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FAI into Clutha crash opens

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FAI into Clutha crash opens

Old 5th Nov 2019, 05:37
  #161 (permalink)  

 
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There is a world of difference between a real one (been there, done that) and practising, which is generally not done in twins*, and practice, especially when you do not expect it, and especially when you expect one engine to flame out after another over a rather longer timescale than is shown here. With modern helicopters having lighter blades, it would not be hard to lose NR.

*At least the 355 has a single engined equivalent to practice on.

I've not flown the type in question, but it seems to me that it has a similar quirk to the 206L where you can have much less fuel available that is indicated, and that doesn't even have a computer.
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Old 5th Nov 2019, 06:31
  #162 (permalink)  
 
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Hi all,
I can understand Daves Finace - she's emotional involved.
Have more than 1.300 h under NVG - similar tasks - landed more than once with only fuel in the support tanks....
And there is more to the situation - there are more crew members involved - talking to each other, interrupting actions/thoughts, possible putting further pressure on or influencing the decision making....
(What is the employer saying, if you land in a field and order a fuel truck?)
So I think, I have also an general understanding for Daves situation.
Who thinks, it could´t happen to him should take some simulator sessions with an instructor putting pressure on....
Still - as nearly always - it is up to the pilot in command to make the decisions - and get blamed, if it was the wrong one.
What I learned from experience but also from this crash is - better safe than sorry - play it safe - if in doubt, expect the worst scenario.
We have a short reminder, which helps in the process, called
"FORDEC"
F-acts - what happened, what information do I have (cautions, indications i.e.)
O-ptions - which do I have - i.e. engine restart? land? where? continue?
R-isks - to the options I have evaluated
D-ecison
E-xecute - the decision
C-heck - wether my decision is working as planed - otherwise start from the top again.

By now I´m much more willing to say no / cancelling or delaying a mission - interrupting for refuel - without feeling bad - cause I know, what can happen, if someone lets the pressure influence the flight.
If this accident and the discussions leads to more safe decisions - it wasn´t worthless.

To the question about the autorotation - 30isch seconds between failure of the first and the second engine isn´t really much time, especially, if you haven´t expected the failure of the first engine at this time.
So while getting the picture of what happened and dealing with that emergency, the second done failed on Dave.
I´m not really surprised, that the Nr decayed during the autorotation.

Still - also something to learn for Eurocopter/Airbus pilots - if you expect an engine failure due to fuel starvation / and possible the failure of the second one, why not switch the Shed bus to on?
No harm done, if you don´t need it but time and hands of the controls saved in case of - a point for the O-ptions, when the Fuel lights come on.
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Old 5th Nov 2019, 09:27
  #163 (permalink)  
 
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I find it distressing and incomprehensible that given months, not moments, to consider the facts, the Sheriff Principal has come to this conclusion. He chose not to concentrate on the fact that the EC135 model of helicopter has a history of faults with the caution advisory display, specifically a history of erroneous or spurious fuel indications, amongst other technical problems such as contamination of the fuel tanks, issues still never fully resolved by the manufacturer.

I have never flown the type involved, but bearing in mind the above - and assuming that any pilot of the type is aware of these facts - would it not be prudent to fly with the maxim "if in doubt chicken out"?
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Old 5th Nov 2019, 23:00
  #164 (permalink)  
 
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Originally Posted by jellycopter View Post
The biggest question for me, which does not seem to have been fully addressed, is the unsuccessful autorotation. Flaming-out both engines due to fuel starvation is one thing, but an accomplished pilot losing NR so catastrophically has me baffled.
I think it was addressed. Firstly the (false) expectation that there would be a much longer period between engine flameouts, and secondly that when 500’ agl over a city at night without a radalt or landing light, a successful autorotative landing is highly unlikely in reality. Which is true.

If you would like to demonstrate that you have made a successful engine off landing in a built up area from 500’ at night etc, then I might be persuaded otherwise but failing that, I’m with the sheriff. Those who think they could do it have never tried it..
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Old 6th Nov 2019, 02:06
  #165 (permalink)  
 
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There is a world of difference between a real one (been there, done that) and practising, which is generally not done in twins
Was part of every ride in our outfit, throttles chopped at 1,000 for a 180° or straight in and power restored in the flare. One instructor (76) left the power at idle so you got to do one to the ground as a one off confidence builder, we all had plenty of 76 time by that stage. Not prebriefed, if it looked good he left you to it, very surprising when you pull and there's nothing there.
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Old 6th Nov 2019, 05:59
  #166 (permalink)  
 
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Originally Posted by HeliComparator View Post
I think it was addressed. Firstly the (false) expectation that there would be a much longer period between engine flameouts, and secondly that when 500’ agl over a city at night without a radalt or landing light, a successful autorotative landing is highly unlikely in reality. Which is true.

