Chinook - Still Hitting Back 3 (Merged)
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Hi Brian Dixon.
Simplistic is the right word for your last comment. And I am not sure why the precise evidence of the 'lone'yachtsman' is thought be be so very important. I mean, is anyone suggesting that the aircraft was not at very low level, and at (lets say) highish speed heading directly for cloud covered hills?
THAT was the negligence, and it does not matter exactly when the crew embarked on that profile; the fact is that they did so (unless of course you accept the opinion expressed by some contributors to this very long thread that at some point after waypoint change all the controls locked and flew the aircraft and the helpless crew into granite, incidentally leaving absolutely no trace of technical failure, but leaving evidence that there was a last second attempt to pull up, ie someone was after all in control at that point). JP
Simplistic is the right word for your last comment. And I am not sure why the precise evidence of the 'lone'yachtsman' is thought be be so very important. I mean, is anyone suggesting that the aircraft was not at very low level, and at (lets say) highish speed heading directly for cloud covered hills?
THAT was the negligence, and it does not matter exactly when the crew embarked on that profile; the fact is that they did so (unless of course you accept the opinion expressed by some contributors to this very long thread that at some point after waypoint change all the controls locked and flew the aircraft and the helpless crew into granite, incidentally leaving absolutely no trace of technical failure, but leaving evidence that there was a last second attempt to pull up, ie someone was after all in control at that point). JP
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Hi Mr Purdey,
The evidence of the 'lone' yachtsman should be given the credit it deserves. Mr Holbrook was a witness - the last known eye witness, and his evidence should be given equal merit as afforded to those whose evidence fits the profile best preferred by the MoD. We weren't there. He was, so I for one, don't feel it my place to tell him what he did, or didn't see.
Mr Holbrook's evidence stated that the aircraft was low (as agreed by you), and slow enough for him to believe it to be on a search & rescue mission. So that last bit doesn't fit in with the MoD's belief of 'highish' speed and is therefore either rubbished or conveniently ignored.
I neither know, nor care, whether the controls locked in the last few minutes. They may have done. Equally the crew (all four of them), may have been negligent. However, without the absolute proof required, the verdict is unsustainable - and it is this final point that I have bored everyone rigid with, for the past twelve years.
No-one knows what took place on that flight. We know the beginning, we know the end, but as to what occurred prior to that tragic ending no-one is in any position at all to state with enough evidence to satisfy the burden of proof.
My best, as always.
Brian
"Justice has no expiry date" - John Cook
The evidence of the 'lone' yachtsman should be given the credit it deserves. Mr Holbrook was a witness - the last known eye witness, and his evidence should be given equal merit as afforded to those whose evidence fits the profile best preferred by the MoD. We weren't there. He was, so I for one, don't feel it my place to tell him what he did, or didn't see.
Mr Holbrook's evidence stated that the aircraft was low (as agreed by you), and slow enough for him to believe it to be on a search & rescue mission. So that last bit doesn't fit in with the MoD's belief of 'highish' speed and is therefore either rubbished or conveniently ignored.
I neither know, nor care, whether the controls locked in the last few minutes. They may have done. Equally the crew (all four of them), may have been negligent. However, without the absolute proof required, the verdict is unsustainable - and it is this final point that I have bored everyone rigid with, for the past twelve years.
No-one knows what took place on that flight. We know the beginning, we know the end, but as to what occurred prior to that tragic ending no-one is in any position at all to state with enough evidence to satisfy the burden of proof.
My best, as always.
Brian
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Brian,
I have no wish to denigrate Mr Holbrook as he has been asked to describe a relatively fleeting moment many years ago. How fleeting may be judged by the evidence he gave to both the BOI and the HOL Committee where he indicated that that his sighting of the aircraft was limited to to a 5 second view; he also assessed the speed of the aircraft as "somewhat faster than Sea Kings in level flight". According to MOD that would be an airspeed in of in excess of "100-110 knots".
In his evidence to the FAI however, he indicated that he watched the helicopter for some 25-30 seconds whilst manoeuvering his yacht around fishing boats and that the aircrafts speed was "60 -80 kts." We know, however, that the average groundspeed of the aircraft from the ATC fix to impact was 158 kts. A significant difference.
In my view the failure to obtain evidence from the only other witness is unforgivable.
I have no wish to denigrate Mr Holbrook as he has been asked to describe a relatively fleeting moment many years ago. How fleeting may be judged by the evidence he gave to both the BOI and the HOL Committee where he indicated that that his sighting of the aircraft was limited to to a 5 second view; he also assessed the speed of the aircraft as "somewhat faster than Sea Kings in level flight". According to MOD that would be an airspeed in of in excess of "100-110 knots".
In his evidence to the FAI however, he indicated that he watched the helicopter for some 25-30 seconds whilst manoeuvering his yacht around fishing boats and that the aircrafts speed was "60 -80 kts." We know, however, that the average groundspeed of the aircraft from the ATC fix to impact was 158 kts. A significant difference.
In my view the failure to obtain evidence from the only other witness is unforgivable.
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Cazatou,
I'm happy to agree with you, but surely that means that the failure (for whatever reason) to interview two vital witnesses means that the fullest picture is not known.
Therefore there is, perhaps, an element of doubt as to what happened.
