Barely controllable Tu-154 - another UA232
This scenario was raised in an aviation quiz I went to years ago. The solution was to lean into the middle of the cockpit and fly using the inboard horns of the control wheels: left hand on right prong of left wheel, right hand on left prong of right wheel. This will result in the aircraft doing what you expect, even though the wheels themselves are moving in the opposite direction.
I wonder if they had two cables, i.e. control cables (wire) crossed? Maybe they are coated different colors.
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Guys ... virtually nobody so far spoke of Dutch Roll.
For me it's a perfect display of this phenomon (and nicely undamped)
Something sure : as rudder inputs (careful and incremental) are used in experimental flight test to enter dutch roll, the answer is simple : don't use rudder to get out of it !! try with ailerons instead.
Now it's another story if rudder is the only control left .... then pilots will try their best.
A failed yaw damper will not help.
Now with functional controls - and probably even with a working YD, you will get this show with a pilot fighting like hell on the rudder, with no idea of what it's all about.
Or you will have a structural failure - especially if you perform full rudder eversals in succesion, for which no aircraft has ever been certified (test pilots are not suicidal)
As somebody said, the Hunter in approach configuration (gear and flaps down) could exhibit a wonderful and virtually undamped dutch roll.....
Typical of swept wings of old designs - and the Tu-154 has a big angle of them ....
A big problem in the airline sindustry is "experienced" pilots (thousands of hours on autopilot, reading the newspapers) considered that in case of turbulence, departure, excursion from normal parameters, they have to use rudder because for them it means "for the big boys" which they think they are.
Airliners are lost on a regular basis all over the world for that.
Dont'use rudder - Dont'use rudder - Dont'use rudder - Dont'use rudder ....
(except for crosswind landings, or air combat at slow speed, or being the tanker to stay aligned ...)
For me it's a perfect display of this phenomon (and nicely undamped)
Something sure : as rudder inputs (careful and incremental) are used in experimental flight test to enter dutch roll, the answer is simple : don't use rudder to get out of it !! try with ailerons instead.
Now it's another story if rudder is the only control left .... then pilots will try their best.
A failed yaw damper will not help.
Now with functional controls - and probably even with a working YD, you will get this show with a pilot fighting like hell on the rudder, with no idea of what it's all about.
Or you will have a structural failure - especially if you perform full rudder eversals in succesion, for which no aircraft has ever been certified (test pilots are not suicidal)
As somebody said, the Hunter in approach configuration (gear and flaps down) could exhibit a wonderful and virtually undamped dutch roll.....
Typical of swept wings of old designs - and the Tu-154 has a big angle of them ....
A big problem in the airline sindustry is "experienced" pilots (thousands of hours on autopilot, reading the newspapers) considered that in case of turbulence, departure, excursion from normal parameters, they have to use rudder because for them it means "for the big boys" which they think they are.
Airliners are lost on a regular basis all over the world for that.
Dont'use rudder - Dont'use rudder - Dont'use rudder - Dont'use rudder ....
(except for crosswind landings, or air combat at slow speed, or being the tanker to stay aligned ...)
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Coordinated use of rudder is required in gliders to counteract adverse yaw effect of the ailerons.
Stubby or swept wing aircraft use rudder for steering while taxying on the ground.
Stubby or swept wing aircraft use rudder for steering while taxying on the ground.
Having personally flown swept wing, T-tail jets similar to this aircraft, it appears to me that the Dutch-roll action (the aircraft's speed is too slow for true Dutch roll?) may be just be caused by a aileron-to-rudder cross-tie (normally active used in the lower end of the speed range) that is out of sync and/or reversed. That is what it looks like in the video sequence.
However, there seem to be several folk here with Tupolev hands-on experience, and their insight is useful. I look forward to finally hearing th official verdict!
However, there seem to be several folk here with Tupolev hands-on experience, and their insight is useful. I look forward to finally hearing th official verdict!
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Finally some official info -
according to the reported results of the investigation the incident was caused by the flight engineer mis-connecting one of the elements of the automatic on-board flight control system to the power supply.
according to the reported results of the investigation the incident was caused by the flight engineer mis-connecting one of the elements of the automatic on-board flight control system to the power supply.
From what I hear not the Flight Engineer on board but a Ground Engineer before the flight. Appears to be a translation/transmittal problem between the reports and the press, who were indicating the FE to be responsible. However, the connections involved point towards maintenance action on the ground and were not accessible (or reversible) by the FE.
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Interesting details emerging - it turns out the tech used common sense and connected a green wire to a green wire and red to red. Big mistake! The polarity needs to be reversed. Go figure...
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There was a fatal accident to a Tu 154 in Xian, China in 1992. From the Aviation Safety Network report:
The aircraft broke-up in flight and crashed about ten minutes after takeoff.
PROBABLE CAUSE: Auto-pilot induced oscillations caused the aircraft to shake violently. It appeared that the autopilot yaw-channel had been connected to the bank control and the bank-channel to the yaw controls. This was done the previous evening 'in the field' rather than in a workshop.
