SASless,

No, they're on the collective. A previous post pointed out that they bring the engines back to idle and a separate switch has to be made to shut down the engines.

The rotor brake is at the top of the windshield pillar, however. :hmm:

http://www.vtol.org/images/dmGallery...135%20T2_1.jpg

It is after all a pp RUMOUR ne. People need to get off their high horses.

TC, do you recall our discussions here on short (high speed) shaft failure? Not sure if this machine uses the 355 setup, I got a feeling it has the two inputs into the MGB, perhaps someone can confirm. If it was an unfortunate case of 2 x unlucky with the short shaft then it would take a few seconds longer to identify this kind of failure as the NR speed dropped and the NGs ran away.

Sawman, thanks for you informative post. Can you postulate any ideas on how this roof was attached to the front wall of this building as that is the bit of the roof that seems to have been pulled out/off its supports first, probably through initial bending of the beams.

I thought I read where one witness said it flew over "that low you could almost touch it",and it was making metallic crunching noises.Then he saw sparks fly everywhere like fireworks had gone off,before it disappeared from his view.

There is a certain amount of arrogance by some posters, and daft ideas by others, but some interesting points of view.

I am a frequent visitor to the site, but infrequent poster. My youngest son wants to be a pilot and is mid-application to join the navy to train as a helicopter pilot and I usually read the wannabe section and military threads. I spotted this thread and have read it with considerable interest as my middle son is the editor of the Scottish Sun who witnessed the fall of the helicopter on Friday night from the top floor of the multistorey car park, about 250metres West from the crash site. Despite his journalistic background and being a hardened hack, he has been severely traumatised by what he saw. Gordon's reports have been well published on all of the TV channels and newspapers but I think it is fair to say that he believes that the helicopter was out of control. He was on the phone to a colleague in London and was about to get his the car to drive home when he became aware of a loud noise above him - when Gordon is on the phone, like many young people, it is difficult to distract him so the noise must have been considerable. He describes the night as being crystal clear and was aware of the helicopter starting its fall. He initially thought the helicopter was falling towards him and dived behind the car but continued to watch the helicopter fall. He describes the helicopter tumbling - not sure if this is what you are describing as autorotating - but he does not think that this was controlled. The helicopter, as we know, did not hit the car park but landed 250m away on the other side of a block of flats and the Holiday Inn Express and he did not see the impact. He was able to see the police signs on the helicopter as it came down and stated that he was 80% certain that it was the police helicopter that had been involved long before it was officially announced. He is also clear that the helicopter was eerily quiet, that the rotors did not seem to be rotating and was amazed that there was no explosion. He struggled to get his car out of the car park and by the time he got to the site on foot, which is not far away, the emergency services were already arriving and blocking off the scene. He ran round the corner into Argyll Street to get back to his office in Queen Street. He spoke to a policeman in Argyll Street who was totally unaware of the helicopter coming down and initially did not believe him until he called into control.

I appreciate that Gordon is no expert but he is clear that the helicopter could not have landed gently on the roof of the pub, or that the pilot was trying to find a safe landing place. He has been interviewed by the authorities and told that in due course will be required to give evidence at any subsequent Fatal Accident Inquiry.

I hope that this helps and that the reason for the crash is ascertained sooner rather than later.

Maybe someone can tell me.

Do these things still have a " Jesus nut " ?

SAS,

You may be right. I do not remember the presentation I saw, but either the 135 or 145 engine controls are routed from the cockpit to the engines via the windshields center frame. This design would be equal to or worse than the S-76 design as the S-76 had contributing significant wear in the locking gates, while routing controls in bird strike areas would be a fundamental design flaw.

The Sultan

Just to throw a couple of points in here to answer some of the observer related questions. I have not worked at this particular unit, but can offer some general comments.