Again, please don't think I am being disrespectful to those on the Board. Nor am I trying to twist your words to suit my purpose. I just see it as a straight forward omission of vital information.
My best, as always.
Brian
"Justice has no expiry date" - John Cook
I'm happy to agree with you, but surely that means that the failure (for whatever reason) to interview two vital witnesses means that the fullest picture is not known.
Therefore there is, perhaps, an element of doubt as to what happened.
Again, please don't think I am being disrespectful to those on the Board. Nor am I trying to twist your words to suit my purpose. I just see it as a straight forward omission of vital information.
My best, as always.
Brian
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Brian
Unfortunately there is no way that it is possible, at this distance in time, to put a specific geographic location on the exact point where it became negligent for the crew of the Chinook to continue at low level on their pre-planned route instead of climbing to Safety Altitude. The only qualified Met Observer in the vicinity was the Lighthouse Keeper and he passed his observations to the BOI.
What is not in doubt is that the poor weather conditions were forecast and the crew should have been prepared for the probability of IMC conditions in the vicinity of the Mull.
Unfortunately there is no way that it is possible, at this distance in time, to put a specific geographic location on the exact point where it became negligent for the crew of the Chinook to continue at low level on their pre-planned route instead of climbing to Safety Altitude. The only qualified Met Observer in the vicinity was the Lighthouse Keeper and he passed his observations to the BOI.
What is not in doubt is that the poor weather conditions were forecast and the crew should have been prepared for the probability of IMC conditions in the vicinity of the Mull.
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But what is in doubt is how far out from the Mull the cloud cover extended, and how far down the Mull the could cover went. Every time the MoD provide a visual representation (including Air Marshal Day in his slide show to the HoL Select Committee), the cloud is always presented as extending quite some way from the landmass. I fear that this is both misleading and unfair as there is no evidence that this was ever the case.
Those witnesses in the cloud/mist/fog were in no position to answer the above question. The only people who could accurately answer that point were lost in the accident.
It would appear that Mr Holbrook's observation (from the same direction as the Chinook - albeit at sea level), states that he could make out the white surrounding wall of the lighthouse. Why is that observation often dismissed whilst that of those in the cloud quoted time and time again?
Kind regards,
Brian
"Justice has no expiry date" - John Cook
Those witnesses in the cloud/mist/fog were in no position to answer the above question. The only people who could accurately answer that point were lost in the accident.
It would appear that Mr Holbrook's observation (from the same direction as the Chinook - albeit at sea level), states that he could make out the white surrounding wall of the lighthouse. Why is that observation often dismissed whilst that of those in the cloud quoted time and time again?
Kind regards,
Brian
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JP, Cazatou
Yes, it is true that at least one of the Air Marshals told the HoL Select Committee that negligence had already occured before the waypoint change. However, so far as I can recall (and I am willing to be corrected), that was the first occasion such a statement had been made in any "public" forum, including the original review comments on the BoI.
It seems to me that a prerequisite for alleging negligence is to be able to state what was done (or omitted) that may have been negligent, and also to identify either the time or the place (or both) where this act or omission occured. The importance is that it is necessary to understand what were the exact circumstances pertaining at the time, which would influence one's view as to whether an action was truly negligent, rather than an error of judgement, or indeed whether it was excusable in the circumstances.
On those grounds, in my opinion, the loose description of "sometime before the waypoint change" is simply not enough to support a finding of negligence, and especially not of negligence to a gross degree.
Regards
Ginseng
It seems to me that a prerequisite for alleging negligence is to be able to state what was done (or omitted) that may have been negligent, and also to identify either the time or the place (or both) where this act or omission occured. The importance is that it is necessary to understand what were the exact circumstances pertaining at the time, which would influence one's view as to whether an action was truly negligent, rather than an error of judgement, or indeed whether it was excusable in the circumstances.
On those grounds, in my opinion, the loose description of "sometime before the waypoint change" is simply not enough to support a finding of negligence, and especially not of negligence to a gross degree.
Regards
Ginseng
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Cazatou
Perhaps you have forgotten a previous conversation between us on page 97:
Your quotation regarding Mr Holbrook's assessment of speed is highly selective, and incomplete.
But I told you that already on page 97.
Have you got it yet????
The reason that it is problematic to prove negligence BEFORE waypoint change is this:
NO RECORDED EVIDENCE WHATEVER, EXISTS AT ANY MOMENT IN THE MINUTES OR SECONDS PRIOR TO WAYPOINT CHANGE
Perhaps you have forgotten a previous conversation between us on page 97:
Tandemrotor
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Oh dear
As FJJP so rightly states, we have, of course been round this particular block before. You do however raise an intesesting point, that I at least had not previously noted.
There is indeed a paragraph in the BOI which states:
Quote:
"The aircraft was sighted by a yachtsman approximately 2-3 nm from the Mull of Kintyre, flying at high speed in a level attitude towards the Mull."
This can only have come from a question, and response, in his evidence to the BOI, which was:
Quote:
Q2. How does the height and speed of the helicopter you saw on 2 Jun 94 compare with the Sea Kings you have seen in the past?
A2. I have seen Sea Kings in 2 attitudes firstly in level flight and secondly in the hover, I would comment that in terms of speed the aircraft I saw on 2 Jun 94 was somewhat faster than Sea Kings in level flight and at a height higher than Sea Kings when they are hovering but comparable with Sea Kings in level flight.
