Originally Posted by jellycopter
(Post 10611005)
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.
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.. |
There is a world of difference between a real one (been there, done that) and practising, which is generally not done in twins |
Originally Posted by HeliComparator
(Post 10611773)
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.. 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 |
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, cr@p in – cr@p 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. |
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. |
Originally Posted by jayteeto
(Post 10612058)
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. 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 |
Did the Police ever provide a transcript of the police comms?
|
Originally Posted by Flying Bull
(Post 10612093)
As the calculations show, a started stopwatch at t/o would have given him the same information as the warnings did, which he ignored.
|
Originally Posted by MaxR
(Post 10612472)
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?
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. |
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 |
Originally Posted by jayteeto
(Post 10612606)
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 |
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. |
Rotorspeed, correct. We suspected that it built up over a period and I was the first to run it that low for a while.
|
Jay, is it not possible to use a `dipstick` ,or torch to check on the ground ( I know ,slope ,etc)...?
|
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.
|
Originally Posted by Flying Bull
(Post 10612093)
.
As the calculations show, a started stopwatch at t/o would have given him the same information as the warnings did, which he ignored. 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. |
T &B, thanks.....
|
Originally Posted by DOUBLE BOGEY
(Post 10613101)
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. |
Originally Posted by helonorth
(Post 10613253)
Fuel burn will vary but not to a large degree.
|
Originally Posted by DOUBLE BOGEY
(Post 10613101)
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. I have really no clue whatsoever, with a navy background, some freelancing and flying police ops since the year 2000 ... with Bo105, BK117 (B2/C1 Variants), EC155, H145. Hovering, cruising, transporting, loitering... experiencing different fuel states between hover and cruise, switching pumps. its standard, that the next mission(s) are given over radio- while on one mission. may be its due training with the RN, that I do a fuel check before takeoff, check the burn rate around every 30 min and have a close eye on in which tank my fuel is. Canceling warnings without reacting accordingly is just what I can’t understand from an aviator point of view if that’s „Bull....“ for you, I don’t want to fly with you... |
Originally Posted by Flying Bull
(Post 10613293)
double bogey, I have really no clue whatsoever, with a navy background, some freelancing and flying police ops since the year 2000 ... with Bo105, BK117 (B2/C1 Variants), EC155, H145. Hovering, cruising, transporting, loitering... experiencing different fuel states between hover and cruise, switching pumps. its standard, that the next mission(s) are given over radio- while on one mission. may be its due training with the RN, that I do a fuel check before takeoff, check the burn rate around every 30 min and have a close eye on in which tank my fuel is. Canceling warnings without reacting accordingly is just what I can’t understand from an aviator point of view if that’s „Bull....“ for you, I don’t want to fly with you... |
Helicomparator you haven’t really read my posts, have you? I wrote, that we don’t have - and I guess won‘t get the information, what was happening inside the bird in regards of communication/ human factors. I really know, that if the holes start to line up, the risk of desaster increases exponentially. Thats why you have to back off and re evaluate the situation sensing any hole, may it pressure on the crew, may it be weather, may it be any failure of hardware. And at the end, decide for the safety of the crew. With repeating warnings there is no really any reason to continue police work without solving that problem (hole in the cheese) first. I won’t say, I couldn’t oversee something- which I wrote before, everybody can reach his limits (easily shown in a Sim, if someone doesn’t believe) But been there I learned a lesson to back off early. Dave didn’t had the luck. |
Flying Bull...…"Bird" = Helicopter...really!!!
Chopper is bad but Bird...……. Some sick just come into my mouth reading that. |
DB, you need to get out more :) it is part of the lexicon in some areas of the business, as much as you may hate it, one dictionary includes the definition,
a man-made object (such as an aircraft, rocket, or satellite) that resembles a bird especially by flying or being aloft Then there is giving someone the bird. You hate these type of birds as well? https://cimg7.ibsrv.net/gimg/pprune....679f34113a.jpg |
Megan, I bow to your greater knowledge in favour of more "Bird" postings!
|
Originally Posted by MaxR
(Post 10612472)
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?
