In the bar
 

Good point , you may well be correct, I was in a negative mode , lets hope that's what he meant

No more from me , too many bad memories !!

I didnt say that the blade was lost in flight.
Its just not there anymore and for me it looks like it broke off at impact.

Such an event would be expected to manifest a number of temp and pressure warnings in the cockpit, and a precautionary landing long before it all goes into bits.

Bird strike ?

Do not most birds roost at night as they cant fly in the dark ( small eyes etc etc ), yes I know owls and some hunting birds do but generally most don't fly at night

Post 534 chills me - I can't get it out of my mind. I have seen enough from pics/witnesses and debris to satisfy myself (A) the cab fell completely out of control and (B) it fell absolutely vertically with no sideways trajectory. The imprint on the ground matches exactly that of the circumference of the cabin area. There were no horizontal signs of motion.

I know it's difficult for newcomers to simply log on and write something but please at least do the rest of us the courtesy of catching up with what has already been said.

David had NO time to enter auto - the blades had stopped....that is a fact evidenced by the stationary condition of the MRH on impact.

Current police pilots - remind me (it's been a while): can you transmit if both engines are offline/genny's offline? Or does the pilots VHF come off the Bat busbar? I suspect the latter due to ANO requirements. Just checking.

Second Q: Were the bobbies using airwave/encrypted, if so, I wonder if they got a mayday out to the control room/bobbies on the ground?
If they weren't on Airwave - are there any radio hams out there who were monitoring their transmissions?
If both pilot 'victor' and police radios ran off the primary or DC bus. And if the gennys were offline because the engines/MGB wasn't turning - that is why nothing was transmitted.

I'm very intrigued by the Av8r post. By low side I presume you mean one of the ECU's suffered a runaway down yes? And the pilot didnt restore it or fly manually on that ecu during his recovery - to sustain Nr?

AgBis: You still think he was in fwd flt?

Non PC Plod - good to see you pop up on radar buddy! You aren't serious about TR failure from a hover are you? They are survivable - as you know - provided the pilot instinctively winds the collective fully off in a 135. From then on its a hairy auto but the Nr would be retained even if you did run out of air. And this incident categorically shows no MR movement at impact??

Kenneth - you have joined us late. This topic you discuss has been discussed here on this thread and on nearly every other 'sad' thread since Pprune started. It is part of the fabric for this site it is our way of venting frustration, sharing ideas, satisfying our curiosity. Pilots are a curious bunch!
The best analogy I heard was that if we were all in a crewroom (because this is after all an aviation website) - we would most certainly be discussing it from dawn to dusk and beyond.
It comes with the territory Kenneth - sorry.....and shut the crewroom door on your way out please?:ok:

"Quote:
'Something like a MGB with no oil?'

Such an event would be expected to manifest a number of temp and pressure warnings in the cockpit, and a precautionary landing long before it all goes into bits."

That answer might be slightly misleading to a casual reader. Many transmission temperature indications are actually transmission oil temperature- no oil, no flow past the temp bulb, no meaningful XMSN temp reading. Probably no chip lights, either.
Absent a transmission oil pressure GAUGE, a transmission pressure caution segment/light and a crosscheck of XMSN temp/chips for secondary indications could lead one to serious error.

TC,
ATC 2 is direct off the battery so would be available. ATC 1 requires avionics on and either the shed bus switch or a generator online.
Airwave head is same as ATC 1.

Army AV8TR,

I agree with your point about Nr; seems like there were two problems, one the loss of power (for whatever reason), then the inability of the aircraft to maintain at least min autorotation rpm (see my post about unseating or damage to swashplate/pitch control mechanism).

Just looking at the apparent failure to autorotate all the way to the ground, apart from mechanical damage to the pitch mechanism etc, there have been aircraft lost due to mis-rigging where they can't get enough pitch off to auto. Would take two pieces of the cheese to line up, but then that's happened before too.

Hi devil - still an extremely unlikely condition......even if you leave the temp and chip cautions out; you get two MGB press cautions AND a MGB press warning with audio.....not very easy to ignore

Also, the initial impact was described as sounding like a gas explosion

This was a very heavy impact, whether a complete free fall I will leave to the experts to decide. The pub effectively had three ceiling, this seems to explain the delay in the roof collapsing after the initial impact.

