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Surtchris
24th Aug 2012, 17:57
I was looking at a Trident cockpit and something occured to me that might or might not explain the awful Papa India crash. I note the droop flap lever has a long travel - looks like twelve inches. If the lever was accidentally knocked off the spring strut, which could easily happen in turbulence because the P2 hand/wrist would be over the lever when selecting a new altitude in the height select autopilot panel, would this lever hydraulically travel back to droop flaps up position or would it stay where it was indicating to the pilots that the flaps were extended when they had retracted.

Aileron Drag
24th Aug 2012, 20:57
I am really lost for words, and don't know how to even begin answering this hypothesis.:\

Ex-Gripper pilots - Help!

Surtchris
24th Aug 2012, 22:01
The purpose of the thread was not to pose a hypothesis but ask a question. Was the lever operated manually with no mechanical override? If the lever for whatever reason was knocked out of position so that the droops retracted was it possible that the droops would appear to be extended when they were in fact retracted.

PAXboy
24th Aug 2012, 22:26
Surtchris You may not be aware but there was an extremely long and detailed thread on this subject in the last two months - given the anniversary. It references the reports and much 1st hand information.

The thread is in this very forum and has 92 posts in it. When you have read the thread, you might want to be the #93 poster.
http://www.pprune.org/aviation-history-nostalgia/488300-g-arpi-trident-tragedy-40-years-ago-today-5.html

I appreciate that you are new to the forum (and welcome!) you may find it helpful to use the Search facility for a topic before starting a new thread.

Surtchris
25th Aug 2012, 07:31
PAXboy Thank you for your help. I am not a regular visitor to PPRuNe. I did actually read recently the full Lane enquiry which should be helpful background information and I will now read the thread as you suggested.

Surtchris
28th Aug 2012, 10:47
PAXboy if you’re around and anybody else who can help. I have now read all 92 posts but I think this thread may have gone off the radar - last post 24th July. I found it very interesting. I used to fly quite a lot on business on Tridents and, I must say, I am glad I hadn’t read this thread when I did. It all sounds a bit sketchy. The Trident, I gather, was quite a handful unless you knew what you were doing and according to information provided on this thread some captains didn’t.

The Papa India crash was the most horrific airline disaster and I still have vivid memories of the subesequent press coverage. I lived in Maidenhead, as I believe did Simon Ticehurst, and we were the same age. I was friends with three Hamble cadets; we used to fly together in a Cherokee 140 from White Waltham. A few anxious hours before I found out none of them were involved as they were all by then first officers. They went onto to become captains and one a fleet captain but presumably they have now retired.

I do realise that this crash has been done and dusted in a previous thread and many would prefer to move on and forget it. I found one post particularly distressing concerning Jeremy Keighley’s mother who said ‘surely my son didn’t kill all those people’. I picked up on something a few years ago which has been nagging at the back of my mind ever since and whilst I know airline professionals, pilots and others, don’t like amateurs commenting on airline business I would appreciate it if somebody could humour me and at least put my mind at rest.

Unfortunately neither the Lane Enquiry nor the threads deal with my specific issue. I can only repeat the Aileron Drag post - Ex Gripper pilots- Help. May I ask Gripper pilots to be kind enough to spend a few minutes of their time to take a trip down memory lane and look at the flight deck of the Trident by visiting http://en.wikipedia.org/wiki/File:TridentFlightDeck.JPG (http://en.wikipedia.org/wiki/File:TridentFlightDeck.JPG). There is a full resolution option which gives a detailed view of the Trident flight deck.

For twenty years I ran my own consultancy company which provided consultancy advice to companies trading in many corporate areas including engineering, management training and quality assurance. I was also involved in couple of aviation projects including working with a company that operated a BAC1-11 from Heathrow in a twenty five seat executive jet configuration. Fun times including a memorable full power take off on a windy day from 27R in a Gulf Stream Four with four of us on board. As the training captain said afterwards, ‘Did we go up!’

