Trident autothrust system and autoland
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I had 2 engine failures in my career, both on T3's. Both were on rotation and both when I happened to be handling pilot. On neither occasion was there any problem with climb rate, although one was GLA-LHR and the second LHR-GLA, so not particularly heavy. The controls felt a bit wishy washy compared to normal, but no problem.
The first was #2 in YZ in June '76, my logbook tells me. As I rotated there was a loud muffled bang and I felt the control column being pushed forward, immediately followed by it being pulled back, then returning to the trimmed position. I had to resist the forces quite strongly to keep the column where I wanted it to maintain attitude during the rotation.
The aircraft had had a history of yellow hydraulics problems on initial climb, so P1&P3 looked up to the hyd levers for the stuck valve light, as I said check the hydraulics as I felt the forces through the column. Nothing there, no yaw of course, I glanced at the engine instruments and saw the TGT of #2 off the clock. No fire, shut down and return, right hand visual circuit to 06.
The second in VF in Jan '80
(With PMc). #1 blew up on rotation, with an incredibly long and loud graunching sound - it sounded like, and felt through the controls, and I thought, the U/C had collapsed as I rotated. It felt to me like we were being 'held' on the ground by the collapsed oleos dragging along the runway, and I remember being slightly surprised to see a positive rate of climb as the rotation progressed and we eventually got airborne. PMc thought we had hit a vehicle. Again no climb problems.
I remember thinking after the second one, this was the classic scenario, just what we do in the Sim, an engine failing on rotation, yet neither of these was anything like I had experienced in 12 years on simulator checks to date. Because of what else was happening, and the visual, tactile and aural clues we were getting, on both occasions, with no fire bell, not one crew member's first thought was that we were experiencing an engine failure - although it was very quickly picked up.
Still got some melted fan blades from both incidents.
The first was #2 in YZ in June '76, my logbook tells me. As I rotated there was a loud muffled bang and I felt the control column being pushed forward, immediately followed by it being pulled back, then returning to the trimmed position. I had to resist the forces quite strongly to keep the column where I wanted it to maintain attitude during the rotation.
The aircraft had had a history of yellow hydraulics problems on initial climb, so P1&P3 looked up to the hyd levers for the stuck valve light, as I said check the hydraulics as I felt the forces through the column. Nothing there, no yaw of course, I glanced at the engine instruments and saw the TGT of #2 off the clock. No fire, shut down and return, right hand visual circuit to 06.
The second in VF in Jan '80
(With PMc). #1 blew up on rotation, with an incredibly long and loud graunching sound - it sounded like, and felt through the controls, and I thought, the U/C had collapsed as I rotated. It felt to me like we were being 'held' on the ground by the collapsed oleos dragging along the runway, and I remember being slightly surprised to see a positive rate of climb as the rotation progressed and we eventually got airborne. PMc thought we had hit a vehicle. Again no climb problems.
I remember thinking after the second one, this was the classic scenario, just what we do in the Sim, an engine failing on rotation, yet neither of these was anything like I had experienced in 12 years on simulator checks to date. Because of what else was happening, and the visual, tactile and aural clues we were getting, on both occasions, with no fire bell, not one crew member's first thought was that we were experiencing an engine failure - although it was very quickly picked up.
Still got some melted fan blades from both incidents.
Last edited by Hobo; 13th Dec 2010 at 16:15. Reason: added detail
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Fascinating to read these insights on the Trident from you guys who do the pedalling.
From a pax point of view I always enjoyed flying in the Trident (moreso than the S1-11), always comfortable and seemed to handle turbulence well and of course those were the days when full service airline meant just that!!
On my earlier question about the 3 pilot crew, who decide which crew member would be P2 or P3? Could P3 count his hours sitting in the middle seat watching the guages.? Did P2 and P3 change seats with each sector?
From a pax point of view I always enjoyed flying in the Trident (moreso than the S1-11), always comfortable and seemed to handle turbulence well and of course those were the days when full service airline meant just that!!