The majority of observers I have met over my years were not particularly aviation minded. In this i mean, they obviously loved being in the air, but did not have a burning desire to be at the controls. Indeed in my unit, it was actively discouraged. I can remember my former boss clearly stating during the selection and training process that pilots are there to do the flying and the observers were there to observe what was happening on the ground.

Obviously, this could never be a hard and fast rule, and with mandatory CRM training and so forth, as crews evolved into close knit teams, the pilots could not help but get involved in the police work, and some observers assisted with some aspects of the flying. When I say assist, im talking in terms of pointing out hazards such as powerlines, birds, other traffic etc, missed radio calls from ATC and so on, not the actual hands on stuff. Dual controls were only fitted during periods of pilot training such as LPC's and OPC's.

I have always been fascinated with aviation and joined the police with the sole intention of getting onto the Air Support Unit. I have been a PPL holder and have always had an unhealthy attraction to the flying side of things in addition to doing my observing. So I have a little knowledge in both camps if you will.

As mentioned above, the nightsun is powered only when the mission bus is on, and power is coming from both generators. Perhaps i can answer a couple of points here.

I always found the nightsun to be more of a burden than an aid. It was never pointing in the right position when you needed it, and took an age to get it pointing where you actually needed it. Trying to slave it to the camera was nigh on impossible. This was under a normal workload. You would probably be looking in the area of a minute maybe more to get it to point where you wanted.

I notice that on library images of G-SPAO the nightsun is mounted at the front and is forward facing, but even so, it would still take valueable time to position.

More importantly, it was never to be operated at less than 500' AGL due to the possibility of someone on the ground being blinded or distracted by it.

I have tried to put myself in the position of the crew on that fateful night, and through all the scenarios i have envisaged using the infomation posted here and in the media, i cannot think of one where i would have considered the use of the nightsun as a landing aid in the circumstances the crew were faced with on that night. the only time it would have ever been considered would be if we had needed to conduct an ad hoc landing at night. even at the best of times, these landings present many dangers.

As mentioned before, the intercom is not routinely recorded, just the radio traffic between the crew and the ground.

Downlink is not routinely used. On the 135 the aerial is stowed horizontally and is motored down for use and back up for landing. If they were en route back to the unit, chances are this would have been stowed as per the approach checks.

The camera is always recording, however, it is standard practice during take off and landing to have it stowed, facing rear. This reduces the risk of the lens being damaged by FOD and also means less cleaning squashed flies off.

I have some questions of my own if i may, and please forgive any lack of technical knowledge.

Birdstrike?

Birdstrikes have been mentioned several times on the thread, but I am struggling with how this could have been the case. From what has been presented so far, the suggestion is that the aircraft had very little, if any, horizontal speed. Additionally, I have not experienced or know of much bird activity at around 700' AGL at night. Am i correct in thinking that if a bird came into the vicinity of a hovering helicopter, the only real damage could be through ingestion into the engines? If it flew towards the cabin, would the downwash not push it away? Similarly, if it got into the disc area, surely it would be shredded and not cause an issue? If by some miracle it hit the cabin intact, it would surely not be capable of causing any damage, just like a bird flying into your kitchen window?

Tumbling?

Witness accounts have suggested the aircraft tumbled through the air end to end. Can someone explain how this could be possible, even more so if the engines were off. I would have thought that any violent departure would have been a very noisy affair, directly contrasting the serenity that has been described. Other than a huge cyclic input, what might cause this?

Rotors

I still cannot fathom how the pictures of the MR blades show so little damage. And if the aircraft did fall with rotors stopped, how could this possibly happen. I understand the concept of auto rotation, and NR decay, but to actually have them stop whilst in the air, is this possible?

Mechanical failure.

