Evil, the available/released facts would seem to support your statement. However there may be facts as yet undiscovered. Rumsfords Unknown knowns or whatever!
You should realise that the closer people on this thread were to the PIC and/or the type of operation, the harder it is for them to accept the kind of statement you made in post #83.
Logic would dictate the story is most likely more complicated than that.
I would be mindful of peoples sense of decency and compassion. In particular the Hill of Hindsight is no place to grandstand unless you are of course perfect and without potential fault. For example, despite many years of experience in several different operating environments, I never really digested the difference between thermistor/capacitance detectors and the vital role they play in the indicating, caution and warning systems until this accident brought them to light. I suspect the PIC was similarly indisposed but that is just an opinion.

I would also add, that being on the other side of the fence for a while, the OEM took some flack in this accident. However, when you fully understand the design concept of such systems and then listen to the engineers express their surprise at how poor the knowledge and understanding appeared to be, generally, amongst the Pilot community, it can be humbling. To a design engineer, us not understanding why he used thermistors as the backstop warning system, coupled with an apparent failure to follow the FM Procedure when the lights come on is just inexplicable to him.
As a community it is important WE do not seek to blame or achieve the simple satisfaction that comes with abrogated responsibility. In the end, we should always look inward. If it can happen to Dave....it can happen to me. What can I/Should I do about it?
The rest is just hot air and conjecture.

Look, we can all be under pressure to continue and get the max out of the aircraft endurance and are often pushed to use the absolute maximum available to get the job done. However, in this case the PIC used all of that and then all of his reserves and ignored the warnings until there was NONE left and the engines flamed out due to fuel starvation. At any time during flight the PIC should know their fuel state and that required to return to base or a safe point of landing with reserves intact, that didn't happen in this case.

not survivable
 

Personally, I don't need any special hidden story to picture what possibly had happened:

- your job is to fly a type notorious for various fuel level indicator flaws (stories from the fire fighter brigarde about pressure washing engines hot or cold, tiny but effective water droplets in the tank, etc)

- your boss tries to stretch a sortie as far as possible, almost bordering on having you cut into your fuel reserve

- its pitch dark outside

- you constantly have to toggle them dry-run sensitive fuel pumps, due to an inferiour fuel pump type (at least compared to EC135s ancestor BO105, which has a similar tank setup but dry-run capable pumps)

- these very important switches are overhead, hence out of sight

- you keep acknowledging the "faulty" low fuel warnings, while the main tank gauge indicates "~80kg remaining" (hence you are convinced they are as faulty as you've heard. Nobody told you about the sensor types and their extremely different sensitivity to ingressed water)

- while the display still indicates ~80kg of fuel the first engine dies on you

- with the home base lighting in sight, you frantically try to prepare for OEO flight, assured that you've got another 1,5 mins till silence, hence can fly home

- trying to get home on one engine with still "80 kgs remaining" indicated, the second engine goes silent "prematurely", some 30secs after the first

- now the cockpit goes truly black, rad-alt and landing-light gone, thanks to stupid electrical setup

- real panic sets in because nobody ever let you practize/demonstrate a "both engines at idle" autorotation, let alone a true EOL (not even in a sim?)

- the acoustic environment is waaay different than usual, RRPM indicator is as black as the rest of the cockpit, RRPM hard to tell by ear (wearing a helmet)

- between overrevving the MR and trying to arrest a "normal" RRPM, (hard to tell w/o instrument or visible blades) you are trying to pick a landing spot

- you end up below the min. end of the "RRPM power off" arc

- end of story


I don't see how this is survivable for anyone.
Who would have taken the time to mentally backtrack all previous actions to find the wrong pumps to be on?

So many systems were preceived by the pilot to have failed:
- recurring low fuel warnings while 80kg indicated in main tank, although one recalls humbly acting on the illuminating pump dry run indicator lights mutiple times in this very sortie, hence reasoning "it can't be the pumps"
- engine starving while 80kg indicated
- second engine starving way earlier than stated in the POH

There is only one on single contribution of the pilot to this accident:
having switched off both transfer pumps and switching on both prime pumps.

Anything else is airbus' fault:
bad choice of fuel pump type, necessitating unnecessary, error prone pilot work
bad choice of fuel sensor type, water-droplet sensitive fuel level sensors are a stupid choice
bad choice of emergency electrical power (it costs one(!) diode to fully automatically route battery power to the bus, thereby taking over supply when both generators fail)


That accident would never have happened in a BO105:
when both engines are running you make sure both transfers pumps are on, switch off the prime pumps and forget about pumps until you land and shutdown.

Pretty interesting that the finger is being pointed at the manufacturer rather than the pilot that flew the aircraft out of fuel...