Agreed - as I said originally, 'the thought crossed my mind'. I stand by the point that, in any situation where a single pilot faces a nightmare scenario at night, he will not have an internal Google Map allowing him to remember every detail of the lie of the land thereby knowing which dark area is waste ground/car park and which is a single-storey flat-roofed building.

We're running away with ourselves here guys, and adding speculation on top of assumption on top of guesswork. The one thing I have learned (painfully!) about accident investigation, is that nothing should ever be taken in isolation.

We have pretty much reached the end of the road now as far as guessing is concerned. I'm not being 'huffy', but what is the point of any more theories and opinions?

There is hardly anything that can be said with certainty here, other than it was a tragedy.

Time to pause. Thank The Lord it wasn't us, and wait for AUTHORATITIVE information?

That way 99.9% of us won't end up looking like total dickheads!

TC,

TC Yes I'm serious - a TR drive failure in the hover is potentially survivable.... IF you act pretty darn quickly. If its the middle of the night, you have been flying for 2 hours, and you have not been pre-warned by any warning lights etc, then the chances are you are going to take a couple of seconds whilst your brain goes "What T.. F..!!".
If you were hovering at the time, you could be spinning like a top after 2 seconds, and even with the engines off you would be lucky to get control back before you hit the ground unless you started very high.
On the simulator I work in (although it is a different type) following a TRDS failure in flight, if the pilot lets the speed reduce sufficiently that the nose departs to the right, then I think I am right in saying that once in 6 years have I seen anyone recover the situation sufficiently not to crash.
The airflow is disrupted so much as the airframe spins, that it is impossible to get sufficient control to get the nose down and get airspeed on, and it pitches and rolls as it spins. Never fun.

kennethr
 

Just to clarify my comment

"It has been the most terrible tragedy, and I feel tremendous sympathy for all the families, friends and colleagues who have been affected both directly and indirectly. Perhaps we can take some comfort in that they passed on to the next life doing something that they loved, both in the skies and in the bar."

My sentiment was that the crew of the aircraft were doing a job they loved, police aviation. It is one of the most challenging and rewarding roles within the police service. Selection procedures are tough, and only a small percentage of applicants make it through training.

The second part, was referring to the poor souls who were within the bar. I imagine that in a crowded pub, at the weekend, drink was flowing, music was playing, and they were surrounded by friends and family.

If i were given the choice of when i meet my maker, I would choose either of the above scenarios over being sat behind a desk or sat alone watching the coronation street omnibus eating a lasagne for one.

Police helicopter crashes onto Glasgow pub
 

Lots of birds can and do fly at night particularly clear nights. Small birds tend to cluster at night and roost together. There is evidence that they remain active throughout the hours of darkness and can be spooked by noise or predators. Big birds around the Clyde include Herons, swans and geese. Having said that I remain skeptical that a single bird strike would be catastrophic.

Devil, as I have never flown an EC-135:
does it have an oil pressure guage on the instrument cluster?
Good point on needing oil for the oil temp to register. ;)

Non-PCPlod: I lost a shipmate some years ago in daylight to loss of T/R thrust.** The point your raise is worth considering, though I suspect that if the connection between TRDS and the Main Transmission were broken, such that no rotation was provided to the fenestron due to the drive link being broken all at once, the AAIB would have already put out the alert message. I think that such a breach of drive train integrity would be apparent to the investigative team by now. (If I am wrong, apologies to all on the team). This leaves open the question of "why rotors not damaged, hence not turning" per the evidence available to date.

TC's series of analytical posts account for the bulk of the evidence available to date, and paint a chilling portrait of the last few seconds in that aircraft. :{ RIP, gents.


** The crash where my shipmate died happened at A/S of about 100 kts, at between 300 and 500 ft AGL/MSL (same, as he was flying over a waterway out of a port on the coast) and was a surprise event.

The surviving pilot related how quickly they lost directional control ... the initial yaw due to T/R loss was not obvious at first, initially countered by pedal input due to yaw, but "yaw, full pedal, hey, it's -- " as the helicopter got broadside to the airstream, the A/S fell of rather quickly and what was wrong became apparent to them all of a sudden.
They lowered collective, down they went, flare, chopped throttles (might have flared a bit high, might have pulled the engines early, hard to say, no FDR) hit the water hard and more or less flat. The seats stroked full down.
He got out. (Back was a mess for a few years)
The fella in the back got out.
The guy not flying was knocked out by his head hitting the cyclic. (That was figured out later). He drowned.