On my earlier question about the 3 pilot crew, who decide which crew member would be P2 or P3? Could P3 count his hours sitting in the middle seat watching the guages.? Did P2 and P3 change seats with each sector?
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Not wanting to get in the way of slast's story, but I have a question about the Trident.
I flew as SLF on this type at least a couple of dozen times, and every time I was in a seat that had a view of the wing I noticed that the aileron was constantly moving. Not in a random fashion, but systematically up and down a few degrees pausing for a second or so at the end of each move, with an attendant roll back and forth. The roll was most noticeable if the sun was casting shadows inside the cabin which moved up and down - it was a bit like being on a ship.
I saw this often enough for it to be a norm rather than a particular aircraft with a lazy autopilot.
Anyone else notice this?
I flew as SLF on this type at least a couple of dozen times, and every time I was in a seat that had a view of the wing I noticed that the aileron was constantly moving. Not in a random fashion, but systematically up and down a few degrees pausing for a second or so at the end of each move, with an attendant roll back and forth. The roll was most noticeable if the sun was casting shadows inside the cabin which moved up and down - it was a bit like being on a ship.
I saw this often enough for it to be a norm rather than a particular aircraft with a lazy autopilot.
Anyone else notice this?
p2/p3
Wookey,
The Gripper in BA service was unusual in that all the First Officers were licensed in both the copilot and flight engineer seats. Typically (unless there was a training or other requirement for one pilot to be in a particular seat) the two F/Os would toss a coin to decide who sat where for the first sector and then changed seats each leg. The P3 was fully integrated into the overall flying tasks rather than "watching the gauges", and not licensed as a Flight Engineer who could carry out additional engineering tasks on turnarounds. So time as P3 was counted fully as "Copilot" hours.
With experienced crews and suitable conditions, many captains operated a leg and leg basis that meant that on a three sector day which was pretty common everyone got a takeoff and a landing in the course of the day.
The Gripper in BA service was unusual in that all the First Officers were licensed in both the copilot and flight engineer seats. Typically (unless there was a training or other requirement for one pilot to be in a particular seat) the two F/Os would toss a coin to decide who sat where for the first sector and then changed seats each leg. The P3 was fully integrated into the overall flying tasks rather than "watching the gauges", and not licensed as a Flight Engineer who could carry out additional engineering tasks on turnarounds. So time as P3 was counted fully as "Copilot" hours.
With experienced crews and suitable conditions, many captains operated a leg and leg basis that meant that on a three sector day which was pretty common everyone got a takeoff and a landing in the course of the day.
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slast
Thanks for the explanation
TRC
I never really noticed this and I probably flew several times a month most on Tridents for maybe 10 years. But then maybe I was just enjoying the full service too much to notice !! Be interesting to hear if the 'pros' have any insight into this
Thanks for the explanation
TRC
I never really noticed this and I probably flew several times a month most on Tridents for maybe 10 years. But then maybe I was just enjoying the full service too much to notice !! Be interesting to hear if the 'pros' have any insight into this
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TRC Unlike some types (eg 737) you couldn't see the wings from the flight deck windows. I was never aware of what you describe.
...regarding the climb performance, the standing joke was:-
Scottish -".... can you make 300 or above by the Cross*?"
Trident - " Not even Northbound."
* Dean Cross - VOR about 80 nms South of GLA/EDI
...regarding the climb performance, the standing joke was:-
Scottish -".... can you make 300 or above by the Cross*?"
Trident - " Not even Northbound."
* Dean Cross - VOR about 80 nms South of GLA/EDI
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I too spent 9 happy years on the Trident mainly Threes and don't recognise some of the adverse comments made. As conveyed so well by Steve, the problems of lack of thrust were of BEA's making - but entering a descent after boost engine shutdown - absolute tosh. As for its flying qualities they were superb - and I've seen it up to the high subsonics, with no signs of mach buffet or need for artificial devices. By contrast, the Tristar required the terrifying Recovery Speed Brake and the DC10 hit a wall above M.85 needing bank angle limitation to obviate buffet during cruise.
