Police helicopter crashes onto Glasgow pub

[that chinese fella]

Does such training and testing include the warning that approx 15% of fuel in main is/could be unusable if pumps are off?

Yes, it does. Not as a %, but as kg of fuel.

As does the Pilot Emergency and Malfunction Procedures checklist for either Transfer Pump (F PUMP AFT or F PUMP FWD) caution lights.

Further, as I am sure has been explained before on this thread - but I can't be naffed re-reading it all, there will be a FUEL caution light as supply tank qty falls and finally, as the qty falls even more, 2 big red warning lights (with a GONG) for LOW FUEL 1 and/or LOW FUEL 2.

On top of that the graphical display of the tanks will show the main tank not draining and the 2 supply tanks ebbing away.

Turning the Prime pumps ON at any stage of any of the above palava will technically do absolutely nothing to help the situation, let alone that turning them on is not a checklist item. The only time it is called for Prime Pump on is, aside from Start, is if FUEL PRESS (sys 1 or 2) caution lights come on.

Hope that answers your question. As I said earlier, I am not sure you could get a better system for letting you know when things aren't right.

[henry_crun]

Chinese - You mentioned limitations of nvg. Do you have any links to diagrams, manual, specs etc, please?

Or indeed anyone else with details of the particular type of nvg used on this flight?

Many thanks.

[mickjoebill]

That chinese fella,

Thanks, but my question is not about what is displayed to the pilot but what knowledge they have of the fuel system.

I am asking if pilots are aware, as general knowledge, that a significant amount of fuel is unusable in the main, if the transfer pumps are not working.



Mickjoebill

[Art of flight]

Henry,

The modern 135 T2/P2 cockpit lighting environment is built in at the factory to be NVS/NVG compatible. Unlike the generation before that had all sorts of additional bolt on blue/green glass panels and tin shields to reduce the glare from standard orange lighting.

[Art of flight]

MJB,

Yes, they are. It's fundamental knowledge and tested during 6 monthly OPCs and on a rotational basis during shift briefing emergency drill training.
Of course each unit has had it's own way of doing things but NPAS is standardising these things.
The units I've worked at all have large photographs of the various parts of the cockpit displayed in the briefing area along with 3 copies of the flight reference cards, one for each crew member. Typically at shift brief a TFO is asked to pick at random a card that displays a caution or warning, the pilot and other TFO then act in accordance with the FRCs, then if required the pilot gives an explanation of the drill and the underlying system including any limitations. A re-currency board is then marked with the initials of each participant against the list of emergencies covered, in this way all emergencies are covered around every 4 months or so and any changes are fed into the system through revisions to the FRCs.

[Art of flight]

Many years ago a colleague made a rig to film through the tube of a pair of goggles, for it's time (23 years ago) it worked really well. We were getting into the realms of night formation flying and TOW missile firing and needed to be able to debrief various worthies as to how their money was being spent and their technology used. I'll have a root about and see if I can find it any footage.

[henry_crun]

Sorry Art, yes I suspected that, but it's the nearest I can get to a vid of night vision aids, will take it down as soon as someone can post something nearer to what is actually seen by the pilot. Come on guys! Get out there with some nvgs and a camera! (but not while driving!)

PS - Thanks Art, hope you can find it!

Here is a pic published by West Midlands Police of their Night Vision Goggles, it may help non-fliers like myself to see what Chinese said about his method of wearing them high so that he can see through yet see the display information below, sort of bifocals. I'd be interested in hearing how other pilots deal with this focus problem.

[Art of flight]

Try this link

Night Helicopter Firefighting/NVG Training - YouTube

Nothing to do with my previous post but shows the cockpit environment and the view outside through NVG on a cracking night!

[henry_crun]

Thanks, Art. There is a view of the instruments albeit from the back seat, it shows how difficult it would be to see displays, what with the low resolution and the monochrome green display.

PS 0:15 shows scenery in good focus and instruments out of focus.

[Art of flight]

DAPT,

The RFM and cards don't specify an 'intermittent' condition for those pump cautions. They just have a drill for when the caution displays on the CAD.
The pilot then follows the drill for the caution. The flight condition (attitude) then changes and the pilot then re-switches to get back to normal. Then the caution appears again as conditions change, so the pilot carries out the drill again as if it had never occurred before. Now some might say (and have), it's stupid to keep switching the pumps on and off in flight particularly if the cause for activation is aircraft attitude, but pilot deviation from the drill is not part of the deal.

[Art of flight]

Yes Henry, you can't have the goggs in focus for the instruments and the outside, so prior to flight you set them up for outside (they are used above 500' agl generally) and you would use normal un-aided vision for cockpit duties/scanning instruments etc. Hence the phrase 'looking under the goggles'. Of course it's a matter of seconds to stow the goggles and brighten the cockpit lighting to deal with cautions and drills if so required.