I had a reputation on occasions for what some might have perceived as fixating but usually, not always, apologies were in order when folk discovered I was right. I certainly do have a problem with the Papa India disaster, as I didn’t believe at the time and, having read the Lane enquiry recently, I still don’t believe that anybody on the flight deck selected to withdraw the droop flaps shortly after take off, speed 170 knots with the aircraft banked and in heavy turbulence. The Lane enquiry commissioned by Michael Heseltine on 19th June 1972 was a public enquiry presided over by High Court Judge Sir Geoffrey Lane. The enquiry swiftly deteriorated into a Fred Karno show as a result of litigious interests, with lawyers interfering in an unprofessional way with proceedings, and media hype because the enquiry was held in the public arena. One AIB inspector committed suicide probably as a result of the pressures involved and some of the recommendations bordered on the absurd.

All of which brings me back to the Trident cockpit because I am sure that some other factor was involved in this accident that did not surface at The Lane Enquiry. At first sight the droop flap lever, and its position in relation to the auto pilot height select panel, looks like an accident waiting to happen. The problem is that I didn’t operate these levers or sit in the Trident cockpit and only a Trident pilot can check me out on this and verify whether I am making a valid point. The right hand lever operating the trailing edge flaps is fit for purpose because it is an incremental lever with five settings, flaps up, flaps 10%, 15%, 23% and full flaps for landing. The droops lever was housed on the left under the same metal cover and, if this picture of the cockpit gives me a proper perspective, this lever was not fit for purpose because it appears to have to travel the same length as the incremental lever. The droop lever has to be pulled with nothing happening until it reaches the end of its travel and is locked into place over/under the spring strut, which initiates droop flap extension. Conversely when retracting the flaps the lever had to be pulled all the way back to the droop flaps up position, which apart from being a waste of effort, could cause problems if the lever was knocked out of position, as it might appear to the pilots, particularly in turbulence with the plane bumping about, that the droops were extended when they had retracted. As a point of design principle a one function lever, droops up/droops down, like an undercarriage lever shouldn’t have any travel. Looking at the lever arm its width appears to be about half an inch but it is hard to tell. My primary concern is how far back up the travel would this lever have to go before the droops retracted and wouldn’t this leave the lever still looking as if the droops were extended; unless the design guys fitted some sort of spring/hydraulic mechanism which put the lever back to the up position (retracted) if the pilot didn’t push the lever all the way back to its up (retracted) position.

The height select panel is positioned to the left of the droop lever and when the droops are up (retracted) the lever is above the height select panel but when the droops are down (extended) the RHS pilot, who would normally input altitude selection because the height select panel is on the right of the centre console, has to operate over the droop lever to input altitude selections and his hand /wrist are above the lever. Remembering a particularly bumpy approach to Luton on a Ryan Air turbo prop my arms were knocked of the seat rest and it isn’t difficult to imagine the difficulties in turbulence that would be experienced by the RHS pilot to input altitude selections in turbulence while the droops are down (Extended).

Over the years I have spoken to quite a few airline captains about the Papa India disaster and all seem to agree that what happened was that Captain Stanley Key following re clearance by ATC from 1500ft to 6000ft told P2 Jeremy Keighley to put it in and because Keighley was inexperienced he mistook Key’s command to mean retract the droop flaps. This theory was also advanced at the Lane enquiry. Basically this theory doesn’t work because if Keighley had pushed the droop lever up to retract the droops this would have been noticed by P3 Simon Ticehurst (who was more experienced and supervising Keighley) and Captain John Collins in the observer seat and as within seconds the stall warning horn, warning lights and stall recovery systems activated they would have been immediately alerted to a critical airspeed situation and would have checked the droops and extended them again. This also applies to Key who was supposed to be having a heart attack (medical opinion on Keys health at the enquiry was wildly divergent at worst it appears that Key might have been suffering from some discomfort like heartburn.) but if Key had retracted the droops the same applies the droops would have been extended again.