i think Captain Trail’s probable belief that both transfer pumps were on when in fact both were off persuaded him to ignore subsequent warnings. i did read every word of the FAI report. I can’t help agreeing with its findings. But I think that the fuel system of the 135 is an abomination waiting to trap the unwary in a totally false illusion that each engine has its own fuel supply to meet regulation. ive never flown the type, but it seems to me that there is never a time when both transfer pumps would intentionally be off together. so why not a single three position switch. Centre - Both on. Forward - Forward on Rear off. Rear - Rear on Forward off. and if you ever need both off a separate guarded switch to turn both off. |
“I've never flown the type, but it seems to me that there is never a time when both transfer pumps would intentionally be off together” Yep, when main is empty and fuel is only being drawn from the supply tanks. In simple terms, when there is no fuel to be transferred from main to the supply tanks, the transfer pumps are turned off. |
Sloppy Link Thanks for that. So only when the fuel state is quite low. Can’t remember the total contents of the supply tanks but roughly how much time would you have left once in that condition? |
Originally Posted by Arkroyal
(Post 10614855)
Sloppy Link Can’t remember the total contents of the supply tanks ? |
Originally Posted by meleagertoo
(Post 10612099)
Did the Police ever provide a transcript of the police comms?
meleagertoo.......... That’s the proverb able million dollar question !!!!!!! , I have always pondered on it myself, ( I DONT THINK SO ) But will always stand corrected if it has been provided , But the Dark place north of the Border Might never see the 9999 clarity to your question . |
Originally Posted by Sloppy Link
(Post 10614807)
“I've never flown the type, but it seems to me that there is never a time when both transfer pumps would intentionally be off together” Yep, when main is empty and fuel is only being drawn from the supply tanks. In simple terms, when there is no fuel to be transferred from main to the supply tanks, the transfer pumps are turned off. |
Originally Posted by GC47G
(Post 10614942)
meleagertoo.......... That’s the proverb able million dollar question !!!!!!! , I have always pondered on it myself, ( I DONT THINK SO ) But will always stand corrected if it has been provided , But the Dark place north of the Border Might never see the 9999 clarity to your question . Although Sheriff's determinations are available from the scotcourt website, transcripts are normally only available to the "interested parties" represented at the FAI. |
DB - you are very quick to criticise FB for his terminology, rather childishly in fact, since English is not his first language you could just cut him some slack.
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Originally Posted by DOUBLE BOGEY
(Post 10614185)
Flying Bull...…"Bird" = Helicopter...really!!!
Chopper is bad but Bird...……. Some sick just come into my mouth reading that. |
Arnold Schwarzenegger says “get in da chopper! NOW!”. He is the only one who can get away with it. I’ve never ever heard a British pilot or engineer call a helicopter a bird. ive always referred to it as a helicopter or aeroplane/aircraft |
Or cab (back in the day).
I hope Flying Bull continues to make his points and gives DB a severe ignoring. |
Originally Posted by HeliComparator
(Post 10614965)
except that the transfer pumps don’t need to be turned off, unless they are the crappy ones. Why not get rid of the crappy ones and then things would be much simpler and safer? No-one has bothered to do a risk assessment of the downside of the crappy ones vs ensuring that the pumps are the Test Fuchs type. What price making the system more error tolerant?
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Originally Posted by Sloppy Link
(Post 10615576)
The pumps do need to be turned off if that is what the drill says. |
Originally Posted by handysnaks
(Post 10615437)
Or cab (back in the day).
I hope Flying Bull continues to make his points and gives DB a severe ignoring. bye the way - there is actually a helicopter, which is official named bird MH-6 Little Bird Light Utility Helicopter | Military-Today.com ;-) To fuel pumps - not really the ideal situation, that with only little fuel left, either the front or back pump runs dry (hovering / cruise). Better to have pumps with run dry capability - but still, pumps are cautions, low fuel is a warning, which needs to be addressed accordingly. Different to the normal aviation world, where you have time and need to do a proper preflight planning including fuel planning (normally on a sheet which needs to be taken onto the flight), police and SAR flights and some military - get missions while being airborne. So you have to do inflight flight planning - but this should and normally does include fuel planning (trip / reserve fuel) And the planning needs continues fine-tuning with changing mission parameters. That it is demanding - at night - with two further crew members possible pushing towards mission completion - no question at all. Everybody operating in a similar environment should therefore remember this crash and adjust his decision making towards safety. |
FB, Crab and Handy Snaks, Thou have the right o call them "Choppers", "Cabs", "Birds", "Flingwings" etc.
Crab its been a long time since you have got your gander up at ,me. Now I am just getting to old to react. However, its a "Helicopter" or and "Aircraft" and it will always et my teeth on edge when someone calls it an odd name and "Bird" is the one that gets to me the most. FB, if you cant speak English proper like! Don't worry, In truth I am slightly dismayed that this whole subject has been resurrected. I thought it had already been thrashed out completely. Any way goona get back in me motor and mosey on down to the boozer before the Trouble and Strife finds out. |
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