My take is that the manufacturer made it really easy to fly that type out of fuel,
especially considering the frequently recurring fuel indicator issues of the EC135 fleet
("When the manufacturer tested the fuel sensors that were returned from the worldwide fleet, for repair, it found about 70% had no fault. ")
and mixing fuel level indication sensors with very diffent technology (water ingress sensitivity)
and the finnincky fuel pump toggle-'em-switches setup,
let alone putting misleading instructions in the POH regarding time difference between engine fuel starvation left/right
nicely rounded off by an overhead shed-bus switch, that has to be manually addressed to get rad-alt working, right when one has all hands full attempting an autorotation.

It's hard to picture a design less fail safe than the EC135 fuel system,
which is a shame as the mentioned BO105 already showed how a zero attention fuel system might look like.

Then again maybe you are right. There is that BO105 that was NVG-readied by fixing a filter glass over the warning panel using some duck-tape(!) :ugh:

1 Pilot fogot to switch on main pumps after engine start,
2 DIY installed filter glass moved downward during flight, causing the duck tape to block the "low fuel" warning light
(the holes in the cheese are aligning)
=> and at 20 mins past midnight, over the river Elbe in Germany he had one engine die (200ft AGL) and 4(!) seconds later (150ft AGL) the second engine starved of fuel.

He did an AR at night into the shallow part of the river. :ok:
They got their ankles wet, noone injured, helicopter only slightly damaged.

Recommendation by the authority:
Change BO105 POH to required all four pumps to be on from before startup.

german language report: https://www.bfu-web.de/DE/Publikatio...ublicationFile

When you are at the limit of endurance (which one assumes you are aware because of the watch/the physical position i.e. on the way home) at the point when the first engine flames out then surely you think fuel ahead of a wider problem?? And if you do think fuel dont all pumps go on by default and if you damage a pump through some dry running then so be it??

i just can not imagine that at this point in his trip fuel state isnt the assumed cause of all the problems and if 80kgs is being indicated at the point of engine flame out its hardly a time to over think things?

GC47G Sadly I cannot remember the detail now. Its over 20 years since I retired. Our practise re overnight refuelling was this. We had a large capacity mobile bowser at the unit. It was powered by an on board diesel generator. The fuel farm which closed at about 6.00pm would come over last thing before finishing and ensure that our own bowser was fully topped up. Then the aircraft would be refuelled as required during the remainder of the night from our own bowser. Refueling would always be at the direction and supervised by the PIC. At that time all of our observers were long time members of the unit, and well versed in the method of refuelling. They worked very much as a team, which is why I have always pressed for detail of the crews conversation with their control room. I cannot believe that my guys would have just sat there with the warning lights illuminated and said nothing to their C/R. But we've been through this conversation before, and I accept that that avenue was covered.
It seems that there must have been some form of CRM failure.

TF

If someone's actions are irrational then there are only two possibilities. The individual is irrational (possibly temporarily). Or he appears irrational because he is seeing something differently to you or seeing something that you can't see. We'll all have a different opinion on what happened here, but I made up my mind long ago that David Traill (and possibly the other occupants) was probably not mad but was relying on/basing his actions on information presented to him in some form that was erroneous. And that erroneous information may not have left footprints.

I am with SRP - The only way to understand "pilot error" is to try to understand why the actions taken looked rational to that pilot in those circumstances at that time.

on the subject

Coverage of Enquiry online by Scottish Review
 

The on line weekly magazine "Scottish Review" has had a report from the enquiry since it began.

Here is the latest; published this morning.

If you look at the sidebar you can find the 3 or 4 previous articles.

Scottish Review: Maurice Smith

that looks an interesting book, I'm going to read it. Thanks.

Big Frank's link has some worrying comments about how an experienced engineer who raises concerns about engineering workload at Glasgow, is ignored by his line manager and his action in reporting his concerns dismissed as 'unprofessional'..

Yes. Complex long FAI need somebody there listening for the small but important details. The Determination is the final output document, that addresses the specific points in the Act that I posted previously, and is public, but the Transcript is available only to 'Interested Parties' (those legally represented). Even in the Transcript you will miss the emotional impact of some of the points and importance of tiny decisions made along the way: the smaller holes in the cheese.

Even if it was considered that what he wrote and how he wrote it was "unprofessional", any line manager who read such a thing should be asking themselves "How tired, stressed and desperate does Bloggs have to be to write something like that?" Even if they do not consider that the point he raises is a valid concern the manner in which he is speaking is indicative of a significant Human Factors problem that should have been raising flags.

high spirits - when the inexplicable occurs and all rational circumstances and behaviour have been thoroughly investigated, it's normal to start looking at seemingly ridiculous reasons, however unpalatable they may be. By all accounts DT was an excellent pilot, but he was still human and humans (as we see with alarmingly increased frequency) have a habit of appearing to behave perfectly 'normally', while harbouring psychological issues that only surface when it's too late to prevent tragedy. If we ignored certain avenues just because "I knew him and he would never do that", we're denying that unknown mental health issues exist and can manifest themselves in unpredictable behaviour. Sorry if you're offended, but it's a possibility that cannot be ignored, just because you never witnessed an argument between him and his colleagues.

