Cabby, we'll all look forward to it but I sense we'll need to manage our expectations, as I can't imagine it will be too meaty given the relatively short time in which it may be produced.

lynx
 

Fly for fun
Was on lynx at the time and that was the armiture winding that failed and the blade came off seems the blades were still attached in this case

Damage
 

We can hopefully assume the AAIB will conduct the investigation with the help of structural engineers with regards to damage to the bar?

That thought crossed my mind too, and by the time the true nature of the dark rectangle became clear, there would be no time to alter the flightpath even if any control was still available.

Ornis - I was just offering opinion on the reasons why a mass grounding was unlikely, given the number of machines flying safely & the lack of other related incidents. I tend to deal in what I know and can deduce from photos, as eye-witness reports may be valuable to the AAIB, but they're generally a little instant on a thread like this, so best treated with a pinch of salt.

As others have intimated, I feel it unlikely that this aircraft came down vertically, from significant height, with rotors stopped. It is possible that the rotors were almost stationary in the very final stages, after most of the energy had been dissipated in any flare or cushioning, since there is neither any apparent rotational damage to main or tail rotor blades. In addition, it would be a surprise if a near vertical, rotors-stopped, impact from anything over about 50' would result in as little damage to the airframe. "Little" is sadly relative, of course.

Others have mentioned coning angle - the 135 has such stiff blades that there is almost no coning angle.

Another small point to note is this was probably a 2.5 tonne weight when it came to rest = 2910 MAUW less 400kg fuel for 2 hrs flight.

Some of the information from professional pilots with more experience than I do has been very interesting and impressive. Some like zorab64 have a great way of articulating the information. Thanks for this.

A question for the experts:

I'd originally been thinking along the lines of a forgiving roof structure meeting with a good auto at about 10 feet before expected.

However, seeing the damage to the aircraft and roof together with the lack of rotor damage has made me think that's not right.

The impact energy looks to be somewhere between a heavy auto and a freefall from a significant height. Is it possible that the following factors prevented successful autorotation with the result that there wasn't enough inertia when the power was pulled in and the rotor system stopped?

- Auto commenced at low height
- Minimal airspeed
- Very little wind
- Low inertia rotor system
- Aircraft very light as low on fuel at this stage of mission

Is that feasible? Apologies if I'm talking nonsense.

Airframe
 

Having seen pictures of the airframe and cabin I'm so shocked that all three on board were killed, I do understand there will be more compounding problems but have seen people walk away from more damaged machines?

G ndlr
 

Anyone know the reg? Just drove past a heli wreck on the m6, uncovered with above reg. What a mess, horrible to see and brings it home

Mesh, check your PMs.

Street Lighting
 

There certainly does appear to be many conflicts of evidence, primarily the lack rotor damage which suggests little to no rotation on their impact with the pub roof. Yet the less-than-expected damage to both pub and aircraft suggest that the descent was in some way under a degree of control. Eye witnesses have stated that the main rotor was barely moving which would preclude an autorotation.

I have a home workshop and know the dangers of discharge lighting in such a setting. At certain speeds , rotational equipment such as lathes and drills can appear stationary when in operation – potentially very dangerous – any why I use only conventional incandescent bulbs.

In the modern street environment there is much use of high intensity discharge lighting. Could it be that the eye witnesses were deceived and there was indeed significant rotation prior to impact with a resultant degree of control – it was just hidden by the 50Hz lighting?

presumably all the street lights would have to be in identical phase for that to happen eko

Unfortunately the damage pattern does seem to match quite well to a decent with little to no RRPM:

Nose low (Damage pattern of cabin), Retreating Blade side first (left side skid bent up and airframe damaged more than right side of Helicopter) impact with quite significant energy, Rotorblades + Fenestron showing almost no signs of rotation upon impact.
If you compare the cabin to the one of the Netherlands EC130 mentioned a few Posts earlier which impacted solid ground at 1800 ft/min (>20g) and looking at the cabin in this instance after having impacted a much softer strúcture I'm afraid it came down quite rapidly (pretty sure >2000 ft/min) with very little rotor energy.
For whatever reason.

Point taken, SASless. But it appears something has been agreed by the 'powers' that no fleet check has been considered necessary.

Whitehead06. Increased coning angle due to a lack of Nr.

Dictus. The lynx reference was just to illustrate that if a catastrophic issue inherent in the aircraft would these days be publicised as soon as known.

My thought too, see post #138.

Fly for fun:And therefore reduced CF ... am I following your line of thought correctly?

I'm looking at a poster who on an earlier page complains that there are too many other posters complaining we shouldn't be hypothocating about such a delicate issue on a rumour network and then off he goes branding someone els for coming out with a hypothetical suggestion about fuel starvation??? Sort your life out sunshine.

The jib of the crane lifting the wreckage has a camera on it. This is normal for heavy haulage companies so that the cab driver can monitor his progress. This is what was used on the news last night. It shows the cab dove vertically into the roof top. There was categorically NO evidence of horizontal flight. It "appears" as if the cab went in at a steep nose down attitude (>20 degrees). The entire lower half of the cabin area was flattened. Totally non survivable. Enough said.
Every picture and all videos of the salvage reclamation work that I have seen shows each of the rotor blades to be (relatively) intact. They certainly did not exhibit serious blunt force trauma.
In fact with the exception of one of the root sections showing scarring - the blades were relatively unscathed. The fenestron was intact.
Now assuming one agrees with that statement, what could lead to that?

Assuming the cab was at or around 700' (anyone disagree?), it means the blades stopped within that distance or putting it bluntly, with the a/c even partially under control, the blades stopped rotating during the 30 seconds it took to fall out of the sky.
How could the rotor go from nominal governed Nr of >300 RPM to zero in 30 seconds? 700 feet in the hover to ground level.

1. Fuel starvation to both engines and pilot does absolutely nothing with collective in the hover. Very unlikely.
2 Tail rotor failure - non starter - no rotational witness marks on impact.
3. Pilot incapacitated but collective remains at a high power setting - very unlikely.
4. Sun and planetary gears gears break up, disconnecting the MRH from the engines. Rotors and tail fenestron slow down, a/c descends, pilot instinctively pulls power to arrest the descent. This exacerbates the slowing down of the main rotor blades and they eventually stop rotating.

ALL of the above assumptions are based on photo evidence of intact RB's on impact. Remember that.

IF you assume this to be a fact then fuel/incapacitation/auto/manouevring/engine failure/tail rotor failure............has to be ruled out.

Earlier on there was another assumption: VRS. The cab would have to enter fully developed VRS within 700' / 30 seconds. Not practical.
IVRS would be an easy opt out - all mil pilots are trained to identify IVRS and simply trim fwd in cyclic and fly away.

Two other options haven't been mentioned but I am sure are on the AAIB's list of options:
They both commence with the letter S and one of them is sabotage.:(

But ......rotors slow.......pilot instinctively lowers lever.

TC: Wise thoughts and good observations as I see it.

The video footage from when lifting the EC out of the roof seems to show starboard engine loose from hinges and much below mounting position ? Or is it something else? If its the engine it points at very high G-force on impact.

Looking at the cabin, it looks compressed and as the front took more forces than the rear parts.

Spot on TC.

I saw what may have been the footage you refer to on BBC Alba's An Lá and I have just watched it again. It shows a heavily damaged lower cabin looking as though it were crushed by the momentum of the power train and top deck assemblies in the way that you describe.

This is consistent with the description given previously by a fire service officer who reported the work necessary to hold the aircraft together during retrieval.