If you would like to demonstrate that you have made a successful engine off landing in a built up area from 500’ at night etc, then I might be persuaded otherwise but failing that, I’m with the sheriff. Those who think they could do it have never tried it..
HeliComparator. I'm not saying that I would perform any better or worse in the circumstances as presented. I've certainly never done an EOL at night from low level over a city in an EC135 - but then I'm guessing no one else other than David Traill have either. Not having done it personally, does not preclude intellectual debate as to what might have happened.

My observations from the AAIB report are that the aircraft crashed with zero ground speed and zero rotor RPM. That's quite an achievement from 500(approx) feet agl and about 100kts groundspeed. If the pilot did nothing at all, the aircraft trajectory would still have some forward element would it not?

The report stated that the Low NR warning activated twice, was extinguished twice and then activated a third time and remained on. My hypothesis is that the first warning activated shortly after the second engine failed. The pilots instinctive reaction would be to lower the lever. If there was a restriction and the lever couldn't be lowered fully, only partially, a cyclic flare could recover the NR. This could potentially be achieved a second time but once forward airspeed and hence flare effect is depleted there's no further way to recover NR. This scenario could explain the rotor stall and the lack of ground speed.

Could something as simple as a clipboard or tasking folder have been in exactly the wrong place at the wrong time? I find this more plausible than a pilot of his experience, with heightened awareness after the first engine failure, simply mishandling the autorotation (albeit in exceptionally demanding circumstances).

JJ
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Old 6th Nov 2019, 08:37
  #167 (permalink)  
 
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With regard to Dr Thomas’ statement:

“Distressing” – understandable given her personal loss.

“Incomprehensible” – then she has not been listening.

“given months, not moments” – actually, the Captain of the aircraft had at least 8 minutes of the Low Fuel Sensors telling him to land the aircraft which he acknowledged but failed to act upon.
“history of faults with the Caution Advisory Display” – Not so - the CAD only displays what it is being told to display by the various sensors connected to it. Like any other computer, [email protected] in – [email protected] out.
“specifically, a history of erroneous or spurious fuel indications, amongst other technical problems such as contamination of the fuel tanks” - correct and still being reported.

Having experienced the phenomena of being told one thing by the display/qty sensors and another by the Low Fuel Sensors in similar circumstances to JT2as far back as 2007 and 2012, it also caused confusion initially but, nevertheless the aircraft was on the ground in very short order. As a result, like JT2, I also spent a day in the witness box at the FAI.

It wasn’t until I was being interviewed by Police Scotland during the evidence gathering process in 2017 that I actually did the maths on this one and it really hammered home the point. For those who haven’t done it yet:

Take off at 2044, crash at 2222 = 98 Minutes.

Fuel indicated at Startup = 400Kgs, Fuel found in wreckage 76Kgs = Fuel used 324Kgs.

EC135 Fuel planning figure 200Kgs per hour/3.33 per minute.

324Kgs used divided by 3.33 = 97.3 minutes.
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Old 6th Nov 2019, 09:28
  #168 (permalink)  
 
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Could I request that people take time to read the full report before any further comments on the Sheriff’s conclusion. The press are misrepresenting the gist of his words. What he is saying is not condemnation of Dave. It could have been worded better, but he disagrees with the AAIB to some extent. He believes that Dave’s actions were that of someone being Led/confused by the indication in front of him, leading to him doubting the red warnings and ignoring them. In other words, mitigating circumstances. However Dave’s decision to not believe the warnings was ultimately his decision. He didn’t recklessly accept a new task like the papers are implying, but he did choose to not believe the red warnings. That identification of the mitigation was the best outcome that I could have hoped for. He made an error of judgement, NOT a reckless decision.
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Old 6th Nov 2019, 10:17
  #169 (permalink)  
 
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Originally Posted by jayteeto View Post
Could I request that people take time to read the full report before any further comments on the Sheriff’s conclusion. The press are misrepresenting the gist of his words. What he is saying is not condemnation of Dave. It could have been worded better, but he disagrees with the AAIB to some extent. He believes that Dave’s actions were that of someone being Led/confused by the indication in front of him, leading to him doubting the red warnings and ignoring them. In other words, mitigating circumstances. However Dave’s decision to not believe the warnings was ultimately his decision. He didn’t recklessly accept a new task like the papers are implying, but he did choose to not believe the red warnings. That identification of the mitigation was the best outcome that I could have hoped for. He made an error of judgement, NOT a reckless decision.
Well, the Sheriff isnˋt an aviator.
So his view is legit, but we know, that we as aviators can’t follow/understand Dave’s Decision making, especially knowing, that normally every pilot should have a general idea about his endurance.
As the calculations show, a started stopwatch at t/o would have given him the same information as the warnings did, which he ignored.
And getting a fuel warning, you surely check the indications, but also their plausibility against time flown.
There sure was a human factor involved, which isn’t covered, cause we don’t know, what conversation happened in the bird
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Old 6th Nov 2019, 10:27
  #170 (permalink)  
 