My hypothesis, as Aileron Drag puts it, is that Keighley did not mistake the command but did exactly as he was told and put in presumably, as it was a four digit input 06.00 into the height select panel but while he was twisting the knob due to the turbulence he knocked the lever out of position and the droops retracted but this was not visible to the other pilots. This is why no stall recovery procedures were initiated and why all the pilots assumed the stall recovery systems had activated without reason and why Key dumped the stall recovery systems and carried on trying to climb the aircraft. My hypothesis appears also born out by, I am afraid, by a rather grim piece of information. Captain John Collin’s body position in the cockpit after the crash indicated that he was leaning forward staring at the centre console and sources close to events suggest that he was the one that actually locked the lever back into place. I assume because he had taken a closer look at the droops lever and had seen what the problem was and extended the droops again but sadly too late.

This seems to be a good point to wind up and see if any Trident Pilots think my explanation of events could have any validity. If they do this raises other questions about the enquiry itself more appropriate for another post and, of course, the cause of the crash was not pilot error but a fundamental design/layout fault in the Trident cockpit.

JohnAndEmma
26th Sep 2013, 17:39
I am new to these forums and also intrigued by this accident. In the other thread
G-ARPI - The Trident Tragedy: 40 years ago today (http://www.pprune.org/aviation-history-nostalgia/488300-g-arpi-trident-tragedy-40-years-ago-today-5.html)
I have submitted a post which summarizes a notion that Captain Key's airspeed indicator was erroneously reading on the high side. This idea did not originate with me, but had been extensively considered in a book, as indicated in my other post. It is indeed an enduring mystery as to why Ticehurst - who in his P3 position should have been monitoring cockpit activities - did not notice the droop retraction and associate it with the stall warnings.

scotbill
27th Sep 2013, 07:38
When questions are raised about P3's monitoring of the droop reaction, it must be remembered that at the time the squawk code was not given till after TO.

As I recall through the blur of 40 years there were only a few seconds between climb clearance and squawk being given and the retraction of the droop. In these seconds, P3 duties required him to write down the clearance and select the squawk.

John Collins was a Vanguard training captain and an ex-Trident pilot. I have always believed that he did in fact spot the mis-selection and made a desperate attempt to rectify matters.

The suggestion at the enquiry that he might have been larking about distracting the crew at a critical stage of flight was a deeply offensive example of the level that lawyers will sink to in attempts to avoid blame for their clients.

blind pew
27th Sep 2013, 08:22
Ticehurst never saw the erroneous movement by keighley because we had a stupid SOP of writing down every clearance by EVERY pilot .......
IMHO jerry believed he had been ordered to retract the droop (instead of putting the reclearance in the box)....after Key made the order he would have turned to write the clearance down.
jerry, like myself, was taught that the stall system often malfunctioned and if the push went off then dump the system.
It is significant that none of our course were called to give evidence by the inquiry...
I have covered this in my autobiography...

HEATHROW DIRECTOR
27th Sep 2013, 09:30
<<Over the years I have spoken to quite a few airline captains about the Papa India disaster and all seem to agree that what happened was that Captain Stanley Key following re clearance by ATC from 1500ft to 6000ft >>

Where did the "1500 ft" bit come in please? The crew reported "passing 1500 ft climbing". The aircraft was following a Standard Instrument Departure and would not have stopped at nor been cleared to 1500 ft except for exceptional reasons. How do I know this? Because I cleared it for take-off and was involved in the investigation. I also have the official report in my hand. I did not instruct the crew to maintain 1500ft, nor did London Radar. As far asI recall, the only mention of "1500ft" was by the BBC air correspondent. Where he got it from I have no idea.

DaveReidUK
27th Sep 2013, 10:01
Where did the "1500 ft" bit come in please?The OP has long since gone (that "1500ft" quote is from a post more than a year ago), so I doubt you'll get an answer to your question ...

bean
28th Sep 2013, 16:57
The 1500 feet confusion is related to Captain Keys' first call to LATCC when he reported passing 1500. In reply they were recleared to FL60 and given a squawk. The droop retraction occured immediately after this. See page 5 of the
report.

