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Chinook - Still Hitting Back 3 (Merged)

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Chinook - Still Hitting Back 3 (Merged)

Old 12th Mar 2011, 12:21
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tucumseh & Brian Dixon,

Thank you both for your substantial and illuminating replies.

I hope that the Enquiry, whatever documentation they are able to peruse, will be able to conclusively come to the conclusion that the 'official' outcome of the RAFs proceedings is fatally flawed, having been 'interfered' with by self-important senior officers. The consequences of that should, hopefully, result in overturning the original verdict in this accident.

Such a result will, no doubt, be welcomed by family, friends and colleagues of the Chinook crew. I also feel that there are many who would hope that a result for justice would eventually lead to more - those senior officers having to account for their dishonest actions.
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Old 12th Mar 2011, 12:47
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Well said, Abbey Road.
I watched Sir John Day give his evidence to the HOL on the BBC Parliament Channel. By attempting to pass off the Boeing Simulation as hard fact rather than the "possible" simulation it was, he showed himself to be a complete idiot or a teller of untruths.
I hope the current HOL ask him to explain himself.
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Old 13th Mar 2011, 09:56
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Don't forget, Dalek, that he also tried to 'sell' the SuperTans as a black box. When recalled before the Select Committee, he said that he used that term because the box was coloured black.

It was enjoyable watching him wriggle out of that one though.

Regards, all.
Brian

"Justice has no expiry date" - John Cook
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Old 13th Mar 2011, 10:20
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"he used that term because the box was coloured black." - for heaven's sake - what a fool! It makes you wonder how he 'rose to the rank' - a classic 'Peter' principle?
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Old 13th Mar 2011, 11:12
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BOAC

He may be a fool but he was being a very clever fool because his weasel words and dissembling drew attention away from the inconvenient facts that;


1. According to the AAIB the SuperTANS (display) was switched off, yet MoD's case revolves around it being on until impact and not adversely affecting, or being affected by, other systems (which it was known to).

2. Inexplicably, the SuperTANS manufacturer was allowed to write its own unverified report, whereas the GPS report was written by the AAIB.

3. The two (SuperTANS and Trimble 8000 GPS) were not considered as a "system of systems" at any time and the conflicts between the reports not reconciled by an independent party. Notably, the majority of the SuperTANS report was withheld; perhaps it was a coincidence that this part contains the data which reveals the conflicts.

4. The data extracted from the SuperTANS (by unvalidated and unverified means) was presented by MoD as absolute proof the entire Nav System was both serviceable and accurate. In making this claim, they conveniently ignored the fact none of the Nav System was cleared for use.

5. The GPS had multiple faults, including Time of Day (something quite important in a GPS) and in the power supply (quite important in any avionics).



That is, MoD based their case on a system they had admitted they had no confidence in and had not released to service.

I think the Americans call it "fruit of the poisonous tree". Because the system was deemed unfit for service use at the time, then any evidence relating to it is tainted. Rather like Day in fact.
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Old 13th Mar 2011, 11:20
  #7586 (permalink)  
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He may be a fool but he was being a very clever fool
- agreed, but I was only looking at his understanding of the term 'black box' ie "my wife puts my in-flight sarnies in a black plastic box, therefore it must be part of the avionics equipment". I suspect that to give him credit for deliberately using the term to 'mislead' is allocating undue credit?

I had not come across this little gem before.
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Old 13th Mar 2011, 11:47
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I do remember that Brian. Of course without relying on the information from the TANS computer there could be no Boeing simulation.
I also remember Sir John producing a diagram of the exact cloud formation over the Mull that day. He had it extending over the sea. This was in complete disregard of the evidence of the only witness "at sea" that day, Mr Holbrook.
Yet another work of fiction, presented as fact.
If I did that to a military enquiry, I would expect a long holiday in Colchester.
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Old 13th Mar 2011, 13:23
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If I did that to a military enquiry, I would expect a long holiday in Colchester.
Indeed. It is a wonder there have been no prosecutions. The Air Force Act 1955 is very clear, especially Part 2 29A (Neglect of Duty), 50 (Inaccurate Certification) and 62 (Making of False Documents).


Read the regulations. Read the Release to Service. A slam dunk, as they say.


No wonder MoD tried to claim there was no such thing as an RTS for the Mk2. Pity another part of MoD had already supplied it under FoI, naming the officer who signed it.


That attempted deception is also an offence.
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Old 13th Mar 2011, 14:50
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If I did that to a military enquiry, I would expect a long holiday in Colchester.
Indeed. It is a wonder there have been no prosecutions. ..........

