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Police helicopter crashes onto Glasgow pub

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Police helicopter crashes onto Glasgow pub

Old 19th Dec 2013, 14:50
  #1381 (permalink)  
 
Join Date: Dec 2006
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ROBIN 400

is it remotely possible that both supply tanks exhausted at approximately the same time
Dealing only with know facts......there is a slight difference in the contents of one supply tank from the other. I beleive this equates to about 1-2 minutes of cruise endurance. Some on this thread have inferred from this fact that, as the Supply Tank contents decrease towards zero, one engine will definitley flame out first...followed some time later by the second engine flaming out.

The reality is that at the point the main tank feed stopped (for whatever reason):

1. AC attitude (especially lateral) may cause the supply tanks contents to be slightly different.
2. Despite both engines being FADEC controlled, slight difference in fuel burn may be apparent.

Therefore, in answer to your question, yes, in theory it could be possible for both engines to flame-out at the same time. However the chance of this happening would be statistically very small.
More significantly, the chance of the events coming close together is more probable than simple comparing the differences in static supply tank useable contents and assuming a definitive time based split in the events occurring.

Hope this makes some sense.
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Old 19th Dec 2013, 15:35
  #1382 (permalink)  
 
Join Date: Dec 2013
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Hi Paracrap

It's a shame my piece on BBC News was so cringeworthy for you Paracrap. You see I called in to the BBC because I (yes....I....not a pilot, not even in my capacity as a tech...just in my capacity as a normal, caring person)....I was getting really upset! I'm sorry I made you cringe but my intentions were nothing but honest and noble.

I was getting really upset because BBC News were basically pinning it on your brother pilot. It felt to me that he was being hung, drawn and quartered by the Beeb by inference and above all that NO-ONE was offering any facts of substance passed, 'Should the pilot have done this? Should the pilot have done that'. Why didn't he...etc. Basically they didn't have a clue.

I'm not for a second saying that I do....but I am AWARE how these machines work both fixed and rotary and NEVER claimed to be an expert. Yeah I got it wrong. But so ******* what? It was about informing the BBC that thisd guy was maybe under soooo much pressure and still had a job to do e.g. save his charges and try not to hurt anyone when he landed. Poor soul.

So I phoned up to tell them that. Based on two small eye witness accounts as reported by the Beeb and on analysis of the pics (upright / intact nature of airframe and other details....no crater) I knew I could provide something of SOME substance that would HOPEFULLY stop the ridiculous statements the Beeb were making and maybe add some perspective to what kind of pressures the pilot was under.

Having worked on sims I've sat off-console during sorties and flew untutored for maybe 300 hours (had to test the system once it was repaired etc). Simulators are all about procedure and I know that you guys get put through your paces and put under INTENSE pressure during a sim sortie. I've witnessed pilots under incredible pressure perform with aplomb. This kind of training is ALL FOR THE GOOD. I have nothing but respect for you guys. Enough respect to ensure that the pilot in question wasn't proven guilty before the AAIB even managed to catch a train to Glasgow. Yeah mate, if it wasn't bad enough that all those poor folks were hurt / killed the 24 hour rolling crud service had to fill the airtime with some rubbish. Well theirs was just insulting. At least I could proffer some possibilities based on my LIMITED knowledge. Which I did. Fortunately they had a trainee helicopter pilot (I think) on a short time after me adding a lot more substance. Which was great! At no point did I pretend to be something I was not.

So what did you do, Paracrap? Did you just sit there and cringe? Did you not get so hacked off with my off-target assessment that you reached for the phone to help add clarity? Help exonerate your pilot brother before the Beeb pinned it all on him. No, you just decided to sit their and moan about it and criticise those who weren't coming up to scratch? You could have provided so much clarity, Paracrap (and the others who didn't lift a finger to provide profession guidance to the BBC...and you had the knowledge), but you decided to become just another faceless internet asshole and pass judgement....just like the Beeb were doing to your brother pilot by inference.