How good to see Pete and Steve going strong though Pete barely recognisable without pipe.
How good to see Pete and Steve going strong though Pete barely recognisable without pipe.
Hey! I gave up the pipe long before I retired
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I never really noticed this ........
I was never aware of what you describe
I was never aware of what you describe
It always fascinated me - maybe I should have taken a better book..
Reverse idle, politics and incident reports
It was a dark and stormy night……
Actually we’ll start a bit earlier. Remember the sequence post WW2 – the old Imperial Airways was relaunched by the new Labour government as BOAC and BEA. I think that given the chance some of the more radical thinkers went to develop BEA’s new high density European network while the traditionalists stayed with the old Imperial “flag carrier” tasks of BOAC. In flight ops certainly BEA had a lot of challenges including a high exposure to poor visibility ops and was prepared to develop new thinking on a variety of issues including training flight deck procedures and so on.
BEA’s management seemed to take the view that if existing solutions don’t fix a problem, you need to find a new solution even if goes against tradition. BOAC’s seemed to be that its practices were the best there could be, and required extremely high individual performance: in general, safety problems were due to failure to meet those standards, and that could be fixed by dealing with individuals by disciplinary or other means. There were thus two very different philosophies about how to achieve the best safety results in the two corporations.
So when the decision was taken to create BA by bringing them back under a single roof, but retaining “autonomous operating divisions”, what had previously been a legitimate rivalry between two separate organisations became entrenched internal warfare. This led to weird situations and turf wars where groups which were supposed to be on the same side were actually allied with their nominal “enemies”, e.g. in discussions with the pilots it wasn’t so much “BA management vs BALPA for BA pilots” as “Longhaul pilots and management” vs “shorthaul pilots and management” with leaks and “conspiracies” galore, especially before the privatisation of BA forced a proper merger to take place (eventually).
One of BA’s best aspects has always been having an independent Safety Branch, independent of departmental managements and reporting directly to the Board and giving the Board clear overall responsibility for corporate safety. The Air Safety Adviser therefore carries a lot of “clout” which is good in many ways - but can have drawbacks.
As I said earlier, BEA was never averse to making radical changes if it thought them necessary and the need to fix the low visibility ops problems led to the autoland programme which among other things required validation of test landings. This in turn led to the development of much more advanced flight recorders and in particular the Quick Access Recorder, which could be analysed after every flight.
There was also a difference in attitude between the pilots’ representatives in BALPA on the technical/safety side and those on the industrial side, with again the “techies” tending to be more open to changes while the industrial guys were very suspicious of them especially when initiated by management. Anyway, over the years collectively BALPA, BA and the CAA developed understandings about the use of flight recorders for ACCIDENT investigation, about confidential “no blame” incident reporting which basically led the world. This then led to an agreement with BA about the use of FDRs for INCIDENT analysis, and which has eventually led toroutine use for preventive measures in QAR programmes etc.
It was basically BALPA and BA which did the ground-breaking work on all that. So all this was followed with interest elsewhere, especially by NASA who were keen to introduce similar confidential anonymous reporting and so forth in the US, against a lot of opposition from many in ALPA, as well as some voices in the FAA and DOT, who were concerned about the legal implications etc. So how BA’s agreement worked was seen as setting some pretty important precedents.
So much for the background - now to the “dark and stormy night”…... and a T3 is making an approach at a Spanish coastal airport. There is a big T-storm approaching the far end of the runway. The Trident NORMAL landing procedure as noted earlier in this thread, is to close the throttles and select reverse idle (pod engines obviously) IN THE FLARE. This was actioned by the P2 as non-handling pilot, the handling pilot P1 having both hands on the yoke. Optionally one could then select FULL reverse while in the flare, and this was a very effective technique on short or wet runways as the Trident had pretty mediocre brakes. So the crew brief for this technique, in the flare the call is “Power off and full reverse”. The P2 closes the thrust levers and immediately pulls up the reverser levers, the buckets deploy and the pod engines never spool down but increase RPM from the approach value to close to full power for a few moments, then back to idle as the aircraft slows. The aircraft has rolled into a wall of water at touchdown and during the rollout the P3 notices that the antiskid stops working on the right gear. Roll onto the ramp, the rain is bucketing down and an engineer comes aboard to report that two tyres are burst and four are badly scalded.
