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Police helicopter crashes onto Glasgow pub

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Police helicopter crashes onto Glasgow pub

Old 23rd Feb 2014, 01:14
  #2361 (permalink)  
 
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SilsoeSid
An excellent demonstration. Many thanks for the videos. Just goes to show how a "foolproof" system can lead one completely up the garden path. Well done!
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Old 23rd Feb 2014, 01:43
  #2362 (permalink)  
 
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AAIB called you yet Sid?
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Old 23rd Feb 2014, 06:35
  #2363 (permalink)  
 
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Agreed great vids thanks.

What's the emergency checklist procedure for CAD fail in respect of precautionary landings and crosschecking switch selections?

The police radio tapes must surely contain something informative?
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Old 23rd Feb 2014, 08:14
  #2364 (permalink)  
 
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many thanks for the vids, forget about Olympia, somebody deserves a Gold Medal here! Somehow I am not surprised about this outcome.
If the CAD and/or cautions have been messing around, would you INSTANTLY firmly believe in the RED LOW FUEL warning? Especially you know there 'must' be more in the tank! Base is in sight, crystal clear air from a northerly wind, you can go straight in, scenery looks like you can grip the Science Center with the tower and beacon opposite the helipad with your hand. Then a big shock when first engine flames out (just at the very very wrong moment right before crossing the city centre with glass roofs of shopping malls and train stations). Total disbelieve and confusion, not more, not less? Just fuel for one minute more, ore one minute less could have shown a heli on the pad or somewhere else safe on the ground. I am not looking for excuses, but the pilot would not have been aware how displays and timing was playing against him at that otherwise perfect night? Obviously he was not aware of the pump settings either by direct visual cross check.

Last edited by rantanplane; 23rd Feb 2014 at 08:43. Reason: just waking up
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Old 23rd Feb 2014, 08:25
  #2365 (permalink)  
 
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SilsoeSid:
Very cool vids, thx for sharing, love your work
What I really like in your demos is that you to them at night, thereby perfectly simulating the possible glasgow display scenarios!

What strikes me though, is that we clearly see the fuel display elegantly jump to the backup screen, but from then on lacking the data? So the "backup function" is not a backup (lacking all vital data) but some very expensive kind of "warning, display is down" light

Pretending to use another still functioning display, thereby insinuating redundancy, while in reality there is none, constitutes a grossly misleading user interface. All that screen real estate devoted to saying "no data for you", am I missing something
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Old 23rd Feb 2014, 08:59
  #2366 (permalink)  
 
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henry, on a Friday night the east part of Glasgow is not really a safe place to land with a police helicopter - even if your landing was safe. The crowd is drunk at that time of the day, and some guys of that crowd had a very frustrating life.. kids have been throwing stones at rescue service vehicles in areas like Glasgow East End..so you have been just chasing these delinquents, would you land on a bad illuminated car park or somewhere completely in the dark if you are not sure its already an absolute emergency?
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Old 23rd Feb 2014, 09:12
  #2367 (permalink)  
 
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Thanks Sid, sterling work.

The manufacturers have a lot of information to fit on to those VEMD graphics, they obviously had to decide what THEY thought was imortant weighed against statistical data of failure rates of components etc...Police pilots know that the VEMD representation of limited CAD information after failure is just that, limited. I've always thought the lack of fuel information and cautions was a big mistake which is why I alluded to it earlier in the thread and asked people to refrain from just jumping in without all the facts. Sid has guided you through the system and now revealed what we've known for years, when it's working it's simple, when bits start playing up it really does become a pain. Some will obviously say why continue to fly an aircraft with faults? My answer is that Police (and AA) flying in the UK is still really operating on a shoestring budget. It has grown up on a basis of one aircraft per unit (Met excepted) with no spare aircraft. You do everything in your power to get that aircraft to that task. There is a document called the MMEL which lists the acceptable faults that can be carried, it contains a surprising catalogue of bits that can be 'inoperative' for police operations, including much of the fuel indication system.

As I said earlier, I know of one aircraft (on the ground) that has failed to display any red warnings as the fuel emptied to zero. Combine that with a CAD faiure and what you've got left as a fuel warning system is the wind up clock.

