Police helicopter crashes onto Glasgow pub

[Pittsextra]

Optimistic, as in if you have 2 differing indications of fuel you believe the higher value?

What planet are you on?

Read what is written. I wrote :-

Even if the fuel gauge suggests you have fuel in the tank it seems a dumb trade to believe one instrument over another and allow yourself to be more optimistic

As in if the fuel gauge suggests you have a full tank but there is a Red "low fuel" warning. I think most would assume the worse.

What planet are you on?

[SASless]

So....are we all agreed that upon the first Red Fuel Low Warning Light illuminating in the Glasgow Aircraft that night....the procedure would have been to land within Ten Minutes?

Do we have any indication those particular Warning Lights were NOT working that night?

If those lights illuminated as advertised....and the aircraft flew for Ten more minutes....how much fuel would have been in the Supply Tanks (in Theory)?

Assuming, based upon the lack of comments about any malfunction, or fuel problems/shortage by the Pilot to ATC or Police Ops....are we correct to assume the Fuel Quantity Indication system was operating normally?

We don't know what was told to Police Ops at all do we?

We are beginning to see problems in the EC-135 Fuel System and related systems as shown by all the comments and reports of AAIB testing.

We are having discussions about flying for Ten Minutes after a Fuel Low Warning illuminates, in an aircraft that seems to have Quantity Indication Issues, and a potential problem with confusing Cockpit display of fuel system status when malfunctions occur.

The old time method of calculating fuel quantity, consumption, and determining a finite fuel endurance might not be useful as not all the fuel from the Main Tank might be transferred to the Supply Tanks for use by the Engines.

Y'all really want to fly on into the Supply Tanks a full Ten Minutes past the Fuel Low Warning Light illuminating? Really?

You think that is a sound practice....one that errs on the side of Safety to the avoidance of unnecessary risk? Really?

[SilsoeSid]

If I may explain a few things;

There is no mention here about the term 'Alarm'. There are only 2 terms relevant here, 'Warning' and 'Caution'. The definitions of those terms in relation to the EC 135 are clearly explained in the Flight Manual and have been quoted recently.

When the Warning for low fuel comes on, you are instructed to Land Within 10 minutes. In theory, in the worst case scenario, with the lights coming on at 26 kgs in number 1 & 22 kgs in number 2 supply tanks, if you landed after exactly 10 minutes flying time, you would have 5 minutes for number 1 and 3 minutes for number 2 remaining before they flamed out.

(200 kgs/hr; 3.33 kgs/min; each engine on its own supply 1.7 kgs/min)

Here's a pic, thanks to the wonders of the internet;

In the case of SPAO, if we are to assume that with all the displays working correctly & telling the correct information this is what was presented.
Why on Earth would anyone fly for 15 minutes with a system showing you this Christmas tree full of cautions and warnings, after at least 4 gongs and at least 5 caution/master cautions, when you know that you should land within 10?



(Please realise that in SPAO the main tank should have been reading 96-76 kgs, the green PITOT advisory would be on, it was night and 2 qualified police observers would also be able to see the displays and more than likely would have read the FRC's)

I've tried to be helpful, cooperative and explain the facts and details as clearly as possible, but it seems as though some just want an argument.

I think this last pic is about all I can bring to the party.
'Til the next report then ...

[FlightSpanner]

I still believe the reds came on during the last task, whilst the supplies were still showing full, it was then terminated but not enough fuel remained in the supply tanks.

Other than a CAD fail surely there is no other logical explanation. I'll wait to be corrected when the final report is out.

FS

[catch21]

SS: In the case of SPAO, if we are to assume that with all the displays working correctly & telling the correct information this is what was presented.
Why on Earth would anyone fly for 15 minutes with a system showing you this Christmas tree full of cautions and warnings, after at least 4 gongs and at least 5 caution/master cautions, when you know that you should land within 10?

Well, frankly you wouldn't that's clear.

Many other possibilities presumably exist, including a blank CAD having failed, or the fuel contents over-reading.

Several questions come to mind, if the CAD was blank why would anyone push their flight time beyond the 1hr30min? You would know you are not going to get any cautions. That "continue-to-fly" strategy doesn't make much sense.

The second set of questions is over the Low Fuel 1 & 2 warnings. Evidently they were triggered, but were they actually displayed, were they triggered at the correct level i.e. with 10mins fuel left and if so, why were they not acted upon?

[SASless]

if you landed after exactly 10 minutes flying time, you would have 5 minutes for number 1 and 3 minutes for number 2 remaining before they flamed out.

In theory.....assuming everything works as it should and fuel burn rates are right.

By my estimation....3 Minutes to spare is cutting it mighty close

I think I would just accept the first Red Fuel Low Warning as the first item on the Before Landing Checklist.

Lonewolf_50 pointed this article out to me.....

Land the Damn Helicopter | Flying Magazine

The last paragraph sums it up!

[Feathers McGraw]

Something made me look quite hard at Sid's pictures of the fuel display, and I find that there's something bothering me.

The display for the supply tanks has the black rectangle with the digital quantity very close to the top of the blue 'fuel' indication area. The thin blue strip around the outside of this box is not very obvious.