Then all the lights go out in the region as the rainwater floods the area. So the a/c is on the ground for the night while some new tyres are shipped down. The crew write up on of the new Mandatory Occurrence forms for the burst tyre incident and return to base, and life goes on as normal.
About a month later the Captain gets a summons to see his manager, who has a “confidential” engineer’s analysis of the QAR, saying that (inter alia) the tyres were burst because “the pilots had not used the recommended landing technique of selecting reverse IDLE in the flare. In a sort of drumhead court-martial, the Captain is suspended and is required to do a base check before being allowed back on the line.
At this point the s*** hit the fan because they had effectively taken disciplinary action against an employee without complying with any of the requirements of their own disciplinary procedures. Not only that, the pilot involved happened to be one of the BALPA reps involved in developing the agreement on the use of FDRs for incident analysis, and the management have just busted every clause in it!
The whole event demonstrated why the agreement had all the clauses about getting ALL the information, and involving all parties including the crew members concerned, BEFORE reaching a conclusion as to what happened. They had just gone raw FDR > engineers interpretation > management > disciplinary action. (Of course the bare statement about not using the reverse IDLE was correct, unfortunately the trace does not contain the reverser position.)
So what was the politics behind it? One interpretation was it was an opportunity to make an example: “OK, if we can get a BALPA rep right at the start we’ll never have a problem using FDR info to prove pilots haven't complied with recommended procedures”. More likely in my view was that there had already been a major difference of view at top level about the company philosophy. The air safety adviser, was ex BOAC and seemed to believe that pilots who had incidents and had not followed recommended procedures to the letter should be disciplined. The ex BEA chief pilot I think took a much more nuanced view of the complexities of everyday operation and was actually reluctant to use disciplinary action per se. I suspect the chief pilot knew the engineer’s analysis was automatically sent to the board’s Air Safety adviser, and decided to pre-empt any criticism (“here’s another of your pilots screwing up, what are you going to do about it?”) and clear his own yard-arm by just getting the pilot re-confirmed as competent, so he could tell the Air Safety head where to go. But it didn’t work out quite like that because he was out on a limb on both the actual event and the procedures.
Internally the upshot was a letter of apology from the Deputy Flight Ops Director to the Captain concerned (via BALPA!) and an acknowledgement that the whole thing had been grossly mishandled, to the great embarrassment of the company, followed shortly after by some changes of management pilots. However, it nearly caused the whole agreement to come off the rails, just at the time when NASA was trying to convince US ALPA that airlines and authorities could be trusted to use safety data responsibly and not use it to screw individuals who took part. When Charlie Billings who was running a lot of that activity heard about what had happened, he was afraid that word would soon get out in the wider industry. I thought he was going to have a heart attack, as the BA/BALPA agreement was being held up as a global example of how this stuff could be made to work, and here was the first example of what actually happened! Fortunately we damped it down and things proceeded smoothly in the long run, but it could easily have turned out differently.
Actually we’ll start a bit earlier. Remember the sequence post WW2 – the old Imperial Airways was relaunched by the new Labour government as BOAC and BEA. I think that given the chance some of the more radical thinkers went to develop BEA’s new high density European network while the traditionalists stayed with the old Imperial “flag carrier” tasks of BOAC. In flight ops certainly BEA had a lot of challenges including a high exposure to poor visibility ops and was prepared to develop new thinking on a variety of issues including training flight deck procedures and so on.