No other information regarding aircraft speed was either sought by the BOI, nor given by the yachtsman!
You will of course note that while the term "high speed" in the BOI is attributed to the yachtsmans evidence, no such term is present in that evidence!
We now turn to his evidence at the FAI when, standing in the dock, he stated:
Quote:
"Again, with the proviso that I only saw this aircraft for a few seconds and I am not an expert in these matters but I would have estimated it's speed to be something between 60 and 80 knots if I had to put a figure on it.
Cross examined: "I take it you accept that that is just, as you have said very fairly, your estimate of it?" -
"Sure, but it was not moving any more rapidly......This is the first time I had seen a twin-rotor blade helicopter and it wasn't moving at an undue speed relative to a Sea King which would have been engaged in looking at the sea surface for example."
Later in his evidence he states:
Quote:
Cross examined "Your estimate of the speed of this helicopter, how was that done?"
"I was asked how was that done? Probably the only reference I have to that is helicopter activity off Troon. The movement from moving to being stationary.
Cross examined "So you had seen other helicopters flying around?"
"I know what 30 knots looks like in a boat so I would have been able to multiply that up and that is it. That is the limit of my understanding of speed.
Cross examined: "So you think it might have been between two or three times faster".....? -
"Yes, it was not going at a helluva speed. It wasn't moving at a speed that would have caused me to remark on it in any way (at) all in terms of moving very rapidly from A to B and that is what caused me to think maybe it was looking, that there was some sort of event and it was looking for somebody."
So cazatou, and in summary, you will see:
1) Nothing in the yachtsman's evidence to the FAI either contradicted, or even "amended" (correct error in, make minor alteration in) his original evidence to the BOI. He simply had more opportunity to clarify.
2) The BOI's only question regarding aircraft speed, was too limited to illicit the accurate information that may otherwise have been available. And there was no follow up question. It was a 'bad' question.
3) It would appear the BOI were incorrect to cite the yachtsman's testimony, as evidence of the aircraft's 'high speed'. He simply NEVER said that!
As you will know, and now it has been demonstrated he was a reliable witness, he also had some very interesting things to say about the weather.
Would you like to debate that next?
BTW
Could you please point me in the direction of the testimony that leads you to suggest he does "not now consider the speed to be as high as he had previously stated and that he had amended his viewpoint after watching RN Sea Kings approach to land at Prestwick."
I can't seem to find it.
Last edited by Tandemrotor : 15th March 2006 at 00:30.
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Oh dear
As FJJP so rightly states, we have, of course been round this particular block before. You do however raise an intesesting point, that I at least had not previously noted.
There is indeed a paragraph in the BOI which states:
Quote:
"The aircraft was sighted by a yachtsman approximately 2-3 nm from the Mull of Kintyre, flying at high speed in a level attitude towards the Mull."
This can only have come from a question, and response, in his evidence to the BOI, which was:
Quote:
Q2. How does the height and speed of the helicopter you saw on 2 Jun 94 compare with the Sea Kings you have seen in the past?
A2. I have seen Sea Kings in 2 attitudes firstly in level flight and secondly in the hover, I would comment that in terms of speed the aircraft I saw on 2 Jun 94 was somewhat faster than Sea Kings in level flight and at a height higher than Sea Kings when they are hovering but comparable with Sea Kings in level flight.
No other information regarding aircraft speed was either sought by the BOI, nor given by the yachtsman!
You will of course note that while the term "high speed" in the BOI is attributed to the yachtsmans evidence, no such term is present in that evidence!
We now turn to his evidence at the FAI when, standing in the dock, he stated:
Quote:
"Again, with the proviso that I only saw this aircraft for a few seconds and I am not an expert in these matters but I would have estimated it's speed to be something between 60 and 80 knots if I had to put a figure on it.
Cross examined: "I take it you accept that that is just, as you have said very fairly, your estimate of it?" -
"Sure, but it was not moving any more rapidly......This is the first time I had seen a twin-rotor blade helicopter and it wasn't moving at an undue speed relative to a Sea King which would have been engaged in looking at the sea surface for example."
Later in his evidence he states:
Quote:
Cross examined "Your estimate of the speed of this helicopter, how was that done?"
"I was asked how was that done? Probably the only reference I have to that is helicopter activity off Troon. The movement from moving to being stationary.
Cross examined "So you had seen other helicopters flying around?"
"I know what 30 knots looks like in a boat so I would have been able to multiply that up and that is it. That is the limit of my understanding of speed.
Cross examined: "So you think it might have been between two or three times faster".....? -
"Yes, it was not going at a helluva speed. It wasn't moving at a speed that would have caused me to remark on it in any way (at) all in terms of moving very rapidly from A to B and that is what caused me to think maybe it was looking, that there was some sort of event and it was looking for somebody."
So cazatou, and in summary, you will see:
1) Nothing in the yachtsman's evidence to the FAI either contradicted, or even "amended" (correct error in, make minor alteration in) his original evidence to the BOI. He simply had more opportunity to clarify.
2) The BOI's only question regarding aircraft speed, was too limited to illicit the accurate information that may otherwise have been available. And there was no follow up question. It was a 'bad' question.
