Staines, UK 1972, June 18th.
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@ Tubby Linton and WHBM
From memory, this switch determined whose heading/track select control (P1 or P2) was controlling the autopilot and flight director. In track mode the drift (sensed by the Doppler Janus system) was automatically applied to heading.
Lateral: possibly heading, but probably track, with crew own-navigating to Epson NDB.
Vertical: indicated airspeed lock, gradient of climb therefore dependent on thrust setting.
No; in the 'PI accident perhaps the well-documented breakdown in crew harmony might have resulted in P1 doing the R/T rather than P2.
Blind Pew's tech knowledge is almost certainly better than mine.
Logic suggests that 'unlucky aircraft' would be a rare freak of statistics rather than victims of some sort of malign force. And yet . . .
Trans-Canada Airlines CF-TJM ran off the end of R28R on 6 November 1963 (details from ASN and pics here) following a rejected take-off with insufficient runway distance remaining. The extensively damaged aircraft was rebuilt and returned to service, only to be destroyed in a training accident four years later.
Page Four mentions a switch in the P1 azimuth window. It states it was found in the starboard position after the crash but that it may have been moved due to the footprints found in the area and that it should have been in the port position. It all sounds very circumstantial to me and I doubt a modern enquiry would have believed this explanation. What exactly did it do?
When the autopilot was engaged what lateral and vertical modes would have been engaged? What was the vertical mode targeting? A vertical speed or based upon a speed reference?
Vertical: indicated airspeed lock, gradient of climb therefore dependent on thrust setting.
Was it normal practice for the PF also to do the RT?
Blind Pew's tech knowledge is almost certainly better than mine.
At the 'PI accident there was apparently considerable searching of engineering repair documents to see if anything arising from those could have contributed to the stall. A very unlucky aircraft.
Trans-Canada Airlines CF-TJM ran off the end of R28R on 6 November 1963 (details from ASN and pics here) following a rejected take-off with insufficient runway distance remaining. The extensively damaged aircraft was rebuilt and returned to service, only to be destroyed in a training accident four years later.
Thanks Discorde
to understand further especially P2 who was blamed by certain parties for lack of ability; I did my baron flying with him, a guy ex fleet air arm chippies who chucked in his commission and a horny old hurribomber pilot who had left a wing tip and aileron on a tree stump and if it wasn’t for the direction the valley turned he wouldn’t have got out of it. After my instrument rating I had lots of hours to burn..I had seriously messed up on tests ..and I went over the new forest and did a few straight stalls..one of which flicked and I ended up fully inverted looking up at my brief case. I told pat about it and we looked at the aircraft which was obviously bent, probably from a cocked up barrel roll..and pat said to me « ace if bullsh@t was a trombone you would be a full brass band »
The 4 of us were permitted to do one night stop and we chose Amsterdam and the red light area with quite a few beers. The morning I flew Ams - Ostende where Jerry took over to fly airways through a virulent front back to hamble where the rest of the fleet was grounded. We got into some serious sh@t and Jerry said to pat Should I reduce to turbulence speed..NO… a minute or so later there was an almighty bang, a scream and pat yanked back the throttles whilst Jerry continued flying.
lesson two
the atmosphere in BEA was extremely toxic and it was obvious that we weren’t wanted and that many didn’t want us in the RHS.
I was at base with Jerry, he was paired with another course mate who went onto the VC10 with me which was an experiment by BOAC to take us directly into the rhs and part 1..I failed my first check.
The 4 of us came back from prestwick for the Trident 2 differences course but towards the end we were told that the board of trade would not accept our partial training..you will read there was an argument in the inquiry where lord lane said he believed captain holdstock..the guy who had visited the latter’s office was the guy who put down land flap at noise point instead of selecting it up..he went on to fly Concorde.
I flew with number 2 in management and a turncoat who also became a big cheese in my first weeks..they would not let me fly the aircraft except with the autopilot engaged and way above Terra firma. That was the sort of trust they had in us before the accident.
We all tried fiddling with the flap lever to see if it would inadvertently move but it wouldn’t.