BEA’s management seemed to take the view that if existing solutions don’t fix a problem, you need to find a new solution even if goes against tradition. BOAC’s seemed to be that its practices were the best there could be, and required extremely high individual performance: in general, safety problems were due to failure to meet those standards, and that could be fixed by dealing with individuals by disciplinary or other means. There were thus two very different philosophies about how to achieve the best safety results in the two corporations.
So when the decision was taken to create BA by bringing them back under a single roof, but retaining “autonomous operating divisions”, what had previously been a legitimate rivalry between two separate organisations became entrenched internal warfare. This led to weird situations and turf wars where groups which were supposed to be on the same side were actually allied with their nominal “enemies”, e.g. in discussions with the pilots it wasn’t so much “BA management vs BALPA for BA pilots” as “Longhaul pilots and management” vs “shorthaul pilots and management” with leaks and “conspiracies” galore, especially before the privatisation of BA forced a proper merger to take place (eventually).
One of BA’s best aspects has always been having an independent Safety Branch, independent of departmental managements and reporting directly to the Board and giving the Board clear overall responsibility for corporate safety. The Air Safety Adviser therefore carries a lot of “clout” which is good in many ways - but can have drawbacks.
As I said earlier, BEA was never averse to making radical changes if it thought them necessary and the need to fix the low visibility ops problems led to the autoland programme which among other things required validation of test landings. This in turn led to the development of much more advanced flight recorders and in particular the Quick Access Recorder, which could be analysed after every flight.
There was also a difference in attitude between the pilots’ representatives in BALPA on the technical/safety side and those on the industrial side, with again the “techies” tending to be more open to changes while the industrial guys were very suspicious of them especially when initiated by management. Anyway, over the years collectively BALPA, BA and the CAA developed understandings about the use of flight recorders for ACCIDENT investigation, about confidential “no blame” incident reporting which basically led the world. This then led to an agreement with BA about the use of FDRs for INCIDENT analysis, and which has eventually led toroutine use for preventive measures in QAR programmes etc.
It was basically BALPA and BA which did the ground-breaking work on all that. So all this was followed with interest elsewhere, especially by NASA who were keen to introduce similar confidential anonymous reporting and so forth in the US, against a lot of opposition from many in ALPA, as well as some voices in the FAA and DOT, who were concerned about the legal implications etc. So how BA’s agreement worked was seen as setting some pretty important precedents.
So much for the background - now to the “dark and stormy night”…... and a T3 is making an approach at a Spanish coastal airport. There is a big T-storm approaching the far end of the runway. The Trident NORMAL landing procedure as noted earlier in this thread, is to close the throttles and select reverse idle (pod engines obviously) IN THE FLARE. This was actioned by the P2 as non-handling pilot, the handling pilot P1 having both hands on the yoke. Optionally one could then select FULL reverse while in the flare, and this was a very effective technique on short or wet runways as the Trident had pretty mediocre brakes. So the crew brief for this technique, in the flare the call is “Power off and full reverse”. The P2 closes the thrust levers and immediately pulls up the reverser levers, the buckets deploy and the pod engines never spool down but increase RPM from the approach value to close to full power for a few moments, then back to idle as the aircraft slows. The aircraft has rolled into a wall of water at touchdown and during the rollout the P3 notices that the antiskid stops working on the right gear. Roll onto the ramp, the rain is bucketing down and an engineer comes aboard to report that two tyres are burst and four are badly scalded.
Then all the lights go out in the region as the rainwater floods the area. So the a/c is on the ground for the night while some new tyres are shipped down. The crew write up on of the new Mandatory Occurrence forms for the burst tyre incident and return to base, and life goes on as normal.
About a month later the Captain gets a summons to see his manager, who has a “confidential” engineer’s analysis of the QAR, saying that (inter alia) the tyres were burst because “the pilots had not used the recommended landing technique of selecting reverse IDLE in the flare. In a sort of drumhead court-martial, the Captain is suspended and is required to do a base check before being allowed back on the line.
At this point the s*** hit the fan because they had effectively taken disciplinary action against an employee without complying with any of the requirements of their own disciplinary procedures. Not only that, the pilot involved happened to be one of the BALPA reps involved in developing the agreement on the use of FDRs for incident analysis, and the management have just busted every clause in it!
