Police helicopter crashes onto Glasgow pub
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Just done a quick calculation. 400kgs fuel, less ~76kg recovered post crash. 324kgs used in about 110 minutes, so just about 3kg/min average.
Supply tanks generate low fuel warnings at ~30kg in each tank, so with ~60kg there is roughly 20 minutes before flame out on each engine (with a couple of minutes between due to deliberate tank size design).
Those fuel captions must have been lit for that length of time, or a bit longer if in transit rather than in hover where fuel flow would be a bit higher.
Would the two police officers in the crew have observed and understood the fuel captions? Could they see them? I can't imagine they regularly sat and watched the warning display all lit up, so they ought to have known something was not right. Under those circumstances would they not have asked a question or reported it to their colleagues in the control room?
Puzzling!
Supply tanks generate low fuel warnings at ~30kg in each tank, so with ~60kg there is roughly 20 minutes before flame out on each engine (with a couple of minutes between due to deliberate tank size design).
Those fuel captions must have been lit for that length of time, or a bit longer if in transit rather than in hover where fuel flow would be a bit higher.
Would the two police officers in the crew have observed and understood the fuel captions? Could they see them? I can't imagine they regularly sat and watched the warning display all lit up, so they ought to have known something was not right. Under those circumstances would they not have asked a question or reported it to their colleagues in the control room?
Puzzling!
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Sorry Paco, we crossed posts as I edited to answer your question.
If Sid or Zorab are about perhaps they could nip out to the cab an try de-selecting the CAD and see what fuel indications are available on the VEMD?
If Sid or Zorab are about perhaps they could nip out to the cab an try de-selecting the CAD and see what fuel indications are available on the VEMD?
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Feathers
You're right, the TFOs would certainly have known the importance of all red captions and had something choice to say with both red fuel captions on! It's interesting that there is still no mention of what was being said on the airwave radios.
You're right, the TFOs would certainly have known the importance of all red captions and had something choice to say with both red fuel captions on! It's interesting that there is still no mention of what was being said on the airwave radios.
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If Sid or Zorab are about perhaps they could nip out to the cab an try de-selecting the CAD and see what fuel indications are available on the VEMD?
Page 3-44
http://helicopterindia.com/yahoo_sit...2.24193407.pdf
Procedure
1. OFF button on the CAD – Press
NOTE Pressing the OFF button removes power from the faulty lane. The CAU/FUEL
page takes priority over the ELEC/VEH page and appears automatically on the
lower VEMD screen. The ELEC/VEH page may be reselected on the lower
VEMD screen by pushing the SCROLL button on the VEMD. Pressing twice
causes SYSTEM STATUS page to appear. To return to the CAU/FUEL page,
press the SCROLL button again. In case of loss of SCROLL button, press RESET
button on VEMD to go back to default page.
1. OFF button on the CAD – Press
NOTE Pressing the OFF button removes power from the faulty lane. The CAU/FUEL
page takes priority over the ELEC/VEH page and appears automatically on the
lower VEMD screen. The ELEC/VEH page may be reselected on the lower
VEMD screen by pushing the SCROLL button on the VEMD. Pressing twice
causes SYSTEM STATUS page to appear. To return to the CAU/FUEL page,
press the SCROLL button again. In case of loss of SCROLL button, press RESET
button on VEMD to go back to default page.
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It seems I've answered the question - I found the 135 training manual on my hard drive (don't ask) and it says that the low fuel sensors are on the fuel sensors in the supply tanks - so yes, if there was some sort of blockage between the mains and supply tanks, I guess the pilot could be faced with contrary indications of enough fuel to get home (from the quantity transmitters in each tank) and low fuel (the low fuel sensors in the supply tanks). Is that covered in the training?
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The media is reporting this as a 'double engine failure' and anomalies in the displays, I don't know why!?
I'm not an aviator,(hence the probably incorrect terminology) but it's a short report and basically says there was fuel in the bulk tank, no fuel in the individual engine tanks, no or little fuel in the filters and the transfer pumps isolated, surely then its a question of why it was in that configuration. Unfortunately the level probes are smashed, though the pumps did work.
