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Originally Posted by COflyer
(Post 10426080)
Would you need to bump just one TOGA sw, or both?
Originally Posted by Herod
(Post 10426169)
IIRC, on all aircraft I've flown that had TOGA switches, the buttons are inset, to prevent accidental activation. That means a digit has to be inserted into the cup to select TOGA, not just bumping against the switch.
https://i0.wp.com/aerosavvy.com/wp-c...1200.jpg?ssl=1 |
Weird, on the B747 those are the autothrottle disconnect switches...
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Originally Posted by ABusDrivr
(Post 10425322)
Got this info from my airlines unofficial forum. Unofficial of course .
The initial bobble is from turbulence at 6200’. When the FO called for flaps 1, the captain accidentally hit the toga button. Toga didn’t engage until after flaps were set to 1, which then brought engine power to full, and started the initial pitch of 10 degrees nose up. The FO was startled, and shoved the nose forward... The CVR is startling, and baffling. The CA was pulling so hard against the FO that he sheared the pins on the stick and at that point had no control. They were IMC at the time. When they broke out into VMC, the FO said oh schit and started to pull. That was the round out you see. I won’t get into anything more until everything comes out. The records, the CVR, and what happened in the flight deck is truly shocking. They hit a negative 4 G dive initialy on the FOs push. All you hear is stuff hitting the ceiling and at one point a loud thud. They think the thud may have been the JS hitting the ceiling and maybe not wearing the shoulder harness. Like I said, I won’t get into anything more about the background of how it all happened. This is the accident in a nutshell. The facts that will come out are shocking. The info came from an unofficial airline forum Does TOGA command full power? If one control column "pins" are sheared, does that make the other useless? Wasn't this a bit far out to start putting flaps out? Were they actually IMC when this started? Another post said they had the boards up. Would they be calling for flaps with the boards up? Thanks for any comments. OBD Update (per an instructor): TOGA tries to maintain 2K ROC...They were IMC. It is OK to use flaps/boards in some circumstances, and they were close enough to use both in order to expidite descent. Unknown about the column question. |
Originally Posted by ABusDrivr
(Post 10425322)
Got this info from my airlines unofficial forum. Unofficial of course .
The initial bobble is from turbulence at 6200’. When the FO called for flaps 1, the captain accidentally hit the toga button. Toga didn’t engage until after flaps were set to 1, which then brought engine power to full, and started the initial pitch of 10 degrees nose up. The FO was startled, and shoved the nose forward... The CVR is startling, and baffling. The CA was pulling so hard against the FO that he sheared the pins on the stick and at that point had no control. They were IMC at the time. When they broke out into VMC, the FO said oh schit and started to pull. That was the round out you see. I won’t get into anything more until everything comes out. The records, the CVR, and what happened in the flight deck is truly shocking. They hit a negative 4 G dive initialy on the FOs push. All you hear is stuff hitting the ceiling and at one point a loud thud. They think the thud may have been the JS hitting the ceiling and maybe not wearing the shoulder harness. Like I said, I won’t get into anything more about the background of how it all happened. This is the accident in a nutshell. The facts that will come out are shocking. That does not result in what the airplane did. |
Originally Posted by 742
(Post 10426284)
So the stab is trimmed for 240 knots. FO pushes full forward. Captain pulls back and splits the yokes (as designed). So you have a stab trimmed for 240 knots, one elevator full down and one elevator full up. And a lot of power has been added, which of course is "nose up".
That does not result in what the airplane did. Again, this would be the case in older Boeings. Do not know about this one. |
Here is a diagram to show the "Break out" box. When one side overrides the other, control is not lost. Just transferred to the other column. Diagram is from a 737NG
https://cimg5.ibsrv.net/gimg/pprune....fe8be292b0.png |
Originally Posted by 747-8driver
(Post 10426195)
Weird, on the B747 those are the autothrottle disconnect switches...