3) It would appear the BOI were incorrect to cite the yachtsman's testimony, as evidence of the aircraft's 'high speed'. He simply NEVER said that!
As you will know, and now it has been demonstrated he was a reliable witness, he also had some very interesting things to say about the weather.
Would you like to debate that next?
BTW
Could you please point me in the direction of the testimony that leads you to suggest he does "not now consider the speed to be as high as he had previously stated and that he had amended his viewpoint after watching RN Sea Kings approach to land at Prestwick."
I can't seem to find it.
Last edited by Tandemrotor : 15th March 2006 at 00:30.
But I told you that already on page 97.
Have you got it yet????
The reason that it is problematic to prove negligence BEFORE waypoint change is this:
NO RECORDED EVIDENCE WHATEVER, EXISTS AT ANY MOMENT IN THE MINUTES OR SECONDS PRIOR TO WAYPOINT CHANGE
Last edited by Tandemrotor; 29th Jun 2006 at 08:37.
Ginseng,
Bill Wratten said, in his Pilot article defending his decision, that the negligence occurred before waypoint change. I think I am right in saying that this article preceded the Lords Select Committee by some time.
We come again full circle to the crucial point. What was the picture from the cockpit at the point at which they were deemed to be negligent? John Purdey agreed, a long time ago, that if he had been present in the cockpit at waypoint change he would have told the crew they were being negligent. And yet, he continually fails to tell us, when asked, what he would have seen from the cockpit, which would have drawn him to that conclusion.
All we know with any certainty is that at least part of the Mull was obscured by cloud. From Mr Holbrook's account it is also probable that they could at least see the lower slopes of the Mull. Apart from that, we have no idea how much they could see at that time.
John Purdey, once again I ask, if they were going too fast in the conditions, what were the conditions as seen from the cockpit at that point? In other words, what could they see? What could they not see? Unless these questions can be answered with certainty, you cannot say they were negligent, at that point, with absolutely no doubt whatsoever.
Bill Wratten said, in his Pilot article defending his decision, that the negligence occurred before waypoint change. I think I am right in saying that this article preceded the Lords Select Committee by some time.
We come again full circle to the crucial point. What was the picture from the cockpit at the point at which they were deemed to be negligent? John Purdey agreed, a long time ago, that if he had been present in the cockpit at waypoint change he would have told the crew they were being negligent. And yet, he continually fails to tell us, when asked, what he would have seen from the cockpit, which would have drawn him to that conclusion.
All we know with any certainty is that at least part of the Mull was obscured by cloud. From Mr Holbrook's account it is also probable that they could at least see the lower slopes of the Mull. Apart from that, we have no idea how much they could see at that time.
John Purdey, once again I ask, if they were going too fast in the conditions, what were the conditions as seen from the cockpit at that point? In other words, what could they see? What could they not see? Unless these questions can be answered with certainty, you cannot say they were negligent, at that point, with absolutely no doubt whatsoever.
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Allow me to express an opinion.
What Pulse has said is exactly right. I believe that it is impossible to determine what was occurring in, or with ZD576 in the moments leading up to waypoint change.
There is simply NO RECORD.
The best available evidence, from a yachtsman, suggests they were operating in total compliance with the Visual Flight Rules.
I am then, at a loss to understand, how anyone on board that aircraft can be deemed negligent at that time.
I am however aware that, this concept of 'shifting' the moment of negligence to a point prior to waypoint change, was a later development in the position of the two AMs, and MOD. It most definitely was never mentioned at any time during the BOI process, nor I strongly suspect, at the subsequent FAI.
Perhaps the AMs felt that the debate was swinging against them, and they needed to 'tweak' their argument?
I am also aware that this 'shift', though utterly devoid of any factual evidence, is a very useful 'device' for avoiding further inconvenient questions regarding ANY subsequent event affecting ZD576 or it's crew.
If the precise timing of the crew's negligence is so obvious, I ask only this:
1) Why was it not mentioned at any time in the BOI?
2) Why was it never referred to in the subsequent FAI?
I think the answer to those two questions is obvious. Don't you? (see line 8 of this post!)
What Pulse has said is exactly right. I believe that it is impossible to determine what was occurring in, or with ZD576 in the moments leading up to waypoint change.
There is simply NO RECORD.
The best available evidence, from a yachtsman, suggests they were operating in total compliance with the Visual Flight Rules.
I am then, at a loss to understand, how anyone on board that aircraft can be deemed negligent at that time.
I am however aware that, this concept of 'shifting' the moment of negligence to a point prior to waypoint change, was a later development in the position of the two AMs, and MOD. It most definitely was never mentioned at any time during the BOI process, nor I strongly suspect, at the subsequent FAI.
Perhaps the AMs felt that the debate was swinging against them, and they needed to 'tweak' their argument?
I am also aware that this 'shift', though utterly devoid of any factual evidence, is a very useful 'device' for avoiding further inconvenient questions regarding ANY subsequent event affecting ZD576 or it's crew.
If the precise timing of the crew's negligence is so obvious, I ask only this:
1) Why was it not mentioned at any time in the BOI?
2) Why was it never referred to in the subsequent FAI?
I think the answer to those two questions is obvious. Don't you? (see line 8 of this post!)