Last edited by Art of flight; 23rd Feb 2014 at 09:25.
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Old 23rd Feb 2014, 09:15
  #2368 (permalink)  
 
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Great videos Sid, is there any situation in flight that would demand Xfer pumps off and Prime on? I can't think of any. With that in mind maybe a CAD failure at first power up could (my opinion only) explain why the pumps were left in this config.

Does the MMEL allow for departure with CAD failure or just continued flight?

Can I also ask what the RFM procedure is for a Red Low Fuel, and what you would do, check Xfer pumps?

FS
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Old 23rd Feb 2014, 09:44
  #2369 (permalink)  
 
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"is there any situation in flight that would demand Xfer pumps off and Prime on? I can't think of any"

Main tank empty or both Xfer pumps failed, Fuel Pressure caption on one or both engines.

........................

The MMEL indicates how many of each item is fitted, how many are reqired for dispatch, and the condition of use, ie

CAD power, 2 channels fitted, 1 required for dispatch, VFR flight only. same for VEMD.

...........................

Google EC135 RFM and you'll get all of the emergency captions and actions.
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Old 23rd Feb 2014, 10:10
  #2370 (permalink)  
 
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Thanks Art, makes sense.

However, the main tank was not empty and both Xfer pumps have been tested by the AAIB, so if CAD had failed then surely as a matter of importance you would leave the Xfer pumps on?

We know the reds came on, but as you stated in your previous post you have witnessed failures of these which shows unreliability of the system, perhaps they came on too late and 10 mins was not available! The testing you saw did they run till indicated zero or flameout? Means the difference between a faulty low level device or a faulty probe system.

I'm trying to work out why the prime pumps would be switched purposely on, or if they were left on. If say 2 mins aftert the red came on one engine started showing symptoms of fuel starvation maybe the prime pumps were activated?

FS
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Old 23rd Feb 2014, 10:42
  #2371 (permalink)  
 
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"However, the main tank was not empty and both Xfer pumps have been tested by the AAIB, so if CAD had failed then surely as a matter of importance you would leave the Xfer pumps on?"

But then you'd be disregarding the drill in the RFM.....

.....................................

"The testing you saw did they run till indicated zero or flameout? Means the difference between a faulty low level device or a faulty probe system."

It wasn't a test, just a request from the engineers to run the supply tanks to minimum to allow them not to have to drain too much into a bucket before inspecting the tanks so it was a surprise to all that the warnings didn't come on and they may have been faulty for months or years prior to that.

.......................................

"If say 2 mins aftert the red came on one engine started showing symptoms of fuel starvation maybe the prime pumps were activated?"

Not sure about the symptoms, in my experience, once the flame goes out it's out, ie...instant.

IMHO I think the 4 pump switches were selected by simple mistake, but I have absolutely no proof, I've done it myself in the past but have picked up MY error on the CAD straight away.

As a simple test, stick a post-it note to the car headlining above your left shoulder with a drawn on diagram of 4 switches and labels, put on your reading specs and a baseball cap (after dark with the instrument lights on)and try to read it (driving at the same time would not be a good idea).
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Old 23rd Feb 2014, 11:38
  #2372 (permalink)  
 
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CAD failure - no audit trail

terrific effort Sid. Are we saying in the event of a CAD failure in flight, no audit trail or footprints would be left for investigators to know of that?

I believe the Warning Unit holds the last 31 events in memory and here is the extract from the report for reference:

"The Warning Unit has provided information on the order in which warnings were triggered
during the flight but not when they occurred. The unit recorded the normal warnings
associated with starting the helicopter, followed by a warning free status. It subsequently
recorded intermittent LOW FUEL 1 warnings for the left fuel supply tank, then a permanent
LOW FUEL 2 warning for the right fuel supply tank. This was followed by a further
temporary LOW FUEL 1 warning, before it became permanent for the remainder of the
flight. These LOW FUEL warnings are triggered by thermal sensors in the supply tanks.
For this helicopter build configuration, they indicate when there is approximately 32 kg and
28 kg of fuel remaining in the left and right supply tanks, respectively. On receipt of these
warnings, the manufacturer’s flight manual for the helicopter instructs the pilot to ‘LAND
WITHIN 10 MINUTES’.
An alarm gong was also recorded followed by intermittent warnings relating to low rotor
rpm. The penultimate warning recorded related to the battery discharging, which occurs
when there is insufficient engine-driven generator power. The last warning related to an
autopilot system failure. Investigation into the possible causes for the individual warnings
is continuing."
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Old 23rd Feb 2014, 12:53
  #2373 (permalink)  
 
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Agreed Henry, IF the cad had completely failed you wouldn't know it wasn't empty. Until we know more about the error code then it is a big IF.