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Did the Police ever provide a transcript of the police comms?
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Old 6th Nov 2019, 18:43
  #171 (permalink)  
 
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Originally Posted by Flying Bull View Post
As the calculations show, a started stopwatch at t/o would have given him the same information as the warnings did, which he ignored.
FB - I'm not sure that's the case. The calculation would have shown him that he had about 75kg left - which he did - the problem is not how much fuel he had (enough for a good twenty minutes) but where it was, ie not in the supply tanks. Or have I misunderstood something?
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Old 6th Nov 2019, 19:04
  #172 (permalink)  
 
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Originally Posted by MaxR View Post
FB - I'm not sure that's the case. The calculation would have shown him that he had about 75kg left - which he did - the problem is not how much fuel he had (enough for a good twenty minutes) but where it was, ie not in the supply tanks. Or have I misunderstood something?
Well, checking where the fuel is, when you get a warning, is part of the checklist.
Evenso I landed under minimum fuel required (a couple of times), I always had a very close eye, on where my fuel was (balancing it in another ship) to avoid an early flame out.
20 min was less than required for landing by the operator.
Going below minimum fuel can happen in aviation - but I think, a very very good reason is required to accept this extra risk - i.e. a life saving mission.
And when doing so, evaluating the associated risks - and having a plan B, in case of miscalculating the fuel available.
We don´t have the police control information here - but the flight path, hovering here, hovering there, which doesn´t really implement, that they found somebody where the ground forces needed guidons to rescue them.
I know, at the moment I´m more the devils advocate - but thats my point of view.
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Old 6th Nov 2019, 21:02
  #173 (permalink)  
 
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My ac had 46kg in the tanks. It read 116kg on the gauges.
i was expecting around 120 kg so it all looked ok.

what I DIDNT know was that at the start of the day, my 400kg on the gauges was actually around 320kg in the tanks.

A stopwatch was as much use as tits on a bull
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Old 6th Nov 2019, 21:21
  #174 (permalink)  
 
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Originally Posted by jayteeto View Post
My ac had 46kg in the tanks. It read 116kg on the gauges.
i was expecting around 120 kg so it all looked ok.

what I DIDNT know was that at the start of the day, my 400kg on the gauges was actually around 320kg in the tanks.

A stopwatch was as much use as tits on a bull
I’m not familiar with civilian operation but didn’t the refuel log (tech log?) and the engineers who did the refuel not detect the discrepancy? Or was it a known fault but an acceptable defect?
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Old 6th Nov 2019, 21:36
  #175 (permalink)  
 
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If tanks don’t get topped, run down to a warning light, or even more unlikely drained, one is surely not going to know whether the gauge readings are accurate. I guess in a police role with with heavy loads such a scenario could continue for several weeks and maybe months. Not of course that this should change response to a red low fuel warning.

Last edited by rotorspeed; 6th Nov 2019 at 21:48.
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Old 6th Nov 2019, 22:28
  #176 (permalink)  
 
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Rotorspeed, correct. We suspected that it built up over a period and I was the first to run it that low for a while.
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Old 7th Nov 2019, 10:23
  #177 (permalink)  
 
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Jay, is it not possible to use a `dipstick` ,or torch to check on the ground ( I know ,slope ,etc)...?
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Old 7th Nov 2019, 11:14
  #178 (permalink)  
 
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sycamore, neither would work on a 135 - the filler tube goes through a 90-degree bend; fuel only sits in the upper portion of the filler when the main tank is within 8-10 kg of full, which would never be the case on a UK police operation.
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Old 7th Nov 2019, 11:41
  #179 (permalink)  
 
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Originally Posted by Flying Bull View Post
.
As the calculations show, a started stopwatch at t/o would have given him the same information as the warnings did, which he ignored.
Fly Bull, me thinks there is a lot of "Bull***t" in your statement above.
Starting a stopwatch to calculate your endurance during Police Operations is about as much use as an ashtray on a motorbike!
Hovering, circling, balls-out to the next job. The fuel consumption is up and down like the proverbial whores draws!
Dave Trail deserves better. Like I said earlier. The hill of Hindsight is just that.
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Old 7th Nov 2019, 13:56
  #180 (permalink)  
 
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T &B, thanks.....
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