I have a rough understanding of how the transmissions work, but tying in with the rotor question, if the MGB failed, would this cause the rotors to stop, or just go into freewheeling. I am probably way off the mark here, but I understood it to be that if the blades stopped then the cabin would rotate in the opposite direction. Similarly, if the tail rotor failed, am i right in thinking that the cabin would spin the opposite way to the MR? Looking at the impact, it is apparent that there was no cabin rotation going on. I am curious why there was no grounding of the fleet straight after. As some have suggested, this could mean that the AAIB are fully aware of the cause, but are waiting for some confirmation before releasing any details.

I have so many questions, and I am grateful for the insight that many of you have provided on the thread thus far. It is always a tricky thing to discuss as we are all obviously devastated at the loss, but being part of the rotary family we are all desperate for information and answers. Time will hopefully reveal all. My gut feeling at this time is that they managed to land on the roof and were then dealt the cruellest of blows as the roof collapsed.


Edit: partially deleted.

Fuel failure theory
 

You may be interested in this if you have not already seen it?

Glasgow helicopter tragedy: Fuel failure theory to be examined as probe begins into why chopper dropped like a stone from the sky - Daily Record

lets assume for a minute that they did hit that roof not distinctly nose down but rather somewhat level.
that this initially resulted in something remotely comparable to that dutch 130, to some degree weakened or even disintegrated around the wind screen area. already missing the boom. sitting on top of that roof that moment before it gave away.
that wreck falling through the ceiling down another maybe 10ft, arriving almost vertically.
for me thats maybe somewhere in the neighborhood of a possibility to reconcile some of the obvious contradictions. would at least explain the shape of that pile they craned out in the end, also a few of the ideas on this thread. maybe even the condition of the blades?

First let me clarify that based on the pics I saw, the upper roof was constructed with bar joists, also called "Open Web Steel Joists", and not RSJ's (aka I-Beams) as others have implied. Here's a link to a pic of a bar joist:
Google Image Result for http://www.newmill.com/images/standard_steeljoist.gif

The ends of two of these where they sheared are clearly visible in the removal pics, but at a glance could be mistaken for RSJ's. I had to look closely myself to be absolutely sure, because the use of RSJ's in building such a roof would have been huge engineering overkill and I've never seen this type of roof done that way. Bar joists are lighter, cheaper, and totally sufficient. Some RSJ's can be integrated into this type of roof to carry heavy loads from above, but I saw nothing more than some relatively light HVAC equipment up there which would not require this. Had these been RSJ's and not bar joists they would have held a roof full of limousines, and certainly this single machine dropping at any free-fall speed it could have reached with it landing across several of them. Now we've got that cleared up, here's your answer:

Bar joists may be supported by any relatively flat surface capable of carrying their load. They can be set atop a wall or beam, on a sufficient ledge, into a pocket created for them in a masonry wall (one end only), or welded to an angled or flat plate which is attached to the structure. In a roof-over with masonary walls capable of the loading, the most common technique is to use 'angle iron' ledges, usually around 50mm each side, running along the entire length of the wall or nearly so. With most bar joists, only the top chord extends to the wall, the internal bracing transferring the load to it geometrically at the ends. Some, however, have both the upper and lower chords spanning the full distance- these will use a duplicate of the upper chord mounting technique at the bottom. Not a lot of difference in strength with either one.

Since there is not normally expected to be much tensile loading, ie 'pulling away', but only vertical carrying of weight involved, the method of attachment does not require much pull-out strength but is designed to carry a vertical shearing force instead. Attaching the ledge can be done many ways: through-bolts spanning the wall, masonary anchors into the wall, and in new construction plates set into the wall (which can be used alone). Being an existing structure, the most likely is one of the first two mentioned. Normally this connection is welded, more to prevent horizontal movement and uplift than anything else, so that is often not a full weld, but something closer to a heavy tack-weld. Good practice says to weld both sides but this is not always done, nor is it normally necessary.

