or is it the police or is it the Scottish/Home Office i.e. the tax payer "self-insuring"?

If a critical component failure was to blame could all this liability rest with Eurocopter? Either way, the potential claim could run into millions of 's.

Last edited by Madbob; 2nd Dec 2013 at 14:34.
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Old 2nd Dec 2013, 14:05
  #328 (permalink)  
 
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SAS's pic shows one of the building's aircon units (behind the tail) pushed sideways off it's fitting. Look at the other unit on the right and compare the feed pipe to see how it has been moved.

The picture also shows a masonry wall at the back of the hole the helicopter fell through.

Perhaps the helicopter landed flat on the roof with a little bit of yaw causing the tail boom to strike the aircon unit, and with an unsupported roof at the front of the thin skids the machine fell through it nose first.

Only those currently investigating the scene are closer to the truth to what actually happened.
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Old 2nd Dec 2013, 14:07
  #329 (permalink)  
 
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David Miller, deputy chief inspector of the Air Accidents Investigation Branch (AAIB), said the helicopter made a vertical descent into the Clutha bar in Glasgow and he confirmed the pilot made no mayday call.
The helicopter did not have a flight data recorder
It did, however, have electronic systems on board which may have important recorded data
Nothing detached from the craft in flight before the accident
And there is nothing to connect the incident with any previous accidents in the North Sea
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Old 2nd Dec 2013, 14:08
  #330 (permalink)  
 
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Insurance

All Police aircraft are insured commercially, unlike the military.
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Old 2nd Dec 2013, 14:09
  #331 (permalink)  
 
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EC135 Hard Landing

https://www.google.es/search?q=ec135...2F%3B800%3B400
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Old 2nd Dec 2013, 14:13
  #332 (permalink)  
 
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I've been flying for a few decades now. Part helicopter, part fixed wing. I have flown police helicopters, and have suffered a sudden engine failure in a low-ish hover, at night over a very major city centre.

The one thing that seems pretty obvious from today's pictures is that this wasn't a 'crash' per-se. As others have suggested it seems like a pretty superb attempt at a forced landing. The cause of the aircraft's rapid, and undoubtedly involuntary descent is likely to remain the subject of speculation for some time yet. But the fact remains, this aircraft was 'landed', albeit in the most difficult circumstances it is possible to imagine.

Every bone in my body strongly suggests that this pilot did the most fantastic job in those crucial seconds. Tragically, he and others were dreadfully, dreadfully unlucky.

Such a great shame. I'll offer a toast tonight.
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Old 2nd Dec 2013, 14:16
  #333 (permalink)  
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Originally Posted by skadi
And who made that statement?
Didn't catch the name - I heard it on BBCR5.
And there is nothing to connect the incident with any previous accidents in the North Sea
That could have been what I heard and attributed it to "previous incidents involving this type".
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Old 2nd Dec 2013, 14:31
  #334 (permalink)  
 
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Here is some information for those wishing to know a bit more of the EC135:

http://www.easa.europa.eu/certificat...y-23072012.pdf

What strikes me is the rotor blades being remarkably intact, along that with the tail boom.
Some here keep referring to the main rotorblades as being carbon fiber, they are not, they are fiber composite materials, there is a difference.
The picture in post "202" of the fire crew carrying the blade shows practically no damage at all, to neither leading edge or trailing edge for that matter.

Also visible in the picture is the tail rotor driveshaft still attached to the fenestron/blades. Whilst the vertical stabilizer/shroud seems to have been destroyed, maybe in the flare? The whole vertical stabilizer assy, is also made of fiberglass composites unlike the tail boom, and is indeed a very light piece.

In a full auto, engines at idle upon landing, how long would it take the rotor head to come to a standstill if the rotor brake was engaged immediately upon landing on an EC135?
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Old 2nd Dec 2013, 14:37
  #335 (permalink)  
 
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Question - from reading the posts here, it appears the helicopter has two separate fuel tanks? If so, I'm assuming that if the fuel was contaminated, the two engines would be less likely to be affected at the same exact time, which would effectively rule fuel contamination out as a cause. Correct?