Agaricus bisporus - how do you explain stopped engines and stopped rotors with the above scenario? If the pilot was incapacitated how could he shut down the engines?

I considered a large bird strike on the fenestron initially but ruled it out due to:
1. The time of night.
2. No evidence visible on damaged fenestron, blood, feathers, bent blades etc
3. It does not fit in with a vertical descent with no engines and a stopped rotor.

That's true, but it's not much use for looking out to the front, hence the need for the swivel one on the Shed Bus.

Let's think about EOLS:

Dave came through the RAF system, which trains you (in a single engine aircraft) various different EOL techniques for dealing with an engine failure, completing the exercise with the 'full blown' Engine Off Landing. Before others leap in I also realise that some ac - particularly the UH-1 and derivatives - have other techniques as well.

Firstly there was the 'standard' technique - the engine fails, flare back to approx 60 -70 kts (depending on ac) and lowering the collective, then manoeuvre the ac to achieve an into wind landing in a suitable field with a flare - check - level and run on. The harder the flare the less the run on speed but more chance of striking the tail. This is the EOL of choice when VMC in daylight and the ground (and suitable site) visible. The Rate of descent of most rotary will be about 1500-2000ft/min - but again AUM, DA etc will give differing figures. Variations of this include both range auto - drooping the RRPM but increasing IAS giving greater range but slightly higher RoD - and Zero Speed - again exactly what it says to enable a vertical (or even backwards) auto in strong wind but with a very high RoD of 3000ft/min or greater. Both of these techniques demand a return to the 'standard' technique by approx 500-800 ft.

Then there was the 'Min Speed' auto. This was to be flown at night/IMC or when the surface was obscured. Immediately flare back to approx 35-40kts (whilst lowering the lever of course) and turn back into wind. At night flick the landing light on. The RoD is now closer to 2-2500ft/min. When the rad alt reads about 30ft or so you rapidly raise the lever and hopefully cushion the landing. There is no attitude change (although a very slight nose up is possible) and the run on speed much more wind dependant. The idea behind this was that if you were to hit something close to the bottom of your EOL, 40 kts might be more forgiving than 70 kts! These were mandatory practice every month as well; to an observer on the ground they look almost like a vertical descent with a very high RoD. Come to Tern Hill to watch on a windy day! PFLs were also practiced at night (although without shutting the engine down) to a flare recovery at an airfield T (an arrangement of lights on the ground).

However, whilst these techniques were practiced on twins they were never flown to the EOL but only to the flare or overshoot. After all, two engines will never fail at the same time (so they said, until I found out they could!), or simulators are/ were available as well.


Now the conjecture bit.

Dave was presented with something catastrophic (gearbox, transmission or whatever) over a heavily built up area and enters autorotation. He might well have gone straight for the min speed technique (old training) and concentrated on making for an apparent dark area away from traffic etc. To observers on the ground it looks almost vertical, and if turning/manoeuvring may appear to be 'tumbling' as well. He might have had time to pull the Fuel shut off levers (hence the 'popping' sounds) and is also watching the rad alt to confirm his check height. The rad alt is reading from river/ground level until just approaching the LS, when it suddenly reads much lower (roof height) and he has to apply a lot more collective than anticipated to try to stop the descent so perhaps they hit the roof harder than planned. However, the rotors will then stop pretty quickly. After that events deteriorate rapidly.


I stress conjecture. I personally cannot see any way a helicopter can have the rotors stop in flight or enter a tumbling descent without some parts of it falling off / being ejected / completely breaking up - but again there may be a way this could happen that someone could explain. The only other anomalies to me are the lack of a radio call and lack of landing light.

My gut feeling is the aircraft was under some control before touchdown, and Dave would have used all his skill to achieve a safe arrival: unfortunately they didn't walk away from this one.

My feelings too. No visible damage to the MRBs does not necessarily mean they weren't turning, just that they weren't turning under power, or they never struck anything.

We haven't yet seen all 4 MRBs, it is possible that he auto'd onto the roof as per shackman's theory and there was so little kinetic energy left in the head that as soon as one blade hit something, they head effectively stopped.

We may never find out what truly happened in the last few seconds of this flight, but hopefully we may discover what caused them to be in that situation in the first place, whether it be catastrophic MRGB pressure loss, TR loss or other.