I've read the whole thread, the only question I have is I thought the engine tanks were deliberately different in capacity so that one turbine flamed out first giving the pilot time to react to whatever the issues are before the second one runs out of fuel
I used to design diesel power plants, similar bulk and day tank situation, though no need to transfer around to alter balance obviously.
ok, I lied, another question, as the engine tanks overflow back into the bulk tanks, could they empty in a dive condition back to the big tank? All the sketches are 2D, so I can't tell.
Not sure if there is some PR somewhere skewing the reporting, weird.
I'm not an aviator,(hence the probably incorrect terminology) but it's a short report and basically says there was fuel in the bulk tank, no fuel in the individual engine tanks, no or little fuel in the filters and the transfer pumps isolated, surely then its a question of why it was in that configuration. Unfortunately the level probes are smashed, though the pumps did work.
I've read the whole thread, the only question I have is I thought the engine tanks were deliberately different in capacity so that one turbine flamed out first giving the pilot time to react to whatever the issues are before the second one runs out of fuel
I used to design diesel power plants, similar bulk and day tank situation, though no need to transfer around to alter balance obviously.
ok, I lied, another question, as the engine tanks overflow back into the bulk tanks, could they empty in a dive condition back to the big tank? All the sketches are 2D, so I can't tell.
Not sure if there is some PR somewhere skewing the reporting, weird.
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"Not sure if there is some PR somewhere skewing the reporting, weird. "
I must admit I do have the feeling that things are being very carefully worded.
I must admit I do have the feeling that things are being very carefully worded.
so yes, if there was some sort of blockage between the mains and supply tanks, I guess the pilot could be faced with contrary indications of enough fuel to get home (from the quantity transmitters in each tank) and low fuel (the low fuel sensors in the supply tanks). Is that covered in the training?
A spokesman for Eurocopter, a unit of European aerospace and defence company EADS, said tests by Bond and two other EC135 operators in Europe found possible similar supply-tank fuel gauging errors that overestimated the fuel on board.
"The first analysis shows that the indication of the fuel quantity in the supply tanks could be overestimated," the company said in a statement.
"All crews should be aware that in the worst case a red warning "Low Fuel" could appear without any amber FUEL Caution before."
"The first analysis shows that the indication of the fuel quantity in the supply tanks could be overestimated," the company said in a statement.
"All crews should be aware that in the worst case a red warning "Low Fuel" could appear without any amber FUEL Caution before."
What prevents One from turning both Transfer Pumps "On" and leaving them "On". I can see the Prime Pumps being turned on for Engine Start then shut off after the Engines are running.
If One is seeing indications of the Supply Tanks being "low" on fuel....but indications of Fuel remaining in the Main Tank....experience tells me to turn the Transfer Pumps "ON"....both of them....and start looking for a parking place.
Now....let's accept the Fuel Quantity was showing more fuel than was actually present in any or all of the Tanks......just what was the amount of Fuel that it could be "over reporting"?
How does that variance play into the scenario?
The real question that needs answering.....which we all wish not to ask....is why did the Pilot not get the Collective Lever down, all the way down, and down in a timely manner and preserve enough Main Rotor RPM to facilitate a "Controlled" landing of some description?
The Pilot was very experienced and capable with no background of performance issues and was highly regarded by his Peers. He was a darn good guy and Pilot.
What happened that night that caused him to fall prey to the circumstances that he was unable to cope with the situation? Isn't that what we really want to know out of all this?
If One is seeing indications of the Supply Tanks being "low" on fuel....but indications of Fuel remaining in the Main Tank....experience tells me to turn the Transfer Pumps "ON"....both of them....and start looking for a parking place.
Now....let's accept the Fuel Quantity was showing more fuel than was actually present in any or all of the Tanks......just what was the amount of Fuel that it could be "over reporting"?
How does that variance play into the scenario?