CAD fail, Red Low Fuel would surely make anyone with system knowledge check the Xfer pumps are on, regardless of RFM procedure.

Perhaps that was the trigger, and as Art guesses the wrong pumps were turned on whilst his mind was on where to land.

Art - Do you know how much Fuel the engineers physically drained from the supply tanks? I'm guessing the supply QTY was showing zero?

Disregarding the drill in the RFM? What is the drill for CAD failure and subsequent loss of fuel qty indications? Maybe wrongly it assumes Xfer pumps are on.

FS
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Old 23rd Feb 2014, 13:58
  #2374 (permalink)  
 
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I tend to agree that in that situation the choice of landing area would probably not include an appraisal of much beyond the actual landing of the aircraft. Part of even a hurried landing will be a call to control by the TFO to specify the location and nature of the landing and any assistance required.
The drill for CAD failure is to switch off the power to the CAD, this may re-set it, if not, then monitor the VEMD pages for cautions. Implicit would be the fact that cautions such as Fuel QTY Degrade/Fail will not be availible so the flight time and clock would be used to calculate time remaining. The TFO will assist the pilot by reading out the relevant pages of the emergency checklist as required.
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Old 23rd Feb 2014, 18:40
  #2375 (permalink)  
 
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I tend to agree that in that situation the choice of landing area would probably not include an appraisal of much beyond the actual landing of the aircraft. Part of even a hurried landing will be a call to control by the TFO to specify the location and nature of the landing and any assistance required.
With talk of 'hurried landing' in various ways, I can't remember seeing any comments on how busy the roads in the area were at that time of night. I would have thought there would still be quite a lot of traffic.
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Old 23rd Feb 2014, 19:21
  #2376 (permalink)  

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After waking this early evening with a pressing thought, I've just checked my concern and in both the situations of;
a.The transfer pumps running dry or being switched off, and
b. The prime pumps being switched on,
They DO NOT initiate the caution audio, regardless of the CAD condition.

Interesting that the book states; "Pumps must be OFF during normal flight operations", yet doesn't warrant the audio!
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Old 23rd Feb 2014, 19:47
  #2377 (permalink)  
 
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After the tragic East Midlands accident in the mid nineties, when a Police AS355 crashed just after taking off from a remote site, and no one knew that the A/C had gone down. The CAA made pre and post take off and landing calls to the operational Control room mandatory.

Very little seems to have been released by the police as to what contact they had with that aircraft (a) during the mission as a whole and (b) round about the time of the accident. One thing is clear and that is that had the accident not happened, then that aircraft would have been landing very soon after. Therefore, I would have expected such preliminary contact to have already taken place. This has not been subject to any comment as far as I can see.

tigerfish
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Old 24th Feb 2014, 00:40
  #2378 (permalink)  

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Tf;

Not sure how they work North of the border, but under NPAS the SOP is for the TFO to give dispatch & flt following a call when about to lift and also call 2 mins before landing. These are followed up by the despatch room 'Oop North'. There are also 15 minute Ops normal calls throughout the flight regardless of operating area.

I'd imagine any registered/recorded police calls will be in the final report, as will the more accurate GPS tracks etc. I asked the question last night, 'If one of the officers was to try and make a call on the Airwave/Scottish system radio but it didn't make the connection as is the case a lot of the time, would the attempt to call be registered'.
'Probably' was the best we could come up with, but only after investigation by the net operator.
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Old 24th Feb 2014, 08:13
  #2379 (permalink)  
 
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CAD failure

According to the AAIB, the events log goes back as far as "normal cautions associated with startup" and continues through to the final moments. If there had been a fault with the CAD,surely the pilot would have recycled the unit, as per the manual, and this would have either cleared the memory of events, or been recorded as one?
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Old 24th Feb 2014, 08:46
  #2380 (permalink)  
 
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Falcon,
The "normal warnings associated with start up" appear on the warning panel not on the CAD.
Warning panel = RED
CAD = Amber.

Last edited by Fortyodd2; 24th Feb 2014 at 09:01.
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