Last edited by Tandemrotor; 29th Jun 2006 at 11:51.
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When the crew selected the waypoint change they would have been approx 600 metres from the coast. The HOL committee accepted that the waypoint change would not have occurred if the Pilots were experiencing significant difficulty in handling the aircraft.
They did not turn but continued to fly towards fog enshrouded high ground at high speed ( AAIB estimated the groundspeed at impact was "of the order of 150 kts" whilst Boeing calculated groundspeed as 162.8 kts at impact. Overall groundspeed from the ATC fix on leaving the Belfast CTZ to impact was 158 kts).
Mr Holbrook could see breakers on the coastline but not the lighthouse structure. All the eyewitnesses on the Mull reported the weather as generally foggy with the lighthouse keeper (a Met observer) estimating visibility as 15 to 20 metres at most.
The pilots failed to observe the rules for VFR flight and crashed at high speed into high ground in poor weather which had been forecast. Even if an unknown and untraceable "catastrophic event"occurred, it would have to have been after waypoint change by which time they had already been deemed to be negligent.
They did not turn but continued to fly towards fog enshrouded high ground at high speed ( AAIB estimated the groundspeed at impact was "of the order of 150 kts" whilst Boeing calculated groundspeed as 162.8 kts at impact. Overall groundspeed from the ATC fix on leaving the Belfast CTZ to impact was 158 kts).
Mr Holbrook could see breakers on the coastline but not the lighthouse structure. All the eyewitnesses on the Mull reported the weather as generally foggy with the lighthouse keeper (a Met observer) estimating visibility as 15 to 20 metres at most.
The pilots failed to observe the rules for VFR flight and crashed at high speed into high ground in poor weather which had been forecast. Even if an unknown and untraceable "catastrophic event"occurred, it would have to have been after waypoint change by which time they had already been deemed to be negligent.
Last edited by cazatou; 29th Jun 2006 at 12:49.
Caz
"When the crew selected the waypoint change they would have been approx 600 metres from the cliffs".
While I try not to comment on aircrew matters, and gladly defer to experts on in that area, can you say what possible effect the acknowledged errors (not to mention defects) in the Nav system may have had on this "approximation"? Waypoint selection was via SuperTANS. In many respects it is just a computer - rubbish in, rubbish out. One source of its data is known to be unreliable over water and another had design defects. In another post someone (correctly I believe) suggested that, given the distance flown over water, this "approx 600m" could be more than double.
I'm too old to have repaired TANS but I have extensive knowledge of repairing source systems, for example various Doppler, GMC and Rad Alt. They are all inherently error prone, and the error build-up is, I believe, one reason why the TANS algorithm is weighted in favour of one source over another. I'm being deliberately simplistic on a quite complex technical matter, but my point is that the "approximation" is just that - no-one knows where the waypoint change took place. Therefore, I think using that approximation as a reference point for determining negligence is very tenuous indeed.
My argument is one that no-one knows if the Nav System was telling the crew their correct position. The subsequent Racal "testing" of the surviving bits of TANS can only have taken place in a benign, wholly unrepresentative environment, devoid of typical external influences such as input errors, EMC and poor bonding. Importantly (in my opinion) it is a known fact that the crew were unhappy about TANS (but what they probably meant was they did not trust the indicated result of calculations based on error-prone external data). The MoD's position is that, based on this unrepresentative testing, the Nav System was both accurate and serviceable. (Two quite different things, each dependant on many external factors which were destroyed with ZD576 or are impossible to replicate).
As ever, I am not suggesting this as the cause, but think it constitutes reasonable doubt. I'm quite willing to be corrected on any of this as I'm not overly familiar with the actual Mk2 nav fit.
"When the crew selected the waypoint change they would have been approx 600 metres from the cliffs".
While I try not to comment on aircrew matters, and gladly defer to experts on in that area, can you say what possible effect the acknowledged errors (not to mention defects) in the Nav system may have had on this "approximation"? Waypoint selection was via SuperTANS. In many respects it is just a computer - rubbish in, rubbish out. One source of its data is known to be unreliable over water and another had design defects. In another post someone (correctly I believe) suggested that, given the distance flown over water, this "approx 600m" could be more than double.
I'm too old to have repaired TANS but I have extensive knowledge of repairing source systems, for example various Doppler, GMC and Rad Alt. They are all inherently error prone, and the error build-up is, I believe, one reason why the TANS algorithm is weighted in favour of one source over another. I'm being deliberately simplistic on a quite complex technical matter, but my point is that the "approximation" is just that - no-one knows where the waypoint change took place. Therefore, I think using that approximation as a reference point for determining negligence is very tenuous indeed.
My argument is one that no-one knows if the Nav System was telling the crew their correct position. The subsequent Racal "testing" of the surviving bits of TANS can only have taken place in a benign, wholly unrepresentative environment, devoid of typical external influences such as input errors, EMC and poor bonding. Importantly (in my opinion) it is a known fact that the crew were unhappy about TANS (but what they probably meant was they did not trust the indicated result of calculations based on error-prone external data). The MoD's position is that, based on this unrepresentative testing, the Nav System was both accurate and serviceable. (Two quite different things, each dependant on many external factors which were destroyed with ZD576 or are impossible to replicate).