The difference between the levels being full and roughly half full is thus only the presence or lack of these thin blue stripes, together with a change in a couple of small digital values.

Does this make the supply tank gauges prone to misinterpretation? I'm thinking that with 76kg showing in the main (assuming it was) that a reducing level in each supply tank could result in enough blue showing that it appears normal with the exception of those narrow blue areas at the top and sides.

I would say that it would be more sensible for the digital display in the black rectangle to be placed so that a much larger area of blue shows above it with full supply tanks. When that blue area starts reducing it would be a visual cue well before any low fuel warning occurs.

Of course, if the display were blank in this crash this suggestion is irrelevant, but I think my question is valid in terms of making the display of fuel levels in the supply tanks more obvious.

[John Eacott]

SS (and other 135 drivers)

How much of this information becomes degraded when seen through NVGs eg the colours being discussed, the 'fine lines', etc. Are the overhead switches free to move if knocked by helmet/nvg rig, or are they 'locked' and have to be lifted to operate?

[that chinese fella]

Hi John,

You don't look at the instrument panel through the NVG's, they don't focus on things that close, so you have to look under them. Its not a problem, but its why I personally have the goggles adjusted all the way forward so I don't have to lift my head to scan either the instruments, mapping or FLIR monitors.

The 4 pump switches aren't of the locked or guarded type.

TCF

[AlphaZuluRomeo]

Originally Posted by John Eacott

How much of this information becomes degraded when seen through NVGs eg the colours being discussed, the 'fine lines', etc.

I'm not a "135 driver" but I still feel confident enough to answer that

Bottom and simple line is: you shouldn't do that. Indeed:
- You see outside by looking through NVGs.
- But you see inside by looking below NVG tubes.

Why? Well, to see outside (which is the point), NVGs have to be focused to infinity. Hence, if you look inside the cockpit through them, it'll be (very) blurry.

Last but not least, displays such as CAD & co are meant to be "black" when seen through NVGs (if set to NVG-compatible mode), to avoid glare.

[edit] oops, didn't see that that chinese fella had already answered... sorry, I must have read part of the topic with NVGs on... (lame excuse, I know)

[AlphaZuluRomeo]

Originally Posted by DAPT

Fuel level could be configured to change to amber or red depending upon caution or warning light illuminated

Err... Who could configure that? Are you saying the crew could (should?)
AFAIK, in 135s fuel level is always shown in blue (+ a FUEL caution exists on the CAD Misc part)
OTOH in 145s fuel level is shown in blue (if normal) or yellow (if caution level or below) (and there is no "separate" FUEL caution on the 145).

[mickjoebill]

Quote:
mickjoebill;

I can't find any reference in flight manuals to unusable fuel with pumps off.
Perhaps clicking on this will help

First result, pages 85 & 86

You've proved my point there is no advice on page 85 or 86 on fuel available with pumps turned off.

Page 85 and 86 does state 75kg unusable in hover reduced to 7kg at 80knots, could this lead pilots to assume the supply tanks are gravity fed?




Mickjoebill

[John Eacott]

Re the degradation associated with NVGs, I should have worded my query a bit better! The machines that I've flown that are NVG compatible have had filters over flat screen displays to make them usable with NVGs: this filter has made them almost monochrome and difficult to read.

Would the same treatment to the 135 display create a monochrome/reduced colour effect?

[that chinese fella]

Would the same treatment to the 135 display create a monochrome/reduced colour effect?

Not in the EC135 I fly on NVG. It has the factory NVG mod BTW.

FWIW, I consider the 135 fuel system and its associated displays, cautions/warnings, pump switch operation, location and design quite logical.

It certainly is no worse than many aircraft before it, and in many ways, better.

[that chinese fella]

could this lead pilots to assume the supply tanks are gravity fed?

Only if your initial endorsement training was pitiful, any subsequent training and checking on type inadequate and your own professionalism, to continue to revise your knowledge and learn as much as you can about the aircraft you fly in, is sorely lacking.

Other than that, to answer your question, if your a complete numpty, then sure one could assume that…..

[mickjoebill]

Only if your initial endorsement training was pitiful, any subsequent training and checking on type inadequate and your own professionalism, to continue to revise your knowledge and learn as much as you can about the aircraft you fly in, is sorely lacking.

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


Mickjoebill

[Cows getting bigger]

OK, the engines stopped because of fuel starvation. The tech side may or may not be able to figure whether the pilot was presented with an accurate fuel state.

Surely another elephant in the room is the efficacy of the autorotation, if indeed there was one?

[Senior Pilot]

Originally Posted by Cows getting bigger

OK, the engines stopped because of fuel starvation. The tech side may or may not be able to figure whether the pilot was presented with an accurate fuel state.

Surely another elephant in the room is the efficacy of the autorotation, if indeed there was one?

Already discussed, and a thread dedicated to it.

[AtomKraft]

In summary, fuel starvation?

Might have flown a bit longer with the appropriate pumps selected ON?

Is that about it?

[RVDT]

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

At least.

In fact up to 44% could be unusable with the XFR pumps OFF.