The whole event demonstrated why the agreement had all the clauses about getting ALL the information, and involving all parties including the crew members concerned, BEFORE reaching a conclusion as to what happened. They had just gone raw FDR > engineers interpretation > management > disciplinary action. (Of course the bare statement about not using the reverse IDLE was correct, unfortunately the trace does not contain the reverser position.)
So what was the politics behind it? One interpretation was it was an opportunity to make an example: “OK, if we can get a BALPA rep right at the start we’ll never have a problem using FDR info to prove pilots haven't complied with recommended procedures”. More likely in my view was that there had already been a major difference of view at top level about the company philosophy. The air safety adviser, was ex BOAC and seemed to believe that pilots who had incidents and had not followed recommended procedures to the letter should be disciplined. The ex BEA chief pilot I think took a much more nuanced view of the complexities of everyday operation and was actually reluctant to use disciplinary action per se. I suspect the chief pilot knew the engineer’s analysis was automatically sent to the board’s Air Safety adviser, and decided to pre-empt any criticism (“here’s another of your pilots screwing up, what are you going to do about it?”) and clear his own yard-arm by just getting the pilot re-confirmed as competent, so he could tell the Air Safety head where to go. But it didn’t work out quite like that because he was out on a limb on both the actual event and the procedures.
Internally the upshot was a letter of apology from the Deputy Flight Ops Director to the Captain concerned (via BALPA!) and an acknowledgement that the whole thing had been grossly mishandled, to the great embarrassment of the company, followed shortly after by some changes of management pilots. However, it nearly caused the whole agreement to come off the rails, just at the time when NASA was trying to convince US ALPA that airlines and authorities could be trusted to use safety data responsibly and not use it to screw individuals who took part. When Charlie Billings who was running a lot of that activity heard about what had happened, he was afraid that word would soon get out in the wider industry. I thought he was going to have a heart attack, as the BA/BALPA agreement was being held up as a global example of how this stuff could be made to work, and here was the first example of what actually happened! Fortunately we damped it down and things proceeded smoothly in the long run, but it could easily have turned out differently.
Last edited by slast; 13th Dec 2010 at 17:45.
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The Gripper in BA service was unusual in that all the First Officers were licensed in both the copilot and flight engineer seats. Typically (unless there was a training or other requirement for one pilot to be in a particular seat) the two F/Os would toss a coin to decide who sat where for the first sector and then changed seats each leg. The P3 was fully integrated into the overall flying tasks rather than "watching the gauges", and not licensed as a Flight Engineer who could carry out additional engineering tasks on turnarounds. So time as P3 was counted fully as "Copilot" hours.
With experienced crews and suitable conditions, many captains operated a leg and leg basis that meant that on a three sector day which was pretty common everyone got a takeoff and a landing in the course of the day.
With experienced crews and suitable conditions, many captains operated a leg and leg basis that meant that on a three sector day which was pretty common everyone got a takeoff and a landing in the course of the day.
Steve, your post reminds us that a lasting legacy of the Trident was that on completion of the autoland proving trials, the company found themselves with a redudent 64 channel data recorder on the entire fleet. This data could have been used in a variety of ways, some of them harsh & disciplinarian. However, BEA and BALPA came up with the enlightened SESMA programme which in my view is one of the greatest single contributors to air safety.
Then again Papa India, the main cause of which was the Tridents big design flaw - not incorporating flap & droop into a single lever, brought about the introduction of CVR
Then again Papa India, the main cause of which was the Tridents big design flaw - not incorporating flap & droop into a single lever, brought about the introduction of CVR
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I believe that John Cunningham himself didn't like the feline nickname at all - although my only contact with him was a passing "Hello Mr Cunningham" when he opened the Biggin Hill show about 10 years ago.
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...Tristar required the terrifying Recovery Speed Brake
The UKCAA always was a bit obtuse in the certification department...
