Hopefully soon the technology will be small enough to have FDRs and CVRs fitted in all aircraft.

Agreed!
But it doesn't seem to fully explain the Level of compression:


Bild: crash_ec135_glasgow_reqsaz.jpg - abload.de


vs: (Picture from Wikipedia)

Bild: ec135_police_compwas8y.jpg - abload.de

It looks as if it might have crashed nose first at maybe somewhere around 30° Nose Down.

it's not about size, it's about cost.

Shy,
All I said was that given your scenario, the engines would still be running. Sorry if it seemed offensive in any way, the intent wasn't there.

The reason I think things need to be downloaded is that not all are familiar with type and would have a better understanding of what goes on.

For the 135 2's, in an 'emergency autorotation', ie 'trds drive failure in the hover' it requires that the twist grips are to turned to minimum. (This does not shut the engines down unless a button is pressed on each throttle). The engines aren't fully shut down, 'secured', until after landing.

Yes the Nr would decay as you say, however the engines are still running at a low rpm.

My point is that the engines were not running immediately post crash, when perhaps they should have been.

Agreed, however its not necessarily about the actual crash recorder, it's also about the means of collecting data from all the various parameters prior to sending to the recorder. That said, it is much easier with modern digital helicopters where much of the data already exists on a digital data bus somewhere. For these, there seems scant justification for not fitting a recorder.

Kicking Horse makes an excellent point; no conclusions can be drawn from the condition of the cabin area until account is taken of what the fire service would have had to do to extricate the crew.

Just saw news at 10. Aerial shot of the footprint of the impact and confirmation that it was truly vertical with absolutely no fwd spd witness marks.

I must say a very big thank you on behalf of just another joe public to the emergency services (especially the fire crews) for the hard and tiring efforts under extremely harrowing circumstances. Having had the pleasure of meeting and working alongside many such rescuers and life savers at numerous incidents in my career, it is a timely reminder that these people are normally first on scene and last off scene. They have to cope and keep a clear head and then go home to their friends and family and try to lead a normal life after what they have just seen. A big thank you.

TC, here, here on your thanks to the emergency services.
:D



Vertical descent, nothing detached in flight and no engines running, IMHO only 3 possibilities.

An aviation expert explained that aircraft weight was the deciding factor as to whether recorders had to be fitted, and the weight of the equipment was such that adding it to an aircraft like the EC135 would increase the weight so that it would fall within the weight range where the FDR and CVR became mandatory - a sort of reverse Catch 22 situation . . .

Roof construction
 

On the roof construction it is most probable of the three roofs the first layer would have been the original floor.Built in a period of cheap timber shipyards and many local sawmills in the area. There may have been extra beams to retain internal walls as well. Second roof would have been added after removal of second floor, but would leak after twenty years then the final roof added on top to fix the leaks. This almost survived the full crash impact and probably saved a few lives. The aircraft in no way had a controlled landing and damage is not due to the roof giving way.

BBC documentary on TV now:- BBC News - The Crash that Shook Scotland

It's based on the maximum allowed takeoff weight, not the empty weight with the equipment etc. so adding equipment doesn't make any difference.

Impact forces of a high vertical descent
 

For those who find it hard to appreciate the impact forces on passengers of a impact at a high rate of vertical descent, here is a report of an EC 130 on a photo shoot that spun from 220ft onto sand dunes in the Netherlands in 2010. Video images showed a near vertical descent.
4 of the 5 occupants were killed despite activation of energy absorbing seats the same (?) or similar to those in the EC 135.
The cabin remained largely intact, upright and there was no fire.
Eurocopter seats can apparently protect the passenger from up to a 14g impact, Eurocopter suggested the impact was 20g.


http://www.onderzoeksraad.nl/uploads...-ph-ecj-nl.pdf

Sorry, more responses with facts might be helpful.

Heliarctic #345 - Whether carbon fibre or composite, the rotor blade main spars are made up of many layers of c-f/composite ribbon, before being covered in a honeycomb shaped filler and then the c-f/composite outer shell, the only metal part being the outer 2/3rds of the leading edge. In any event, it all disintegrates when the blades stop under power - this has not happened here. In addition, both tail fin & tail boom are made of roughly (possibly exactly) the same materials, neither are metal.