The real question that needs answering.....which we all wish not to ask....is why did the Pilot not get the Collective Lever down, all the way down, and down in a timely manner and preserve enough Main Rotor RPM to facilitate a "Controlled" landing of some description?
The Pilot was very experienced and capable with no background of performance issues and was highly regarded by his Peers. He was a darn good guy and Pilot.
What happened that night that caused him to fall prey to the circumstances that he was unable to cope with the situation? Isn't that what we really want to know out of all this?
The design of the fuel system is crap,in that it require use of transfer pipes and pumps to fill the supply tanks.Other helos ,of earlier vintage all had low level gravity transfer pipes,with flapper valves to prevent back-flow,so even if the transfer pumps failed,you could get fuel to the EDPs.
Also, the position of the pump switches,in the roof panel leaves a lot to be desired,having to reach up to switch ON/OFF.Frequency of operation ,and that will depend on the operations,as in this case ,should have required a mod, to put them on the instrument panel,or central console.They should also have a `unique shape`/size for easy identification,even internal `beta` lights for `dark` cockpits.
Further ,the busbar shedding switches appear to be behind the pilot`s head,an admirable place to put them if the generators fail,even without engines failing,at night.I`m sure the extra equipment in Police ops would cause a loss of instrumentation at the most critical time,with the loss of a radar altimeter ,and a landing light,at night.They too,should be in a prominent,close to hand and again`beta` lit.
I admit I`m not familiar with the -135 in it`s role,only looking at the `panoramic `pics, so ,I will take any flak;I know folk will say that experience on type counts,but,it is nice if some odds are in your favour.
And ,a question; if this had happened in daylight,would the outcome have been the same....? or IMC..? If not ,,why.?
If crashing is inevitable,crash under control...
Also, the position of the pump switches,in the roof panel leaves a lot to be desired,having to reach up to switch ON/OFF.Frequency of operation ,and that will depend on the operations,as in this case ,should have required a mod, to put them on the instrument panel,or central console.They should also have a `unique shape`/size for easy identification,even internal `beta` lights for `dark` cockpits.
Further ,the busbar shedding switches appear to be behind the pilot`s head,an admirable place to put them if the generators fail,even without engines failing,at night.I`m sure the extra equipment in Police ops would cause a loss of instrumentation at the most critical time,with the loss of a radar altimeter ,and a landing light,at night.They too,should be in a prominent,close to hand and again`beta` lit.
I admit I`m not familiar with the -135 in it`s role,only looking at the `panoramic `pics, so ,I will take any flak;I know folk will say that experience on type counts,but,it is nice if some odds are in your favour.
And ,a question; if this had happened in daylight,would the outcome have been the same....? or IMC..? If not ,,why.?
If crashing is inevitable,crash under control...
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Is it possible that, having had one engine fail, he was looking up and back to load shed, with his hand off the collective, when the second engine unexpectedly failed?
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Absolutely possible, as are a number of other cockpit scenarios.
The one of real interest is why both transfer pumps were selected OFF. Firstly, I'm not keen on a fuel system that needs playing with at low fuel levels as one goes from hover to forward flight and back again. Second, the layout of the system is obviously less than best practice for the police role where changes from hover to forward flight and back while exploiting fuel limits to the edge to get the task done must be commonplace.
Does anyone with type experience know if the intermittent FUEL LOW warnings on no1 and single continuous warning on No2 are typical? It does seem odd to me that the two systems would behave so differently. Is there anything to be drawn from that?
The one of real interest is why both transfer pumps were selected OFF. Firstly, I'm not keen on a fuel system that needs playing with at low fuel levels as one goes from hover to forward flight and back again. Second, the layout of the system is obviously less than best practice for the police role where changes from hover to forward flight and back while exploiting fuel limits to the edge to get the task done must be commonplace.
Does anyone with type experience know if the intermittent FUEL LOW warnings on no1 and single continuous warning on No2 are typical? It does seem odd to me that the two systems would behave so differently. Is there anything to be drawn from that?
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Not a pilot, so ignore me if you wish.
After reading the special report I am struck by the number of actions the pilot did not take, fuel transfer switches, shed bus, enter autorotation. It is almost as though he was unable to act for whatever reason.