As ever, I am not suggesting this as the cause, but think it constitutes reasonable doubt. I'm quite willing to be corrected on any of this as I'm not overly familiar with the actual Mk2 nav fit.
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tucumseh
The point is that the were supposed to be flying VFR with the super Tans to assist their navigation. The waypoint change would have pointed them in the direction of the next waypoint but they never turned and continued towards the lighthouse which was in fog.
The point is that the were supposed to be flying VFR with the super Tans to assist their navigation. The waypoint change would have pointed them in the direction of the next waypoint but they never turned and continued towards the lighthouse which was in fog.
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cazatou (K52)
I have read the contribution of tucumseh, and note that you are forced to rest your allegation of negligence (which requires the highest possible standard of proof) on information recovered from a piece of navigation equipment which was never designed to store historical data!
Don't you think you are clutching at straws?
I have read the contribution of tucumseh, and note that you are forced to rest your allegation of negligence (which requires the highest possible standard of proof) on information recovered from a piece of navigation equipment which was never designed to store historical data!
Don't you think you are clutching at straws?
Last edited by Tandemrotor; 29th Jun 2006 at 12:50.
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cazatou: When the crew selected the waypoint change they would have been approx 600 metres from the cliffs
Page 12 has a chart Figure 6. Vertical flight Path to Last Altitude Update showing terrain and distance based on a closing speed of 158.5 knots. That shows waypoint change at ~ 1,900ft or 600m from landfall at sea level. Based on the possible cruising altitude variations discussed then waypoint change was estimated at between 5,000 and 5,300ft from the 'cliffs' ie 1,500-1,600m.
EG
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Brian
You wrote <<But what is in doubt is how far out from the Mull the cloud cover extended, and how far down the Mull the could cover went. Every time the MoD provide a visual representation (including Air Marshal Day in his slide show to the HoL Select Committee), the cloud is always presented as extending quite some way from the landmass. I fear that this is both misleading and unfair as there is no evidence that this was ever the case.
Those witnesses in the cloud/mist/fog were in no position to answer the above question. The only people who could accurately answer that point were lost in the accident.>>
.
You are quite right to question the (misre) presentation of the cloud cover; while your last sentence is true (“The only people …”), we can assume from what we know that it was typical of that area at that time of day, at that time of year, with that prevailing wind – clear at sea, mist forming just after shoreline as air rises following ground, often clear at a small height above sloping ground so that a/c can be in clear air over ground hugging mist on the lower part of the slope at least. These conditions are very, very common in that part of the world under similar circumstances and there can be no excuse for, say, AVM Day to have misrepresented conditions on those slides - he had to have been selling the simplistic picture that they were flying VFR in IMC conditions – and why the hell have those on this thread who have flown this area at low level not spoken up loudly on this point?
.
On another issue, Cazatou’s point about the second witness is important in regard to how the authorities managed the investigations: I do not believe that the second yottie would have contributed to the judgment of the speed as neither would have been able to give even an approximate guess (large unfamiliar object with nothing nearby to compare with, etc); however, that one of only two witnesses of the final part of the flight was not called is indeed extraordinary – just by way of examples, he could have seen something the other had missed, say a plume of smoke that the other had dismissed as exhaust, a jink, a bit falling off, someone mooning, anything odd – even the local bobbies looking into a bike theft would ask around more diligently – unless they too had a preconceived idea of who was going to get blamed.
.
Now what is it that is so confusing about the nav systems and the sequence of events after all these years?
I’ll put my view as simply as I can (again):
They did not go straight on at waypoint change, they TURNED RIGHT – towards danger.
The SuperTANS of the time was intrinsically unreliable to any degree of accuracy after such a water crossing as the algorithm more heavily weights the Doppler input (in case of complete loss of GPS due to jamming) which is sporadic due to wave velocities and specular reflection and only the combined result was available (unlike in previous TANS as I believe); these pilots were aware of this and cautioned other members of their flight – they would not have trusted it better than ½ a mile – if relying upon it to turn in plenty of time clear of the misty headland and remain well in the clear air they would have turned much sooner rather than later – waypoint A was very close in, remember.
Nevertheless, the experts pronounced that it had been accurate in this case at the crucial time (from analysis of the stored data, etc).
This is very important – it means that at the time of waypoint change, the SuperTANS (in this instance) had been reasonably accurate – so that if they had had a clear visual reference by which they were judging their distance to go to their turn, it should have agreed with the SuperTANS at waypoint A AND THEY SHOULD HAVE STARTED THEIR TURN. This suggests to me that they did not have a clear visual reference at that point. They did have control though and made a steer to the right of a few degrees.
To carry on with their ferry job safely, they only had to turn left a few degrees at that point.
They were flying in clear air until the last few seconds and demonstrated control by starting an appropriate emergency manoeuvre in those circumstances for a large twin rotor to turn, climb, and slew (to lose speed) – the start of this manoeuvre coincided with when they would have seen the shoreline passing beneath them, entering mist, and the RADALT going off all in very quick succession - this suggests to me that they were taken by surprise when these events happened, that they had not realized just how close they had got – they could have seen the Mull for miles but its ground detail was obscured making it difficult to judge their distance visually at that speed.