........ That attempted deception is also an offence.
Which is why, although the main thrust of the campaign has been to clear the names of the crew (and rightly so), any momentum should also be used to see that those responsible for the obfuscation and downright untruths should face legal proceedings. It is time for the discomfort to be heaped upon those who believe that they are untouchable, as well as those who support and attempt to lay smoke screens on behalf of the 'untouchables' (where is John Purdey anyway?).
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Old 13th Mar 2011, 17:42
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Yes John Purdey.
Any comments about the deliberate lies of your fellow Air Officer?
Or do accept he is a simple idiot?
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Old 14th Mar 2011, 21:13
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Dalek, I too, remember the dramatic slide presentation given by AVM Day. However, the argument over cloud cover was discredited by the questions from Lord Hooson. Copy of the exchange between Lord H and AVM Day is copied below:

294. But of course your hypothesis necessarily assumes that the cloud was not only over the Mull but was over the sea to some degree, does it not?

A. No. I do not know how far the cloud stretched out over the sea, and it is not part of my analysis—Sorry, I have tried to use fact. Where we have talked about hypothesis is where you have asked me questions. I do not know how far the cloud extended out to sea. There is quite good evidence—I think Mr Holbrook's evidence on that part is quite good in that he says he saw the sun glinting off the window. So I do not have any difficulty with the notion that out to sea there is broken cloud, et cetera, or maybe no cloud, bearing in mind this was a south, 170 wind, over the sea, and the forecast and all the Met conditions were forecasting that as it hit the rising ground that is where the cloud was going to form. It would have formed a little bit off the coast but I have no idea how far off.

295. So you do not know when they changed the way point whether they were in cloud or not?

A. I think that is not true. I do not know for sure whether they were in cloud or not, but they certainly did not have the kind of visibility that they needed to continue a flight over the Mull.

296. I follow that.


So, with absolutely no doubt whatsoever, AVM Day doesn't know whether ZD576 was in cloud or not.

Awkward.....

Regards,
Brian

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Old 14th Mar 2011, 22:09
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Quite strange that he has no idea what so ever as to if they were in cloud or not, has no idea as to how far the cloud extended from the land mass but has no doubt that they we below their weather minima to continue

No wonder one or two regulars in here have decided to stay away as this is simply un feckin believeable
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Old 15th Mar 2011, 07:57
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Change of Waypoint

It is a while since I have used a TANS so my terminology may be incorrect.
A manual change of Waypoint requires a minimum of three(?) buttons to be pushed deliberately.
STR - 3 - ENT?
Less than one minute later the aircraft impacted with the TANS switched off.
The manual Waypoint change would have pointless if the switch off had been earlier. The internal workings of the computer may still have been working, but why push buttons while looking at a blank screen?
A TANS is designed not to be switched off by accident. So why did the crew choose to switch off the primary Navaid and continue towards the Mull at high speed?
And if the RACAL analysis can be used to reconstruct the final moments of flight. Why was the "off" selection never mentioned.
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Old 15th Mar 2011, 09:33
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Direct lift from the AAIB Report in relation to the SuperTANS:
The unit was recovered from the cockpit wreckage area slightly fire scorched but with little apparent impact damage (Fig 16.1). The ON/OFF switch was found at OFF, and an absence of substantial damage to the lift-toggle type switch, including its ramp mechanism, together with ground fire sooting patterns suggested that this had been the setting at impact. However, subsequent examination and memory read-out by the manufacturer, Racal Avionics Ltd, reportedly clearly showed that unit had been operating until impact and it appeared that the switch position had in fact been altered by the effects of the crash. The detailed investigation of the unit was covered in a Racal Report.

Direct lift from RACAL's Report:
1.1.4. SuperTANS serial no. 131 was installed in the Chinook, and was in use at the time of the accident. The memory within the SuperTANS is battery backed, and the content of the memory has been extracted for analysis to provide as much information as possible to assist with the investigation.

1.1.5. The data extracted is that pertaining to the time of last powerdown of the system. The equipment is not designed to provide 'historic' data, but attention has been paid to analysis of data items which may indicate the situation at a time earlier in the flight.

1.1.6. The analysis of the data reveals that the SuperTANS, and the navigation sensors to which it interfaces appear to have been performing perfectly at the time of loss of power. The accuracy of the Doppler position also indicates that all had worked equally as well throughout the flight. The pilot had performed the correct installation procedures, and was making use of the navigation facilities.


So, the AAIB state that, from the evidence presented to them, they believe the SuperTANS to have been switched off yet the manufacturer state that not only was it on, but that it was giving the appearance of working perfectly.