Based on my experience Key, like Several others who found flying the trident at speeds way on the backside of the drag curve, plugged in the autopilot very low and whilst accelerating which led to it pitching up, loosing speed..pitching down..la la la..the flaps were selected in at noise by Jerry and he would have throttled back..they got the clearance up to six zero which all three were required to write down on their NAV logs ..P3 on a table to his right and the others under their respective DV windows…and Key who had been recently refused a training appointment and not a happy bunny ordered Jerry to « put it in » and possibly pointed in the direction of the height acquire box adjacent to the droop lever. Under SOP it was Keys task ne Jerrys next task was to select the droop in, monitor the engines and his instruments.
It was a simple use of an abrivated command to select flight level six zero in the height acquire box being mistaken from select droop in..
At that early stage I certainly hadn’t managed to sort out a scanning system which included all of the front panel..a BEA special with the third horizon next to the captains left knee..
The last working accident investigator told me two snippets..the simulator did not replicate the aircraft in pitch and that a clever individual stuck a plastic bag over the levers to preserve the evidence coz it started to rain..this actually destroyed it.
lastly our union rep stated that by examining the bulbs they were able to ascertain which ones had been illuminated..if the filament had power it burnt.
.
to understand further especially P2 who was blamed by certain parties for lack of ability; I did my baron flying with him, a guy ex fleet air arm chippies who chucked in his commission and a horny old hurribomber pilot who had left a wing tip and aileron on a tree stump and if it wasn’t for the direction the valley turned he wouldn’t have got out of it. After my instrument rating I had lots of hours to burn..I had seriously messed up on tests ..and I went over the new forest and did a few straight stalls..one of which flicked and I ended up fully inverted looking up at my brief case. I told pat about it and we looked at the aircraft which was obviously bent, probably from a cocked up barrel roll..and pat said to me « ace if bullsh@t was a trombone you would be a full brass band »
The 4 of us were permitted to do one night stop and we chose Amsterdam and the red light area with quite a few beers. The morning I flew Ams - Ostende where Jerry took over to fly airways through a virulent front back to hamble where the rest of the fleet was grounded. We got into some serious sh@t and Jerry said to pat Should I reduce to turbulence speed..NO… a minute or so later there was an almighty bang, a scream and pat yanked back the throttles whilst Jerry continued flying.
lesson two
the atmosphere in BEA was extremely toxic and it was obvious that we weren’t wanted and that many didn’t want us in the RHS.
I was at base with Jerry, he was paired with another course mate who went onto the VC10 with me which was an experiment by BOAC to take us directly into the rhs and part 1..I failed my first check.
The 4 of us came back from prestwick for the Trident 2 differences course but towards the end we were told that the board of trade would not accept our partial training..you will read there was an argument in the inquiry where lord lane said he believed captain holdstock..the guy who had visited the latter’s office was the guy who put down land flap at noise point instead of selecting it up..he went on to fly Concorde.
I flew with number 2 in management and a turncoat who also became a big cheese in my first weeks..they would not let me fly the aircraft except with the autopilot engaged and way above Terra firma. That was the sort of trust they had in us before the accident.
We all tried fiddling with the flap lever to see if it would inadvertently move but it wouldn’t.
Based on my experience Key, like Several others who found flying the trident at speeds way on the backside of the drag curve, plugged in the autopilot very low and whilst accelerating which led to it pitching up, loosing speed..pitching down..la la la..the flaps were selected in at noise by Jerry and he would have throttled back..they got the clearance up to six zero which all three were required to write down on their NAV logs ..P3 on a table to his right and the others under their respective DV windows…and Key who had been recently refused a training appointment and not a happy bunny ordered Jerry to « put it in » and possibly pointed in the direction of the height acquire box adjacent to the droop lever. Under SOP it was Keys task ne Jerrys next task was to select the droop in, monitor the engines and his instruments.
It was a simple use of an abrivated command to select flight level six zero in the height acquire box being mistaken from select droop in..
At that early stage I certainly hadn’t managed to sort out a scanning system which included all of the front panel..a BEA special with the third horizon next to the captains left knee..
The last working accident investigator told me two snippets..the simulator did not replicate the aircraft in pitch and that a clever individual stuck a plastic bag over the levers to preserve the evidence coz it started to rain..this actually destroyed it.
lastly our union rep stated that by examining the bulbs they were able to ascertain which ones had been illuminated..if the filament had power it burnt.