In this case the welds could have failed under unexpected stress, or the anchoring system for what the bar joists were attached to could have failed, or the combination of these two. If it was individual connection plates, the connection to the wall is the most likely failure point. If it was and 'angle iron' ledge with through-bolts, it could have sheared as it deformed with only sections pulling away from the wall and the rest staying intact. This could have coincided with the ledges pulling over the head of these bolts. I saw no evidence of through-bolts in any pics-they would have been visible outside on the front wall face. The joist itself could have sheared from tensile necking but that's rather unlikely, or at could have received a 'cutting' type influence form another object, again unlikely. Not being able to see in any pics I've found, my best guess is that some form of masonry anchor was used and it pulled out of the wall with the ledge. Whatever the type of failure, it was all probably constructed to good standard since that's very easy to do, it just wasn't designed to be loaded in the way it was.

It seems that a couple folks here may have directly seen this part of how the Clutha was constructed and if so I'd like them to PM me so that we can discuss this off-thread and I can learn more.

SASless

The S-76 was doing 145 knots, this one was doing zero knots. I am not quite sure of the relationship? Bird strikes usually leave obvious bits of bird lying around.

I was in two minds whether to post, but since this tragic accident happened so close to the 10th anniversary of another which I feel shares some common features, on balance I felt it apposite. If anyone feels different then please ask me or a mod to delete or edit this post as appropriate. I make no apology if I come across as sentimental.

G-XCEL crashed in December 2003, killing 3 people. In this case and G-XCEL's, a helicopter with a pretty good safety record crashed suddenly, with no chance for the crew to get out a distress call. The pilots in both cases were experienced, professional and regarded by their peers as such. In G-XCEL's case a mechanical fault which those onboard could not have foreseen nor dealt with in the time and height available killed them.

My only hope is that - odd though it may seem - that in this case the same is found to be true.

Godspeed to the three killed in G-SPAO and the six killed on the ground last Friday, and remembering Ian, James and Gordon.

No, they don't

Neither in the EC 145 or EC 135 the enginecontrols are routed through the centerframe. But the EC145 has flexballcables for the flightcontrols routed through the windshield centerframe.

skadi

Nr Fairy

G-XCEL was indeed very tragic. However there is no similarity here really - in that case the cause was a failing freewheel in the combiner gearbox and the ensuing vibrations broke the acft up in flight, leaving debris spread over a fairly wide area. G-SPAO was intact on impact.

rotorspeed:

Thanks for your input - I'd not considered beyond those parallels I had listed, and was more reminded that a major mechanical failure overwhelmed a pilot as experienced and professional as Ian. I'm no accident investigator nor do I wish to speculate, but something of that ilk is top of my own internal list, well above other possible causes.

Scoobydroo#534 writes the editor of the Scottish Sun was on his phone when he heard the helicopter in trouble. I am not sure if reading between the lines that means he managed to record some of the descent, so the authorities had some idea what happened right away.

If the pilot had some power ("engine making noises") he would have been aiming for a better space than an intersection.

(1) If you have some power to make a controlled descent, but that is lost at say 300ft agl, would you be able to initiate autorotation?

(2) Is the ATC record from the transponder as accurate as a record from an on-board GPS? I am wondering if the description "vertical" would still allow a significant horizontal vector.

Police helicopter crashes onto Glasgow pub
 

While it is conceivable that an engine flameout could have been caused by ingestion or blocking of intakes by a flock/ murmuration of starlings ( they sometimes roost in the city, often on cold clear nights and I have witness murmuration of large numbers in the vicinity of the rail bridge leading to central station ( east of the crash site)
A flameout / bird strike might explain the coughing/ spluttering noise reported by one eye witness or the sparks by another. However, an autorotation to recovery would be second nature for the PIC.
The bird strike theory doesn't explain the rate I'd descent nor loss of control.
A murmuration of starlings can include several thousand birds acting as if it is a single entity flitting rapidly around the sky.
I have encountered occasional multiple bird strike ( flock of starlings?) on departure from EGPH often between 400-800ft. Usually just a few thunks and thankfully nothing through the fans!