Jugofpropwash #346 / 348 - EC135 has three fuel tanks, a main one containing transfer pumps (always on in flight, unless tank is empty) which feed the two supply tanks, one for each engine. As mentioned by others, these two tanks are different sizes such that, if you really haven't noticed the earlier captions, the right engine will flame out a minute or so before the left, the first event waking the pilot up to his previous lack of concentration - and I'm NOT intimating that this happened here.

Mitchaa #356 - I'm afraid I'm not aware of your figures, as they're incorrect in this case and ignore the reduction gears required in any turbine to get the rotor to operating speed. Facts below.
TM engine compressor (N1) rotates @ 54,117 rpm, the N2 (turbine) output shaft at 44,038 rpm, in the opposite direction and through the centre of the N1 shaft. This is reduced by the engine gearbox to 5900 rpm, give or take.
The main transmission reduces the input to a main shaft speed of 395 rpm, and a tail rotor output drive shaft speed of 5,000 rpm. PW engines are similar at 58,000 N1 & 39,000 N2, near as makes no difference.

Standard O/H #358 - All four blades were still attached - the safety concerns from 2012 have no bearing on this, as they relate to cracks in the MRH, already discussed. These are monitored/inspected after every single flight.

Cabby, TC & others - re fuel. With full tanks (normally very difficult in a Police aircraft due to equipment carried, but possible in a T2+) an endurance of about 2:15 should be possible at night, which should also give another 20+ mins before tanks dry. A night endurance would more likely be up to 2 hrs, again with 20 mins flex, although I'd imagine a machine covering most of Scotland will remove unnecessary kit at night, in order to maximise endurance.

chop/SAS #369 - depends on which way you look at it, but it's clockwise when viewed from below - which is how occupants normally see it!

iranu #370 - P&W engines, rather than TM, but similar principle. Output shaft is the triangular flange near the bottom. The missing item at the top with four pegs is where the starter/generator lives.

More lookout & others #388 (I think some of my numbers may have been affected by deletions?) - the issue of Vortex ring, whilst possible, is unlikely, certainly for Police pilots who regularly hover OGE for long periods, which could fairly easily find them in VR if not careful. Being mindful of this, any mildly experienced pilot in this role will be more than aware of the incipient VR stage and will have flown out of it before it develops fully.

Concur with those sentiments re Fire & other services. Those of us at a distance can pontificate & postulate at relative leisure. I don't envy the extremely unpleasant task that those teams have had in sorting this out so sensitively.

Yellowbird135 - did you read the previous posts to yours at all? I think we have established that if the aircraft dropped vertically as described by the eye witnesses and confirmed by Mr Miller, without the main rotor turning, as evidenced at the crash site impact damage, and with no evidence of rotational damage to the blades, that it can NOT be called an autorotation, therefore can we draw a line under the choice of emergency landing site theories...

There have been some much more useful observations and analysis posted by the more experienced pilots amongst us in the last 24 hours, which I think rules out much of the earlier speculation, and now leaves only a small number of possibilities as to the cause. I only hope the AAIB can determine the cause of this tragedy quickly so we can prevent any similar occurrence in future.

Zorba,

Looking at some of the photographs of the removal process....there appears to be two blades that were very badly damaged near the rotor head....showing lots of frayed fibers....while the other two blades appeared undamaged.

Any thoughts on that?

i suspect the two 'frayed' blades were damaged on the fall through the roof. i of course am only speculating.

@zorab64
My point exactly, they are remarkably intact, indicating that the rotor head must have come to a full or very near stop, before going through the ceiling.

@the_flying_cop
I believe you are right.
Having unfortunately seen spinning rotors come in contact with the ground, they mostly disintegrate.

G-CPTN

I was on a board with NTSB and AAIB in Washington where I proposed that the Part 27 helicopter weight cap exclude the weight for enhanced safety and data recording (recorders, bird strike,etc) as long as performance is met and the souls on board was within Part 27. It was rejected. The AAIB rep even lamented the lack of recorders on lights but voted no.

Going from 7000 to 7001 lbs causes many new design rules to kick in which, while great, should not prohibit a free pass on weight increases above Part 27 caused by safety related improvements.

Maybe that earlier decision will now be revisited.

@Sultan

So... The Bell 429 case to FAA and EASA... If they ever decide to rule on it again.