Was the helicopter on autopilot? Is there any evidence of any human pilot action?
Apologies if this has already been covered.
After reading the special report I am struck by the number of actions the pilot did not take, fuel transfer switches, shed bus, enter autorotation. It is almost as though he was unable to act for whatever reason.
Was the helicopter on autopilot? Is there any evidence of any human pilot action?
Apologies if this has already been covered.
According to the report, NVGs were carried by all crew members: can a UK police pilot advise whether they would have been worn and used as a matter of SOPs?
If so, how would they have restricted the view in the cockpit of the fuel switches and particularly looking up and back for the load shed? If worn and functioning it also would make the loss of landing lamp a moot point, and I see the loss of radalt as similarly minor since all attention would be outside for flying. Had there been any Nr to fly with.
If so, how would they have restricted the view in the cockpit of the fuel switches and particularly looking up and back for the load shed? If worn and functioning it also would make the loss of landing lamp a moot point, and I see the loss of radalt as similarly minor since all attention would be outside for flying. Had there been any Nr to fly with.
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Lack of action? It's very hard to say. Without timings or recordings of data or voice it might always be speculative. The whole mess might have occurred in only a few seconds. Sudden shocking unserviceability, and failed juggling leads to an unavoidable accident.
If the warning system records warnings being registered, but potentially invisible or under visible because the display was failed, then an oversight on the pump settings could occur, they could both stay off, and the fuel exhausts without giving the familiar lights.
I understand that the pumps can't be run dry, hence the need to select the pumps on and off. However, I'm not clear why the manufacturer can't automate this function. Allow the pumps to run whenever the aircraft is powered: when they sense they're submerged they pump, and when they sense that they're dry they turn off. Mr Sixtoo suggests that it doesn't seem that the need to turn off the main tank pumps when the main tank is almost empty, or to turn off front/rear when hovering/cruising adds anything to the pilot's knowledge of what's going on, and just provides a potential opportunity to get caught out. I tend to agree.
If the warning system records warnings being registered, but potentially invisible or under visible because the display was failed, then an oversight on the pump settings could occur, they could both stay off, and the fuel exhausts without giving the familiar lights.
I understand that the pumps can't be run dry, hence the need to select the pumps on and off. However, I'm not clear why the manufacturer can't automate this function. Allow the pumps to run whenever the aircraft is powered: when they sense they're submerged they pump, and when they sense that they're dry they turn off. Mr Sixtoo suggests that it doesn't seem that the need to turn off the main tank pumps when the main tank is almost empty, or to turn off front/rear when hovering/cruising adds anything to the pilot's knowledge of what's going on, and just provides a potential opportunity to get caught out. I tend to agree.
'm also guessing that there was not sufficient time for the pilot to react to the double flame out and as a result the RRPM decayed to an un-recoverable level resulting in the crash.
This just about sums up the case. The pilot simply didn't react correctly to a sequential double engine failure. Brutally; he lost Nr which can only happen by mishandling and crashed.
What more needs to be said?
I know. it ain't popular. But that's clearly what happened.
Be he a great guy, a superb pilot and highly respected by his peers doesn't make him infallible as the facts show, just as the crew that flew the Chinook into the Mull of Kintyre or the A109 into a crane in fog in London were all "good guys", superb pilots" and "couldn't possibly have" done what all the evidence clearly shows they did....
Sorry, human fallibility is the cause, nowt else. As ever.
Last edited by Wageslave; 14th Feb 2014 at 21:15.
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And if it can happen to one who has been widely considered as of above average skill, then is it not a good idea to pay close attention to the causes that lead him and his colleagues to die along with the passers by?
Does brushing it off as a screw-up, based on just this brief factual note from the AAIB, advance the cause of flying safely or reduce the chance of it happening again?
Does brushing it off as a screw-up, based on just this brief factual note from the AAIB, advance the cause of flying safely or reduce the chance of it happening again?
Last edited by awblain; 14th Feb 2014 at 23:01.