As to the other discussions: TOGA on Boeing...it is correct that 2000 FPM is commanded on the FIRST push of the TOGA switch...on some Boeing 74/75/76 (customer option) the SECOND push gets you MAX thrust. So the scenario that these were mistakenly pushed once and possibly twice might be a long shot given the system design and physical placement of the TOGA switches. NTSB said MAX thrust was recorded on the FDR. So one push doesn't make sense to me given what we know about the system. |
When one column over rides they other, full control is given to the operable control column. the control surfaces are not split. The Jetstream 4100 has a cockpit release to split the two elevator circuits from each other, so the left control wheel controls the left elevator, and right controls right. In the Dash 8, there is a release in the ailerons, so if one jams, it is released, and split from the other, and the cockpit controls now operate only the free aileron. This is unrelated to control columns being disconnected from each other at the cockpit. Doesn't the "breakout box" depicted for the 737NG, simply allow the two control columns to act independently of each other to control their respective elevator? |
Originally Posted by Old Boeing Driver
(Post 10426291)
When one column over rides they other, full control is given to the operable control column. the control surfaces are not split.
Again, this would be the case in older Boeings. Do not know about this one. |
Here is the 767 diagram. Image is not as clear as the other. It does show there is some type of override between the 2 columns. I think it has something to do with the transducers. The systems are split, left and right, but in the override scenario, the operable one still controls all surfaces.
https://cimg1.ibsrv.net/gimg/pprune....7f89e6e41b.jpg |
Originally Posted by TRey
(Post 10426298)
TOGA on Boeing...it is correct that 2000 FPM is commanded on the FIRST push of the TOGA switch...on some Boeing 74/75/76 (customer option) the SECOND push gets you MAX thrust. So the scenario that these were mistakenly pushed once and possibly twice might be a long shot given the system design and physical placement of the TOGA switches. NTSB said MAX thrust was recorded on the FDR. So one push doesn't make sense to me given what we know about the system.
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Originally Posted by Airbubba
(Post 10426328)
Actually, max thrust is indeed commanded initially with the 767 TOGA switches and then thrust is reduced when a 2000 fpm climb is achieved. So, the thrust will not throttle back if you don't allow the nose to rise and you don't pull back or disarm the autothrottles.
I guess what I’m getting at is how quickly would the thrust and climb be recognized as an inadvertent activation of TOGA. The possible delay between possible switch activation and flaps 1 being configured and the resultant TOGA would make it hard to figure out immediately. |
" When pushing either GA switch:
• autothrottle increases thrust with adjustment, as necessary, to maintain a climb rate of 2000 fpm" FCOM -300ER reference. |
Been a long rime since I've flown the 767.
But this doesn't make sense, the TOGA switches only work when armed. So accidentally pressing them, then selecting flaps 1 would result in nothing happening???? |
I know nothing about the 76, so can't comment on the mechanics of the TOGA switch. But if the above narrative is correct, the physiological factors alone may hampered the recovery. A -4.0 G load is something very few of us have ever experienced or are prepared to be surprised by. It is possible the CA and FO were physically unable to correct the dive once started until the aircraft was established in a more neutral G load. Further, the resulting vision impairment would have in itself been greatly disorienting and may have caused the FO to lose track of his artificial horizon.
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Take that CVR "report" with a big pinch of salt, I remember on the germanwings accident there was a "report" about how on the Cvr they heard the window go and then all rushing air as the plane came apart....
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Originally Posted by Airbubba
(Post 10426328)
Actually, max thrust is indeed commanded initially with the 767 TOGA switches and then thrust is reduced when a 2000 fpm climb is achieved. So, the thrust will not throttle back if you don't allow the nose to rise and you don't pull back or disarm the autothrottles.
Unfortunately I have never witnessed that particular behavior in the 757 or 767 in real life or in the sim world. Often times the power only comes up 1/2 to 2/3 of the G/A thrust limit, depending on weight and other factors. In my experience Boeing has a lot of options on these airplanes so that’s one I haven’t heard yet...or it could be I just don’t pay close enough attention...just ask any FO who flies with me, they’ll tell ya:) |
Just a thought, what if bumping TOGA with F1 was only the cause of the pitch change, and since the PF thought it was going to stall he pushed the yoke forward then gave it max thrust?
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Originally Posted by V1rhot8
(Post 10426592)
Just a thought, what if bumping TOGA with F1 was only the cause of the pitch change, and since the PF thought it was going to stall he pushed the yoke forward then gave it max thrust?
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Complete ignorant here... Would selecting TOGA move the thrust leveler accordingly? |
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