If they had had a good visual reference, they would have turned AT waypoint A; if they did not have vis conditions and were relying upon the SuperTANS to keep them well clear of the dodgy area, they would have turned well before waypoint A (remember, they would not have trusted the accuracy of the SuperTANS).
The turn to the right is a vital clue – they had to be heading for something specific to make such a change.
There is only one system that helo pilots trust enough that it can overwhelm their visual judgment of range – DME. A system that gives accurate range (UHF DME function) and an azimuth bearing to a portable handset (PRC-112) had just been delivered to the RAF about that time, specially for fitting to the HC2 Chinooks. If they were doing a demo of the new system (some on board would have been very interested), say overflying a guy on the ground at the lighthouse heli pad, he could actually vector the pilot in (the handling pilot’s intercom was set appropriately); there were plenty of PRC-112s on the Mull that day as the American unit there had them issued to a man – how handy!
Provided the man on the ground was where he was supposed to be there wouldn’t have been a problem.
.
If you disagree with the possibility of the use of the PRC-112 system, why not tell us all when exactly it was first used in RAF Chinooks? 12 years on hardly a super sensitive secret defence wise – yet the topic is avoided like a floater in the jacuzzi– smells like there is a connection.
You wrote <<But what is in doubt is how far out from the Mull the cloud cover extended, and how far down the Mull the could cover went. Every time the MoD provide a visual representation (including Air Marshal Day in his slide show to the HoL Select Committee), the cloud is always presented as extending quite some way from the landmass. I fear that this is both misleading and unfair as there is no evidence that this was ever the case.
Those witnesses in the cloud/mist/fog were in no position to answer the above question. The only people who could accurately answer that point were lost in the accident.>>
.
You are quite right to question the (misre) presentation of the cloud cover; while your last sentence is true (“The only people …”), we can assume from what we know that it was typical of that area at that time of day, at that time of year, with that prevailing wind – clear at sea, mist forming just after shoreline as air rises following ground, often clear at a small height above sloping ground so that a/c can be in clear air over ground hugging mist on the lower part of the slope at least. These conditions are very, very common in that part of the world under similar circumstances and there can be no excuse for, say, AVM Day to have misrepresented conditions on those slides - he had to have been selling the simplistic picture that they were flying VFR in IMC conditions – and why the hell have those on this thread who have flown this area at low level not spoken up loudly on this point?
.
On another issue, Cazatou’s point about the second witness is important in regard to how the authorities managed the investigations: I do not believe that the second yottie would have contributed to the judgment of the speed as neither would have been able to give even an approximate guess (large unfamiliar object with nothing nearby to compare with, etc); however, that one of only two witnesses of the final part of the flight was not called is indeed extraordinary – just by way of examples, he could have seen something the other had missed, say a plume of smoke that the other had dismissed as exhaust, a jink, a bit falling off, someone mooning, anything odd – even the local bobbies looking into a bike theft would ask around more diligently – unless they too had a preconceived idea of who was going to get blamed.
.
Now what is it that is so confusing about the nav systems and the sequence of events after all these years?
I’ll put my view as simply as I can (again):
They did not go straight on at waypoint change, they TURNED RIGHT – towards danger.
The SuperTANS of the time was intrinsically unreliable to any degree of accuracy after such a water crossing as the algorithm more heavily weights the Doppler input (in case of complete loss of GPS due to jamming) which is sporadic due to wave velocities and specular reflection and only the combined result was available (unlike in previous TANS as I believe); these pilots were aware of this and cautioned other members of their flight – they would not have trusted it better than ½ a mile – if relying upon it to turn in plenty of time clear of the misty headland and remain well in the clear air they would have turned much sooner rather than later – waypoint A was very close in, remember.
Nevertheless, the experts pronounced that it had been accurate in this case at the crucial time (from analysis of the stored data, etc).
This is very important – it means that at the time of waypoint change, the SuperTANS (in this instance) had been reasonably accurate – so that if they had had a clear visual reference by which they were judging their distance to go to their turn, it should have agreed with the SuperTANS at waypoint A AND THEY SHOULD HAVE STARTED THEIR TURN. This suggests to me that they did not have a clear visual reference at that point. They did have control though and made a steer to the right of a few degrees.
To carry on with their ferry job safely, they only had to turn left a few degrees at that point.
They were flying in clear air until the last few seconds and demonstrated control by starting an appropriate emergency manoeuvre in those circumstances for a large twin rotor to turn, climb, and slew (to lose speed) – the start of this manoeuvre coincided with when they would have seen the shoreline passing beneath them, entering mist, and the RADALT going off all in very quick succession - this suggests to me that they were taken by surprise when these events happened, that they had not realized just how close they had got – they could have seen the Mull for miles but its ground detail was obscured making it difficult to judge their distance visually at that speed.
If they had had a good visual reference, they would have turned AT waypoint A; if they did not have vis conditions and were relying upon the SuperTANS to keep them well clear of the dodgy area, they would have turned well before waypoint A (remember, they would not have trusted the accuracy of the SuperTANS).
The turn to the right is a vital clue – they had to be heading for something specific to make such a change.