Your Sincerely
Andy Dixon

[email protected]
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Old 19th Dec 2013, 18:35
  #1383 (permalink)  
 
Join Date: Sep 2005
Location: Scotland
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Police helicopter crashes onto Glasgow pub

Cabby,
I tend to agree with you re engine out and pan call to Glasgow. The absence of any reported call only adds weight to suspicion that whatever occurred it was a very rapid deterioration. There were 2 other crew each with police radio access. This surely is a case of being pecked to bits by a flock of ducks, as opposed to being eaten by a crocodile!
Eurocopter are working with AAIB with various component manufacturers, as is normal. Any indication if a fleet wide problem would be reported as soon as can be verified.
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Old 19th Dec 2013, 19:04
  #1384 (permalink)  
 
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AoF, thanks for filling in my blanks as I was to quick. There are no caution for us pumps. Only when swithced off.

What Im saying is the overflow (both ways) correctly fills up the supply up to a point when transfer pumps are off or check valve us. As you know the pumps have a dry operating time of Approx. 20min. Multiple dryruns could have damaged the pumps over time. Anyway, this means it will still be fuel left in the main tank even if supply tanks are running empty.

AC attitude does of course make a difference, but if for whatever reason both transfer tanks are off, what is then transfering fuel to the supply tanks?
Prime pumps are in the supply tanks and makes no difference if supply tanks are empty.

I know this is a long shot, and it is unlikely, but system failure do occur and is a possible explanation to something happening so quick.
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Old 19th Dec 2013, 19:47
  #1385 (permalink)  
 
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Safety Flight,
"There are no caution for us pumps. Only when swithced off".

That is incorrect. There are cautions and they are driven by an "Amps monitor".
Essentially, if the pump is functioning normally then it should be drawing 1.5 to 6 Amps of current. If it pulling less than 1.5 amps then it has no fuel to pump and the caption will appear after 2 mins - the delay is to stop it cycling. If it is drawing no amps, it has failed or has been switched off - caption appears. If it is drawing more than 6 Amps then the fuel line is blocked, the caption appears.
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Old 19th Dec 2013, 20:27
  #1386 (permalink)  
 
Join Date: Dec 2013
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It is with great apprehension I make my first post on this incredible forum.

In my capacity of newby and recently qualified PPL(h) I have read and been glued to this entire conversation. I am amazed by the interaction between professionals, speculators and all other inputs equally.

The tragedy that occurred on that fateful evening has touched me and given me much to reflect on.

I have no theories and certainly no hidden agenda.

I might add that I had the misfortune of a fuel related engine failure during my training(not suggesting this is the cause) and the events that unfolded were indeed very quick to occur, entirely without warning and the severity of it took a few days to sink in.

My thoughts and condolences go out to everybody affected by this tragic event, and sincerely hope that any findings can bring about any relevant improvements to safety in the future.

Thank you P A
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Old 20th Dec 2013, 01:10
  #1387 (permalink)  
 
Join Date: Mar 2013
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Welcome.

The cause must be known.

As we all know safety is paramount, depending on who is footing the

bill.

Give it 2 to 3 years before things become open.

Sad but true.
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Old 20th Dec 2013, 01:52
  #1388 (permalink)  
 
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Tail Rotor failure ... retard engines

There is quite a large body of the piloting community who would close the engine(s) as a first for suspected tail rotor failures, the best way to stop the torque is just to lower the lever initially. As the majority of ppruners know well the engine(s) if time and opportunity arises can be used for yaw control later. BUT closing 'throttles' first has often been fatal...


and anyway most suspected tailrotor failures aren't real failures anyway...
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Old 20th Dec 2013, 13:47
  #1389 (permalink)  
 
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Lifted from the "Eurocopter grounds..." thread and posted just now.
Politically not correct, "Bond grounds..."

skadi
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Old 20th Dec 2013, 14:01
  #1390 (permalink)  
 
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There is quite a large body of the piloting community who would close the engine(s) as a first for suspected tail rotor failures, the best way to stop the torque is just to lower the lever initially.
Why?
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Old 20th Dec 2013, 14:22
  #1391 (permalink)  
 
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Lone......remember the way Pedals need to be moved upon lowering the Collective? That Sir....is a small clue!

