Police helicopter crashes onto Glasgow pub
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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...
and anyway most suspected tailrotor failures aren't real failures anyway...
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.
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http://www.eurocopter.com/site/docs_...18-Rev0-EN.pdf
http://www.eurocopter.com/site/docs_...19-REV0-EN.pdf
Does this advance our understanding at all?
It certainly doesn't indicate Aerospatiale are fixated on tail rotor (sic) failures.
http://www.eurocopter.com/site/docs_...19-REV0-EN.pdf
Does this advance our understanding at all?
It certainly doesn't indicate Aerospatiale are fixated on tail rotor (sic) failures.
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.
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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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.
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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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.
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.
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 ... ??????
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 20:26.
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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.
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.
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.
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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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?
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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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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I'd like to just remind you all that there is no evidence that G-SPAO was preparing to land.
They were just under two miles from base. Over the city Centre. There has been no official release of what the crew were doing there, but to suggest that they were landing is clearly not right.
They were just under two miles from base. Over the city Centre. There has been no official release of what the crew were doing there, but to suggest that they were landing is clearly not right.
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Police helicopter crashes onto Glasgow pub
Fair point. I thought that earlier reports suggested that they had called Glasgow ATC and reported that they were returning to base at Clyde heliport. Has it been confirmed that they were on task in the vicinity of the crash site?
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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.
Helicopter simulators are very much reliant on the programmed parameters. Some things experienced in the simulator (which cannot be practiced for real in the aircraft) will be mainly a software programmer's best guess of what might happen.
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airpolice
I'd like to just remind you all that there is no evidence that G-SPAO was preparing to land.
They were just under two miles from base. Over the city Centre. There has been no official release of what the crew were doing there, but to suggest that they were landing is clearly not right.
I'd like to just remind you all that there is no evidence that G-SPAO was preparing to land.
They were just under two miles from base. Over the city Centre. There has been no official release of what the crew were doing there, but to suggest that they were landing is clearly not right.
At 2218 hrs, the pilot requested clearance from ATC to re-enter the Glasgow Control Zone and return to GCH; this was approved
I think that based on that call, the probability was that they were indeed preparing to land!
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Going back to the SECC in an EC135 along the river from the east (and I have, many many many times over the last few years) I'd still be at 120kts+ at that point.
Going back to the SECC in an EC135 along the river from the east (and I have, many many many times over the last few years) I'd still be at 120kts+ at that point.
Of course, we don't know if they were responding to a quick job on the way in, police radio logs should clear that one up, as would the GPS/radar trace.