TOPTOBOTTOM, There is some merit in what you post. We had a very strange set of circumstances surrounding a well respected and seemingly stable colleague who decided one day that life was just too much for him! Inexplicable.!
However, in this case I believe there is sufficient evidence (or lack of) to see DT being led down the garden path by the indications in front of him. Having said that, someone most probably switched both transfer pumps OFF during the flight!! In the end, that will most probably prove to be the root cause of this tragedy. It is no surprise that the current recommendation on seeing or hearing any fuel warning is to check the TFR pumps switches and CBs. It is simple fuel system. However, like most simple systems a "simple" simplex mistake can be catastrophic.
For these reasons I don't buy into the psychobabble theories.

Amber PUMP cautions = Pumps OFF = Supply Tanks Draining + Faulty Contents indications + Poor Confidence in the warning & cautions systems = No appropriate response from Pilot = 2 x Flameout = pressurised auto = uncontrolled descent.

It could be that the supply tanks indicated FULL throughout. It could be that despite the "Memory" in the CAD that neither the Visual or Aural warnings manifested themselves properly in the cockpit. However, for all that to happen the Transfer Pumps HAD to be switched OFF!. In my view this is the only tangible and relevant piece of information that current EC135 pilots needs to assimilate. If you leave the TRFR pumps OFF, the supply tanks will eventually run dry.

The sideshows of maintenance histories, anecdotal events of a similar nature, training, system design are all for the Sherriff to digest and decide upon.

Toptobottom

Sometimes the unthinkable does need to be thought. But after an exhaustive investigation by the AAIB (during which they will have considered the unthinkable, the thinkable and everything in between) they have come up with a number of facts and conclusions, none of which include the scenario you suggest.

To make this suggestion, in disregard of the investigation findings and with no evidence whatsoever to support your accusation (and much to disprove it) is scurrilous, ignorant and dishonourable.

OH

Airbus: lack of priority for safety issues
 

That certainly seems to be a rational conclusion given that the latest evidence, link below, says that it took them over a decade to come up with a solution for what seems to this layman to be a major safety issue of which they had been clearly informed .

Apparently that is the view too of a witness from a British helicopter operating company who stated that the attitude of Airbus appeared to be:

, " ...[Y]ou use your design department rather than us using ours to come up with a solution...."

Scottish Review: Maurice Smith

From the Scottish Review:
Well that's two people who have no idea what they are talking about.

Latest report on Scottish Review website
 

Scottish Review: Maurice Smith


(The FAI has, it reports, been put on ice till at least the beginning of July; though I presume that the timing of the next report mentioned in the text as early August is due to non-publication of the "magazine" in the month of July.)

More to the point, the brief report does seem to repeat/ reinforce previous testimony about a known degree of unreliability of warning lights.

And about a failure to address the problem?

There was no drill for the FAILURE of BOTH Transfer Pumps before the Main Tank was empty, if that is what you mean.

Having noticed this, not log after we got our 135, I can recall taking off with both pumps switched OFF(on purpose) to see what would happen. In the cruise, the contents of the Main Tank reduced as the fuel went through the "overflow"(correct term forgotten) into the Supply Tanks for a while, but at around 250kgs indicated in the Main Tank, the Supply Tank contents started to reduce, with the Main Tank contents staying the same.

So, if BOTH Transfer Pumps failed below 250kgs in the Main Tank, you would only have the contents of the Supply Tanks for use.

No, the only time that it should occur is when the main tank has run dry.

Thats why you need a rating for flying helicopters, where in the theorie part - which requires a test to pass - things like the fuel system are covered.
(Tanks, capacity, pumps, usage i.e.)
When someone gets captions about the fuelstate, pilots normaly get realy sensitive, checking the fuel state and how much fuel is in which tank, knowing, that there might be unusable fuel, depending on which pump isn´t working.
Knowing, that the engines take their fuel from the feeder tanks does mean, that they are the tanks I focus on.
If fuel isn´t transfering from the main tank, I do something about it or make decisions to asure a safe landing.
We wont get an answer, why this time the obvious wasn´t done or which assumptions led to continuing the flight, despite the warnings.
But I won´t blame it on the general fueltank/pump setup, which is used in hundreds or even thousands of helicopters worldwide.
(Bo105, BK117 all variants, EC135, EC155) and except from an autorotation, where the crew covered the warning lights with duct tape, I don´t recal incidents which are related to the general setup.