DaveReidUK
28th Sep 2013, 23:26
In reply they were recleared to FL60 and given a squawk.The confusion appears to have arisen from the incorrect assertion that the term "recleared" (see above) was used, which might be interpreted as implying a prior clearance to a lower level. As HD has pointed out, that wasn't the case as the aircraft was already cleared by default to follow the SID, subject to its height restrictions.

The official report simply says "the aircraft was cleared to FL60".

777fly
29th Sep 2013, 00:26
I was a Trident copilot 1967-75. In reply to the original question of this post:
As I recall, if the droop lever was moved sideways out of its extend position detent with the heel of the hand, rather than being gripped firmly, it would spring to a position 2-3 inches towards the retract position. The droop did not start to retract until the lever was pushed further forward against a resistance. Hope this helps.

bean
29th Sep 2013, 01:45
Yes they were cleared initially to a lower altitude/level but it shoud have been to the max altitude/level of the SID

HEATHROW DIRECTOR
29th Sep 2013, 07:04
Bean... what lower altitude and by whom? They were cleared to the SID altitude and reported passing 1500 feet, which is pretty standard.

Allan Lupton
29th Sep 2013, 08:29
Do you not think that raking over this tragedy yet again is both pointless and tasteless?
Many of the theories advanced in this thread (and the other) show little understanding of how different flying aeroplanes is now, compared to how it was in the 1960s/70s.

HEATHROW DIRECTOR
29th Sep 2013, 08:47
<<Do you not think that raking over this tragedy yet again is both pointless and tasteless?>>

I do; I think it's uncalled for and some are trying to make something out of nothing. I shall contribute no further.

DaveReidUK
29th Sep 2013, 08:56
Many of the theories advanced in this thread (and the other) show little understanding of how different flying aeroplanes is now, compared to how it was in the 1960s/70s.Well there's only one theory proposed in this thread (though I share your view of it).

But in general, I think it does no harm to revisit previous accident investigations, with the benefit of hindsight, to see whether the lessons that should have been learned were or not.

Those who cannot remember the past are condemned to repeat it, as the saying goes. I certainly remember Staines well - I was working for BEA at the time (coincidentally on Trident major checks, so I know the type well).

Discorde
29th Sep 2013, 10:38
We might be dealing with inexplicable human fallibility here, when professional, competent and conscientious (and non-fatigued) people make errors or omissions for no apparent reason.

I recall an incident when, following push-back and engine start, one of our generators did not come on line. I asked the F/O to reset it and watched him press the IDG disconnect switch instead of the gen reset. I remember a part of my brain thinking 'that's not right, is it?' but by the time I made a comment the F/O had already realised his error and apologised profusely. We taxied back onto stand to have the engineers reconnect the IDG. When the F/O again apologised I replied that I shared the culpability because I did not prevent the mis-selection.

We admitted our mistake to the engineer, who gave us that 'pilots - what a bunch of wallies' look that most of us have experienced at one time or another.

Result: two chastened pilots and 10-minute delay to departure.

Shaggy Sheep Driver
29th Sep 2013, 18:39
IDG? Wot that?

bcgallacher
29th Sep 2013, 19:04
Integrated Drive Generator - If I recall the Trident had CSD's and separate generators. CSD - Constant Speed Drive.

777fly
29th Sep 2013, 19:44
I would have thought that my reply @ #14 would be sufficient to close this thread...? In addition, the detented droop lever was far enough back not to interfere with autopilot panel selections and, in any case, required some force to move it inboard, hence my 'heel of the hand' comment.. I flew G-ARPI many times, including an off runway landing accident, and flew with Captain Key on several occasions. I subscribe to the 'put it in' theory, whereby an altitude select directive was misinterpreted as a droop retract order. Stan could be authoratitive and intimidating to a junior second officer, but he was good family man with a kindly side, not often seen.

DaveReidUK
29th Sep 2013, 22:25
I would have thought that my reply @ #14 would be sufficient to close this thread...?

Welcome to PPRuNe.

777fly
30th Sep 2013, 21:05
Amen to that..