Most RFM's state that in the Emergency Procedures for Tail Rotor Failures (Loss of Thrust and/or Loss of Components).

For other Tail Rotor Failure Modes.....moving the Collective may not be as important or as critical.
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Old 20th Dec 2013, 15:12
  #1392 (permalink)  
 
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Flight Manual Revision

EASA EAD 2013-0307-E: Eurocopter Deutschland EC 135 and EC 635 helicopters: Fuel - Fuel Monitoring and Fuel Quantity Indication - Flight Manual Revision | Publications | About the CAA
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Old 20th Dec 2013, 16:53
  #1393 (permalink)  
 
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Lower power with a tail-rotor failure?

Well, reducing power seems to make sense if there's now no tail rotor.

The emphasis shifts from powered flight to maintain a useful speed to maximizing controllability, and bringing aerodynamic forces to the fore, minimizing the torques that must be accommodated seems reasonable.

Landing, of one form or another, is imminent at this point, right? Typically that would be ideally at a lower speed than the cruising speed, and height has to be lost too, and so power is not an obviously helpful quantity.
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Old 20th Dec 2013, 19:26
  #1394 (permalink)  
 
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There is a fairly good video around which has been on here of a dude losing T/R drive in I think an S58. at low level in the hover whilst slinging. I don't think? he got the chance the roll power off, just down on the collective.

Mostly it seems that T/R failure will happen when it is loaded up, as it is then given the most chance to find something weak.
That was the case for me, just pulling up out of a clearing no A/S, bang, the front short shaft parted company with the T/R drive, the earth starts moving around the front window, on the second go round the earth was starting to blur, at that point I says to myself, self, you gotta chop that throttle and you gotta do it quick good boy.

It didn't stop the rotation, barely slowed it down, but I was able to see enough to steer to the centre of the only avbl spot, just about beneath me. Once again it was a high inertia rotor system (Bell 47 3B1) and lightly loaded, I chopped at about sixty feet straight down on the collective and wait, wait, one pull at the bottom and slightly bent the skids.

I had contemplated lowering the collective and flying away using only the thirty feet between me and the trees, clearly that showed itself quickly as not an option.

I would still contemplate lowering and flying away if I already had some A/S and plenty of height before throttle chop if I could.

Because of that emergency we practice T/R failures in the hover at four foot skid height, and at height, but not below 1500 AGL which becomes self evident after the first one.

In the high ones it seems the only way to get those "other aerodynamic forces" such as weathercock from a high A/S before the rotation becomes uncontrollable is to first chop the throttle. Then because there is now no power, Einstein predicts we must lower the collective and steer toward a nose low attitude, hey presto 60 knots quick time - rotation stops fairly quickly. One can then slowly increase power with collective to fly away to a good spot, no big deal.

It is a good procedure to steady up a hot head if they need steadying, if not an almost aerobatic manoeuvre, as the damn things will roll quite aways before stabilising in descent, so be warned, no loose articles, harness locked and tight.
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Old 20th Dec 2013, 21:02
  #1395 (permalink)  
 
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I think the video you mean may be this one:

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Old 20th Dec 2013, 21:13
  #1396 (permalink)  
 
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SAS, my why was about the bolded part, not the unbolded part, and about the term "suspected."

Did you understand why I bolded that text in the quote?

Then again, is the T/R loss of thrust, or effectiveness,
In flight?
In transition?
In a hover?

Each case is subtly different ... eh?

A friend died and another had his back AFU by a T/R loss of thrust, with airspeed on the way up toward cruise, and they initially lowered collective as they began to swap ends, and in prep for that final drop and seem to hav echopped the power a bit high over the sea.