[falcon900]

Firstly, a thank you to Silsoe Sid, who has put a lot of effort and thought into his many posts, and has shown a great deal of patience in answering questions, many posed not for the first time.
After over 2000 posts, it seems to me that we are arriving at a degree of consensus around there being a small number of potential hypotheses for the fuel situation which arose on the aircraft. In no particular order, these are:
1) Gauges, cautions and warnings worked normally, and a severe case of press-on-itis came over the pilot causing him to try to use his final 10 minutes of flying time after the red lights to return to base. ( personally, I discount this, not least because he would have been totally prepared for a flameout and the ensuing autorotation, and would definitely have been on top of the transfer pump situation.)
2) The fuel contents probes were reading optimistically, and no yellow cautions were shown. The red lights did illuminate, but the pilot considered them to be anomalous, and in the absence of the yellow cautions and the presence of fuel as shown by his gauges, was convinced he had enough fuel to complete the mission. (This is my hypothesis of choice. The main tank showed correctly 76KG, whilst the supply tanks erroneously showed satisfactory readings. He knew the transfer pumps were off, and knew he would need to turn them back on at some point, but also knew they would require management given the relatively low level of fuel in the tank. When the first engine flamed out, he was still convinced his gauges were correct, and that the problem was something else. Turning the prime pumps on and trying to restart the flamed out engine could have seemed logical and a good use of time, and could explain why he would not seem to have been well prepared for the second flameout.)
3) Due to a failure of the CAD, the pilot was denied information regarding the fuel state. ( I discount this on the grounds that the first flameout would have been a very rude awakening, and in the absence of data to mislead him into believing he had adequate fuel, he would have sought to land immediately.
I hope my summary hasn't overlooked any hypothesis which is still at large.
As an aside, while we await more data, is there a view as to why the operation of the transfer pumps is not fully automatic? The processing power required is negligible, and it would seem to offer a useful reduction in pilot workload.

[Art of flight]

Falcon, just when you think you've nailed it someone is bound to come up with alien abduction (again).

"The main tank showed correctly 76KG, whilst the supply tanks erroneously showed satisfactory readings."

My thoughts on this are, where did he think this other 'erroneous' fuel quantity had come from? The actual flight time of 1:35 is pretty much bang on with 400 on take off, 76 on landing. If the main did show 76 and the supplies showed enough to discount fuel as being at all the reason for a flame out as you suggest? He really must have known that after that flight time he'd have about the 76kg left in the aircraft.

[Art of flight]

I was once told that changing the design of an aircraft once it was in service was akin to dockyard engineering and the cheaper option would be for the crew (me) to adapt, and if the crew (me) couldn't adapt, they'd get crew who didn't think it was a problem.

[falcon900]

I hear you Art, but we have yet to hear of fuel probes under reporting the actual contents of a tank, so the main tank must have been showing 76kg surely? My hypothesis 2 does recognise that the supply tanks would not have been showing full, so the overall contents would not have been entirely implausible. Bear in mind, he was supposed to have a MLA of 90kgs, and had been prepared to take on non urgent extra tasking, all of which points to his being under the impression he had much more than 76kgs left.

[Art of flight]

No, but they would have to show an amount sufficient not to be linked to the Red warning and flameout for it to be true?

[falcon900]

Correct, and I think they erroneously did, causing him to attempt to relight the first engine to flame out, and amongst other things switch the prime pumps on. If he remotely suspected insufficient fuel in the supply tanks, he would surely have put the transfer pumps on, and would certainly in my view have executed a powered landing on the remaining engine. He was so busy troubleshooting the first engine flameout, that the second caught him unawares, leading to the unsuccessful autorotation. Or at least, so the hypothesis goes.

[Art of flight]

I'm still with you, but are you saying this erroneous fuel indicated in the supply tanks would have to indicate more than the 48kgs for the Red warnings and more than the amount required for the amber cautions? I do think that's far too much for it to be anywhere near the flight time/fuel used calculation.

On the subject of Re-starting in flight, the evidence shows both the engine main switches being in the guarded flight position, indicating normal two engined flight, the Shed BUS was still in the guarded normal position indicating normal two engined flight. The warning system and Fadec log as investigated by the AAIB gave no signs of either engine having been re-lit once stopped. As Sid said a while ago, it will be interesting to find out if the throttles were out of the neutral gates?

[falcon900]

Art,
I dont have any basis for querying the red warnings, and accept them as genuine. I believe however that the gauges still showed more fuel than the corresponding amount in the supply tanks, and that the yellow cautions were not triggered, hence confusing the pilot as to the fuel state, and sadly leading him to believe the gauges rather than the red lights.
I accept your point about the restart attempt, or lack of it. I was clutching at straws to explain the prime pump switch positions.
I am finding it hard to believe that when he contacted ATC, not only were the red lights on, but he had an engine out, but the four minutes between the call to ATC and the end of the flight would suggest just that. Unless of course the contents of the supply tanks were not as intended, and were much closer to being equal, leading to two flame outs in quick succession. I posted previously about the tanks emptying over the fence and through the supply pipe orifice in unequal amounts, and how the transfer pumps could only fill them symetrically. With the transfer pumps off, the actual fuel quantities are unlikely to be "as designed" if the aircraft had been manoeuvering a lot, with much attendant spillage.

[catch21]

I still think there may be a scenario in which one supply tank over reads. What do you think?
I just can't envisage prolonged flight at the back end of endurance with a dark CAD.