No-one can say at what point in the flight the waypoint change was made, and I would suggest that it is just as difficult to say where the powerdown took place. Was it at the point of impact, or somwhere earlier in that leg? There is a 330m difference between the position of the GPS and Doppler at powerdown. Something?, or nothing?

One thing we can all be absolutely certain of though, and I am grateful to AVM Day for this, is that we know, with absolutely no doubt whatsoever, that the box was coloured black.

Regards all.
Brian

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Old 15th Mar 2011, 10:03
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The question has been asked before - If the toggle switch is OFF, does the RNS252 continue to process data in the background (i.e. "OFF" is a "stand-by" mode)? From answers received, it merely switches off the display.


Switching it "OFF" was a recognised method of solving EMC problems, of which there were many in this immature aircraft.


The person who wrote "appears to be working perfectly" clearly did not read the Trimble 8000 GPS report, which listed both faults and defects in that system.


And MoD completely ignored the fact the systems were not cleared for use.


Simply highlights what was said earlier. There are contradictions in the reports, which MoD did not seek to reconcile because to do so would draw attention to their dissembling.
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Old 15th Mar 2011, 10:17
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There is a 330m difference between the position of the GPS and Doppler at powerdown. Something?, or nothing?
This is something that has nagged at me. As I understand it the TANS works as follows:

1. GPS produces position A;
2. Doppler produces position B;
3. TANS 'blends' A and B, using an algorithm with a weighting to A to arrive at C;
4. TANS displays C to the crew; but
5. The aircraft is almost certainly at D, because the algorithm at 3 is only an approximation of the relationship between A & B.

The fact that the final position data does not reflect the point of impact means that all the other position data is out by some factor of 330m (and this 'could' be greater than 1).

Further without knowlegde of the algorithm it may be that the error factor does not stay constant, particularly if other factors affect the weighting.

At the very least this merits further examination.

EG
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Old 15th Mar 2011, 11:45
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ExGrunt:

If that algorithm is weighted to A then the difference between A and B is almost certainly significantly greater than 330m. I'm far from an expert here, (hush in the cheap seats), but the Doppler gets easily befuddled over water because the surface itself isn't static. When flying over large expanses of water the TANS, (as it was when I operated it on Pumas), was supposed to be manually given information on the surface current and speed and the wind speed and direction so that it could adjust it's Doppler calculations appropriately. I know that after some 3.5 hours over the Caribbean without the benefit of Decca to assist with nav. our TANS was around 10 miles off since we hadn't entered current and wind information because we didn't know for sure what either were.

I'd say that with the accuracy of GPS and the trip over the water a difference of a quarter of a mile wouldn't be inconceivable and the TANS would have required a FIX - CLR - ENTER to reset the Doppler fix to the GPS fix but only when over a known geographic location - something I don't believe the crew had the luxury of passing directly over.
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Old 15th Mar 2011, 13:00
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The problem here is we are all making educated guesses. I don't think there is anyone posting on this site who knows the exact logic of the feeds to the TANS on this particular aircraft.
If the equipment was fully sericeable, statistically:
1. The GPS position would be good to a few metres.
2. The doppler position would be about a mile away.
3. The ADS position would be 1-2 nms in error. (Assuming forecast W/V had been fed in.)
Operating the TANS in either reversionary mode is preferable to swiching it off, because the Computer takes all TAS and Heading variations into consideration. Something Heading Airspeed Timing does not.

If the crew were having problems with the TANS, the first port of call would be SELECT DOPPLER (or ADS with W/V update)

Switching off would be a last resort. Yet the crew (apparently), switched of a fully functioning TANS while approaching a cloud covered headland at high speed.

Does anyone on my planet think that is a logical explanation of events?
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Old 15th Mar 2011, 13:10
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If the crew were having problems with the TANS, the first port of call would be SELECT DOPPLER
Would it? On a system with GPS available and knowing that the system is trying to "average" the GPS position and the Doppler position in a situation where Doppler will always be more of a guess because of surface motion of the water? Did the SuperTANS not have the ability to select GPS only? It would seem to me to be a logical option.
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Old 15th Mar 2011, 13:16
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@dalek:
The problem here is we are all making educated guesses. I don't think there is anyone posting on this site who knows the exact logic of the feeds to the TANS on this particular aircraft.
Agreed, which is why my view is that it needs further investigation.

@AA:
If that algorithm is weighted to A then the difference between A and B is almost certainly significantly greater than 330m.
'If' I am correct then the 330m is the difference between C and D. With your information, as a flight continues A and B diverge. C will lie between A and B, but closer to A. D will be within the GPS error of A but not necessarily between A and B. As A and B diverge C will get further away from A and may get further away from D.

EG
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