Second - this is a real long shot, but. . . If the craft was flying at a low level, is there any way they could have woken/startled a flock of birds which were nesting for the night, with the birds then taking off in mass and being ingested? Could that have caused a sudden double engine failure?
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Old 2nd Dec 2013, 14:39
  #336 (permalink)  
 
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Better view of the damage...
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Old 2nd Dec 2013, 14:39
  #337 (permalink)  
 
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Gentlemen, for those that look at my profile, you'll realise that I am a long time lurker on here, and I simply cannot remember if or when I have ever posted on PPRuNe, but feel compelled to do so to try to offer some idea as to what the crew may have been facing during the incident. To put it into context, I have considerable military RW flying experience in a variety of aircraft, but have no experience of Police Flying or the EC in question. I have been instructing on RW for 14 years.

Any malfunction that occurs in a relatively complex aircraft can result in a tragic loss of life, and it need not necessarily be a catastrophic failure. Some factors to consider here, IMO, are:

Night Operations - forgive me, but I think it needs re-iterating that malfunction handling at night is a complex business. The fundamental aspect of flying, particulalry RW when close to the ground, is the utilisation of visual references in order to judge required control inputs which will make the aircraft go where you want it to. Take away visual references and it become a very difficult thing to achieve (ask anyone who tries to hover over the sea - even daytime, or those that land on ships at night for a living). The point being that DTs task was immense in a) recognising the emergency b) reacting to it and c) attempting to identify a clear area in a busy urban environment. All this against a backdrop of, potentially, losing height (which really doesn't take long from 1000ft (if that's where they started from) when you bear in mind that in stable autorotation a medium weight helo will experience approx 1500-2000ft/min rate of descent. That would, and I'm generalising here because I do not know the height from which this emergency was initiated, give him between 30 and 45 seconds to identify a suitable area whilst dealing with an emergency. Not being on NVG would have further limited his choice of area to best guess - a flat, clear area, probably having to rely on the Radalt to judge height (which is of course giving intermittent readouts as the aircraft flew over buildings)

Also worth bearing in mind is that malfunctions often occur in a gradual manner. They may have been flying along and been alerted to a developing situation. This may have steered them toward a particular course of action (ie positioning the aircraft into wind - vital - and preparing to make an emergency power on approach. This would inevitably have meant initiating a descent, which would of course have then, ironically, have limited their options if the circumstances worsened resulting in an engines off landing.

Truth be known, there isn't a pilot in the world that deals with a malfunction the same way, the reason being that we all deal with high pressure scenarios in a different fashion. I have no answers as to what happened, but I can however appreciate the awful sense of diminishing options that the crew may have faced. A shocking accident that only serves to remind us of how fragile we all are.
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Old 2nd Dec 2013, 14:45
  #338 (permalink)  
 
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Left hand skid is not missing as some have posted, it's severely bent upwards.
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Old 2nd Dec 2013, 14:52
  #339 (permalink)  
 
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Looking at the roof in the video, I'm going to speculate.

This was a successful autorotative forced landing. At the last second the pilot realised he was coming into a roof and not the ground, and flared and pulled hard to get a few feet of height. With nose high and NR low the tail boom impacted first - note the small hole in the roof to the south of the big one - which damaged the the fenestron area, then the aircraft ran on its skids for about 20 feet, trashing the aircon unit on the roof as it went (loook at the trackmarks on the roof) which did some damage to the underside, before the roof collapsed under the increasing weight as the last of the Nr vanished, the aircraft tipped sharply nosedown and with at a guess about 20kts forward speed smacked hard into the end wall. That is not a type of impact that aircraft are designed to resist.
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Old 2nd Dec 2013, 14:56
  #340 (permalink)  
 
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As i said way back at the start The AAIB will be quick to release any findings especially if this is not a one off so lets leave it to the proffessional investigation team

What i would say in regards to some suggestions is that i am up here working and the Clutha has 3 timber roofs made up of original first floor with substantial beams soundproofing secondary roof and further roof over that

It was a converted 3 floor tennament building with metre thick walls
This may well explain the delayed penetration after the initial very hard impact through the main roof structure

There is no way a 3 ton heli would penetrate the structure by 1 G alone
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