.
Just in passing, for those who haven't seen the damage to PI in the 1968 Ambassador accident
The damage to the written off PT which was on the next stand was not dissimilar, but the aircraft was broken just forward of the engines, so obviously a much greater financial and structural loss.
The damage to the written off PT which was on the next stand was not dissimilar, but the aircraft was broken just forward of the engines, so obviously a much greater financial and structural loss.
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I'm sure I recall a news programme on BBC radio following the accident, in which they were speculating whether the earlier tailplane replacement could have been a contributing factor.
Lynx
There was a lot of speculation but you could be correct as a few years before a Trident 1 got a triple controls stuck valve warning which originated from the beam the elevator jacks were attached to sheared it's fastenings onto the tailplane allowing the elevator to float free. If it had happened any other time....
On another sad note P2s group had a round Robin originating from P2s sister who had seen a report of an infamous, self opinionated guy claiming to have been on a course with Jerry. This wasn't true and said retired captain turned up at the memorial service in his full uniform with his dart insignia. Never on Tridents.
upset a few people.
On another sad note P2s group had a round Robin originating from P2s sister who had seen a report of an infamous, self opinionated guy claiming to have been on a course with Jerry. This wasn't true and said retired captain turned up at the memorial service in his full uniform with his dart insignia. Never on Tridents.
upset a few people.
Just in passing, for those who haven't seen the damage to PI in the 1968 Ambassador accident
The damage to the written off PT which was on the next stand was not dissimilar, but the aircraft was broken just forward of the engines, so obviously a much greater financial and structural loss.
The damage to the written off PT which was on the next stand was not dissimilar, but the aircraft was broken just forward of the engines, so obviously a much greater financial and structural loss.
Coincidence I know but there was Comet 3 at RAE Bedford which had its tailplane removed by a Trident, the Comet being lined up on the runway while the Trident did a low approach, obviously a bit too low! . The damage was repaired by pinching the tailplane from one of the Comets which had been ferried into RAF Halton as an instructional airframe.
There was a lot of speculation but you could be correct as a few years before a Trident 1 got a triple controls stuck valve warning which originated from the beam the elevator jacks were attached to sheared it's fastenings onto the tailplane allowing the elevator to float free.
Jacks
Was my first of many technical courses over 50 years ago..sorry if I got the details wrong but sumfink broke.
As to the Bedford incident twas lots of big chiefs who were given their own discretion overshoot instruction.
Dave given that my memory of triple stuck valve flight controls warning is correct and that the tailplane incidence was driven by a screw jack how was it that it wasn't the elevator attachment? Don't suppose you have a schematic?
or maybe my incorrect use of terms as twas hydraulic rams?
As to the Bedford incident twas lots of big chiefs who were given their own discretion overshoot instruction.
Dave given that my memory of triple stuck valve flight controls warning is correct and that the tailplane incidence was driven by a screw jack how was it that it wasn't the elevator attachment? Don't suppose you have a schematic?
or maybe my incorrect use of terms as twas hydraulic rams?
Last edited by blind pew; 26th Jun 2022 at 06:13.
Dave given that my memory of triple stuck valve flight controls warning is correct and that the tailplane incidence was driven by a screw jack how was it that it wasn't the elevator attachment? Don't suppose you have a schematic?
or maybe my incorrect use of terms as twas hydraulic rams?
or maybe my incorrect use of terms as twas hydraulic rams?
The tailplane (in the days before we called them horizontal stabilizers) was moved by 3 hydraulic jacks in response to pitch (or a/p) inputs. The "elevator" wasn't really an elevator at all, it was a massive geared tab moved by a simple mechanical linkage to the stab. I suspect what you encountered was a failure of that linkage, which would indeed allow the tab to float freely.
I think your memory is playing tricks on you (or else mine is!) - I don't recall any screwjacks involved.
The tailplane (in the days before we called them horizontal stabilizers) was moved by 3 hydraulic jacks in response to pitch (or a/p) inputs. The "elevator" wasn't really an elevator at all, it was a massive geared tab moved by a simple mechanical linkage to the stab. I suspect what you encountered was a failure of that linkage, which would indeed allow the tab to float freely.