So, I ask why someone thinks the FIRST action with suspected T/R problems is cut the engine. I don't get it as a generic response.

I get why in a hover you'd want to do more of a "cut gun" than anything else.

topendtorque, thanks for your explanation.

And with a low inertia head ... ??????

Last edited by Lonewolf_50; 20th Dec 2013 at 21:26.
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Old 20th Dec 2013, 23:07
  #1397 (permalink)  
 
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Hi Anfi and all

On the Sea King, it having had various sorts of TR failures both control and drive over the years, we practised to the nth degree all the combinations. One thing I'm taking from all of that practice (literally hundreds of rehearsals of every possible failure at 6-month intervals over the course of about 20 years that we had the 6-axis sim) and all of the discussion here is that it never prepared me for double engine failure with zero warning when I was doing something else altogether eg in the hold on a procedural rating. So I have no experience of the problem of total power loss getting the Nr down below critical, taught as a specific exercise rather than finding ourselves in the sim-calculated coffin corner. But I do know that we were NEVER taught to chop power as an early action for a TR failure other than in the specific case of drive failure in the low hover, and we did that one as a specific so often that we knew it as a unique condition.

I find it difficult to believe that any pilot regards removal of power as a valid generic solution to tail rotor problems, and further that any organisation would suggest it to be so.
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Old 21st Dec 2013, 00:37
  #1398 (permalink)  
 
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762: And which sim was that (Rn or RAF). I can assure you that once a tail rotor DRIVE failure is presumed - then the engines are chopped in a Sea King (unless you go for range). However in a Tail rotor CONTROL failure situation the engines are NOT chopped. Is that what you meant?
In other helos, especially those with large side tail surfaces like the fan in fin, fenestron types and even the Twin Star, there are other options rather than chopping the engine(s) during a total tail rotor failure.
Secondly one has to be in a position to continue flying after a tail rotor failure, if the tail rotor has gone walkabout from the a/c and the C of G goes out of limits rendering the a/c unflyable
But we digress from this thread - apologies.
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Old 21st Dec 2013, 01:30
  #1399 (permalink)  
 
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Originally Posted by Thomas coupling View Post
I can assure you that once a tail rotor DRIVE failure is presumed - then the engines are chopped in a Sea King .................................................. However in a Tail rotor CONTROL failure situation the engines are NOT chopped. Is that what you meant?
No not control failure, loss of t/r thrust as in drive failure (in the cruise).

TC Don't you just put the lever down to reduce the torque? - lot's of bad accidents (like the Brazillian one) where the engines are chopped and the RRPM are allowed to collapse - lot's of references on this thread from people about shutting off engines - just lower the lever - unless you deliberately want collapsing RRPM for some odd reason - play with the engines later if you want to. Incidentally will a Sea King sustain controlled level flight without t/r? I remember reference to the yaw stability of the S92 not allowing for this and possibly swapping ends


Sven SixTwo said "But I do know that we were NEVER taught to chop power as an early action for a TR failure" - lever down, right?
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Old 23rd Dec 2013, 09:36
  #1400 (permalink)  
 
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Police helicopter crashes onto Glasgow pub

As a fixed wing jockey I have noticed a wide difference of opinion from the rotor heads here as to what might be regarded as essential actions in the event of various TR failure scenarios. While there is no evidence of TR failure in this incident (yet) the disparate views in themselves are interesting and raise an important issue. As there is evidence to suggest that DT only had a few seconds to respond to the emergency which occurred during a critical phase (approach for landing) it was an instinctive response to the perceived circumstances that would dictate the outcome, in so far as he was able to exert any control. If, as a representative sample, you cannot agree the appropriate response to a hypothetical problem such as TR failure ( which can occur in varying modes ) is it not possible that any pilot in an emergency may incorrectly diagnose the wrong failure and apply an in appropriate solution? In this case, evidence is still very sparse but, as yet nothing that confirms mechanical failure.
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