There is only one system that helo pilots trust enough that it can overwhelm their visual judgment of range – DME. A system that gives accurate range (UHF DME function) and an azimuth bearing to a portable handset (PRC-112) had just been delivered to the RAF about that time, specially for fitting to the HC2 Chinooks. If they were doing a demo of the new system (some on board would have been very interested), say overflying a guy on the ground at the lighthouse heli pad, he could actually vector the pilot in (the handling pilot’s intercom was set appropriately); there were plenty of PRC-112s on the Mull that day as the American unit there had them issued to a man – how handy!
Provided the man on the ground was where he was supposed to be there wouldn’t have been a problem.
.
If you disagree with the possibility of the use of the PRC-112 system, why not tell us all when exactly it was first used in RAF Chinooks? 12 years on hardly a super sensitive secret defence wise – yet the topic is avoided like a floater in the jacuzzi– smells like there is a connection.
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Tandemrotor,
You are, of course, entitled to your opinion.
Your viewpoint is not shared by MOD or HMG. Can you quote any instance of a fault occurring on a Chinook Mk2 in the last 12 years that would, if it had occurred on ZD576, have caused the accident and disappeared completely without trace?
You are, of course, entitled to your opinion.
Your viewpoint is not shared by MOD or HMG. Can you quote any instance of a fault occurring on a Chinook Mk2 in the last 12 years that would, if it had occurred on ZD576, have caused the accident and disappeared completely without trace?
Caz
“Your viewpoint is not shared by MOD or HMG”.
I’m sorry Caz, but the views of the MoD and HMG are irredeemably tainted. Their willingness to deceive and constant refusal to answer reasonable questions makes me deeply cynical of their motives. I think many share this view but, as ever, you are perfectly entitled to yours.
“Can you quote any instance of a fault occurring on a Chinook Mk2 in the last 12 years that would, if it had occurred on ZD576, have caused the accident and disappeared completely without trace?”
Yes, witnessed personally, but I’m not about to publish it in open forum. (Clearly I cannot state categorically it would have caused an accident, but I can say with absolutely certainty that it was, in my view, sufficiently serious that if I were responsible for the aircraft I would not have allowed it to fly and would have ordered a fleet inspection. There speaks a certified MoD a/c inspector, for what it's worth). The MoD was advised but you would have to ask them what, if anything, they did, as they spoke no further to me (or the other witnesses). The key word is intermittent, and any a/c maintainer will tell you they are the worst type of faults to trace, as they can often be very serious but impossible to replicate. Apprentices learn that on day 1. However, the issue of a fault is less relevant to our case given the MoD’s own admission that the aircraft nav system suffered from design defects – something far more serious.
To refer back to a previous post I made, we should not fall into the trap of accepting the MoD inference that, if (any) aircraft can take off/fly/land it is therefore serviceable and safe. This could not be further from the truth. In the 3 years preceding the accident the MoD (specifically AMSO/AML) went to great lengths to slash the budget which had previously ensured (as far as possible) that the avionic systems were safe/serviceable/at the latest mod state. Over 25% each year. The result was avionic kit fitted to a/c with many mods missing, from both the kit and the aircraft documentation. (This is open source in NAO and SC reports and was referred to on ZD576). Perhaps not Class As (although I can cite attempts to prevent even these safety critical mods being procured), but certainly Class B/C/Ds. The MoD knows this, and they almost certainly know it compromises their position. It is why they will not debate the subject, preferring to give unrelated and even nonsensical answers in the hope we will give up.
“Your viewpoint is not shared by MOD or HMG”.
I’m sorry Caz, but the views of the MoD and HMG are irredeemably tainted. Their willingness to deceive and constant refusal to answer reasonable questions makes me deeply cynical of their motives. I think many share this view but, as ever, you are perfectly entitled to yours.
“Can you quote any instance of a fault occurring on a Chinook Mk2 in the last 12 years that would, if it had occurred on ZD576, have caused the accident and disappeared completely without trace?”
Yes, witnessed personally, but I’m not about to publish it in open forum. (Clearly I cannot state categorically it would have caused an accident, but I can say with absolutely certainty that it was, in my view, sufficiently serious that if I were responsible for the aircraft I would not have allowed it to fly and would have ordered a fleet inspection. There speaks a certified MoD a/c inspector, for what it's worth). The MoD was advised but you would have to ask them what, if anything, they did, as they spoke no further to me (or the other witnesses). The key word is intermittent, and any a/c maintainer will tell you they are the worst type of faults to trace, as they can often be very serious but impossible to replicate. Apprentices learn that on day 1. However, the issue of a fault is less relevant to our case given the MoD’s own admission that the aircraft nav system suffered from design defects – something far more serious.
To refer back to a previous post I made, we should not fall into the trap of accepting the MoD inference that, if (any) aircraft can take off/fly/land it is therefore serviceable and safe. This could not be further from the truth. In the 3 years preceding the accident the MoD (specifically AMSO/AML) went to great lengths to slash the budget which had previously ensured (as far as possible) that the avionic systems were safe/serviceable/at the latest mod state. Over 25% each year. The result was avionic kit fitted to a/c with many mods missing, from both the kit and the aircraft documentation. (This is open source in NAO and SC reports and was referred to on ZD576). Perhaps not Class As (although I can cite attempts to prevent even these safety critical mods being procured), but certainly Class B/C/Ds. The MoD knows this, and they almost certainly know it compromises their position. It is why they will not debate the subject, preferring to give unrelated and even nonsensical answers in the hope we will give up.