The tailplane (in the days before we called them horizontal stabilizers) was moved by 3 hydraulic jacks in response to pitch (or a/p) inputs. The "elevator" wasn't really an elevator at all, it was a massive geared tab moved by a simple mechanical linkage to the stab. I suspect what you encountered was a failure of that linkage, which would indeed allow the tab to float freely.
We used a wheel to set tailplane incidence which I presumed was linked to a screw jack but you would know better..the flight controls were fully hydraulic except for the addition of the air cylinder for the stick push which acted through the stick to effect the elevator through the hydraulics.
I presume you don't have any manuals but what I do remember was that it was extremely serious that it would have lost control of the aircraft in pitch.
Therefore the incident was likely to be the source of the article referred to earlier of loss of control caused by damage at the rear end..note not being specific as an old f@rt as all of us who flew the gripper then are.
BP,
The Trident stabilser (tailplane) trim worked differently compared to most other jet transports. DaveReidUK is correct. Alex Fisher describes some of the differences here:-
https://skybrary.aero/sites/default/...shelf/2627.pdf
The Trident stabilser (tailplane) trim worked differently compared to most other jet transports. DaveReidUK is correct. Alex Fisher describes some of the differences here:-
https://skybrary.aero/sites/default/...shelf/2627.pdf
Thanks Bergerie
Stand to be corrected but I seem to remember that we had to wind the trim wheel fully nose down on parking check. As Alex’s text states the elevator is moved by the trim tab. Now we all know BEA had some specials including the instrument panels and noise abatement procedures which it could be.
It could also be that I’m mixing up Douglas procedures but the shut down checklists don’t cover that.
My initial post was re a newspaper article and there was definitely an incident on landing when the flight controls disconnected themselves from the big big at the back end…
Looking at parked Tridents photos the stabs are all in fully nose down position.
It could also be that I’m mixing up Douglas procedures but the shut down checklists don’t cover that.
My initial post was re a newspaper article and there was definitely an incident on landing when the flight controls disconnected themselves from the big big at the back end…
Looking at parked Tridents photos the stabs are all in fully nose down position.
Tubby re autopilot
https://tonymadgehjg.proboards.com/t...trident-manual
The link is the most comprehensive data I can find which describes the autopilot operation inuding the azimuth switch.
Imput by some knowledgeable guys.
It also shows the after landing checklist Item of setting the tailplane to zero. It is very unlikely that this was a requirement if the whole lot was driven by an elevator tab as suggested. I asked a former colleague who was on a technical committee with Alex but he can't remember although he flew with a captain who had a triple flight controls warning in the flare as the elevator system failed.
As to comments about re trimming the elevator when in a flat spin.. all it will do is to keep your mind away from thinking this is going to hurt.
One of the guys who was a supervisory first officer described to me a stick push exercise where the aircraft wallowed on the verge of entering a deep stall, fortunately it slowly started to pitch nose down. Shortly after that the air exercise was abandoned.
On the DC9 we had an elevator boost system which activated to aid the tab controlled elevators to move as airflow at high angle of attack wasn't sufficient. The tailplane was controlled through screw jacks.
The link is the most comprehensive data I can find which describes the autopilot operation inuding the azimuth switch.
Imput by some knowledgeable guys.
It also shows the after landing checklist Item of setting the tailplane to zero. It is very unlikely that this was a requirement if the whole lot was driven by an elevator tab as suggested. I asked a former colleague who was on a technical committee with Alex but he can't remember although he flew with a captain who had a triple flight controls warning in the flare as the elevator system failed.
As to comments about re trimming the elevator when in a flat spin.. all it will do is to keep your mind away from thinking this is going to hurt.
One of the guys who was a supervisory first officer described to me a stick push exercise where the aircraft wallowed on the verge of entering a deep stall, fortunately it slowly started to pitch nose down. Shortly after that the air exercise was abandoned.
On the DC9 we had an elevator boost system which activated to aid the tab controlled elevators to move as airflow at high angle of attack wasn't sufficient. The tailplane was controlled through screw jacks.