PROBABLE CAUSE: Auto-pilot induced oscillations caused the aircraft to shake violently. It appeared that the autopilot yaw-channel had been connected to the bank control and the bank-channel to the yaw controls. This was done the previous evening 'in the field' rather than in a workshop.
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There was an interview with the crew, taken by КП (Komsomolskaya Pravda :o) newspaper,
the Capt. referred to "two similar accidents in the TU history" - one in China - as noted above - and one sorry forgot where else.
But then the Capt. added he is not sure that's the same bug, as "both those two flights were in auto-pilot mode - while we were not!"
Then he said, naturally, "the commission will sort it out"
And separately noticed it could be those 3 wires set - red, green and yellow, connected reasonably, "while the factory must have planned that someone connects them not according to colour but according to the manual book" "it is very mis-leading and a protest was sent to the maker pointing out a normal person does not deliberately colour wires same colour which one wants NOT to be connected!!!"
But about causes he spoked briefly "commission" etc. their matter
Mostly about his impressions :o))))))) of the dis-obedient plane on hands.
That they wanted to go back home at once :o) but managed only from the third attempt. Apparently it only lasted 13 minutes, during which time they did 3 landing attempts, intense 13 minutes.
He said what scared him is all the devices kept showing that all goes OK - before the take-off and during the mad flight.
The "bort-engineer" crew member was saying he only watched the engines that they shouldn't save god stop was focused on that.
the Capt. referred to "two similar accidents in the TU history" - one in China - as noted above - and one sorry forgot where else.
But then the Capt. added he is not sure that's the same bug, as "both those two flights were in auto-pilot mode - while we were not!"
Then he said, naturally, "the commission will sort it out"
And separately noticed it could be those 3 wires set - red, green and yellow, connected reasonably, "while the factory must have planned that someone connects them not according to colour but according to the manual book" "it is very mis-leading and a protest was sent to the maker pointing out a normal person does not deliberately colour wires same colour which one wants NOT to be connected!!!"
But about causes he spoked briefly "commission" etc. their matter
Mostly about his impressions :o))))))) of the dis-obedient plane on hands.
That they wanted to go back home at once :o) but managed only from the third attempt. Apparently it only lasted 13 minutes, during which time they did 3 landing attempts, intense 13 minutes.
He said what scared him is all the devices kept showing that all goes OK - before the take-off and during the mad flight.
The "bort-engineer" crew member was saying he only watched the engines that they shouldn't save god stop was focused on that.
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It is good they didn't blame the crew as often happens, for ex in the same newspaper was an opposite example, of Russian sub that began hushing absent fire on board, by some automatic system, and many got poisoned by the fumes. During trials, the ship was built by order for India. The only one under criminal court hearings 2yrs later is still the Captain - absolutely no other suspects :o)
Though there is in the case his report that the fire-extinguishing computer system switches on and off as it likes, "in the condition the vessel is - it poses deadly threat to the crew if it goes at sea". The factory maker read that report and ordered trials :o)
Plus the fire hushing mixture was dissolved with smth cheap and stupid, 1/3 - in transit to the sub (read stolen. documented) - which caused poisonous fumes.
The only thing that saves the head of that Captain so far is Indian buyer, who says they won't take the sub unless that captain who brought the ship home altogether in spite of dear factory mis-deeds goes in the "package" together with their dear purchase.
Though there is in the case his report that the fire-extinguishing computer system switches on and off as it likes, "in the condition the vessel is - it poses deadly threat to the crew if it goes at sea". The factory maker read that report and ordered trials :o)
Plus the fire hushing mixture was dissolved with smth cheap and stupid, 1/3 - in transit to the sub (read stolen. documented) - which caused poisonous fumes.
The only thing that saves the head of that Captain so far is Indian buyer, who says they won't take the sub unless that captain who brought the ship home altogether in spite of dear factory mis-deeds goes in the "package" together with their dear purchase.
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What an amazing example of superb flying skills.
I tend to respect folks that when proved to be wrong hold up their hands and apologise!!
Might I respectfully suggest all those that thought the video was fake or accused that aircrew of 'show boating' now reflect and perhaps recognise that amazing act of skill for what it was and admit they were incorrect in their assumptions?
John
I tend to respect folks that when proved to be wrong hold up their hands and apologise!!
Might I respectfully suggest all those that thought the video was fake or accused that aircrew of 'show boating' now reflect and perhaps recognise that amazing act of skill for what it was and admit they were incorrect in their assumptions?
John
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From what I hear not the Flight Engineer on board but a Ground Engineer before the flight. Appears to be a translation/transmittal problem between the reports and the press, who were indicating the FE to be responsible. However, the connections involved point towards maintenance action on the ground and were not accessible (or reversible) by the FE.
http://www.pprune.org/rumours-news/5...ml#post9653471
http://www.pprune.org/rumours-news/5...ml#post9654842
