Boeing 767 crash near Houston, TX

Isn't there something like a runaway trim tab? A friend that flies Gulfstreams and Citations once told me the examiners give them that situation in the simulators. He's not a frail guy and says almost max physical force is needed to correct attitude until the situation is recognized and the trim system turned off.
 
Originally Posted by Astro14
Originally Posted by john_pifer
https://www.ntsb.gov/investigations...CpOsQnij-bBxcql4Ds9u-DuhETTZdo_OuBQM7lLY


Thanks - more information, but still too early to tell anything.

I can't answer the question of "was this yoke input from pilot or autopilot?".

Not enough is yet known.


I would think part of the black box data is recording if autopilot is turned on or off. Even if the plane is in autopilot, the controls can be manipulated real time by the pilot. If the controls were done by a human then it leads the investigation down a different path.
 
With full runaway trim, the 767-300 can be flown. It takes about 75 lbs of yoke pressure. Not easy. But fly able...

There are trim cutout switches (same trim cutout switches that allow the 737 MAX MCAS system to be cut out) on the Captain's side of the pedestal. Designed to cut out both trim motors and stop a runaway. If the pilot flying fails to recognize the runaway, then yeah, it's a handful.

But still completely flyable.
 
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Originally Posted by ZeeOSix
Originally Posted by Astro14
Originally Posted by john_pifer
https://www.ntsb.gov/investigations...CpOsQnij-bBxcql4Ds9u-DuhETTZdo_OuBQM7lLY


Thanks - more information, but still too early to tell anything.

I can't answer the question of "was this yoke input from pilot or autopilot?".

Not enough is yet known.


I would think part of the black box data is recording if autopilot is turned on or off. Even if the plane is in autopilot, the controls can be manipulated real time by the pilot. If the controls were done by a human then it leads the investigation down a different path.


It would lead them down a different path.

To date, nothing leads to deliberate crash.

And nothing rules it out, either.

If the NTSB knows, or suspects, they're not sharing.

Not yet.

A split yoke, ala EgyptAir 990, would be extraordinarily revealing...
 
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The jump seater on this flight was named Sean Archuleta.

He was due to start as a new hire at United Airlines last week.

On her flight to Houston, the day after the crash, his wife was presented a set of United pilot wings and a captains hat by the captain of that flight.

When his class started in Denver, United remembered him. Much like the table for POW/MIA at a military dining event.

The go fund me for his family has exceeded $200,000, largely funded by United Pilots.

[Linked Image]
 
Originally Posted by Astro14
Originally Posted by ZeeOSix
Originally Posted by Astro14
Originally Posted by john_pifer
https://www.ntsb.gov/investigations...CpOsQnij-bBxcql4Ds9u-DuhETTZdo_OuBQM7lLY


Thanks - more information, but still too early to tell anything.

I can't answer the question of "was this yoke input from pilot or autopilot?".

Not enough is yet known.


I would think part of the black box data is recording if autopilot is turned on or off. Even if the plane is in autopilot, the controls can be manipulated real time by the pilot. If the controls were done by a human then it leads the investigation down a different path.


It would lead them down a different path.

To date, nothing leads to deliberate crash.

And nothing rules it out, either.

If the NTSB knows, or suspects, they're not sharing.

Not yet.

A split yoke, ala EgyptAir 990, would be extraordinarily revealing...


Astro -

You mention a "split yoke" condition. In the Wiki article for EgyptAir 990, it's mentioned that, in the 767, one elevator up and one down can happen from having at least 50 lbs of differential force applied to each control column. In other words, one pilot was attempting to dive, and the other, to climb, and each was pulling or pushing on his respective column with quite a bit of force.

This brings up a question: The Embraer airliners have a roll control disconnect, as well as a pitch control disconnect, allowing independent operation of the control yoke or control column in case one side of either gets jammed.

The disconnect discs are mounted on the aileron torque tube and the elevator torque tube, underneath the floor, and allow for the pilot and co-pilot control column or yoke to operate in sync, unless one of the disconnect handles on the console is pulled, in which case roll or pitch control is possible by whichever side is not jammed.

I'm sure the Boeing and Airbus aircraft have similar systems.

I've never thought about this before, but your comment on "split yoke condition" got me wondering. What would happen if, during a flight, neither the column nor the yoke was jammed, but the disconnect handles were pulled? Who would have roll and pitch control? The pilot or the co-pilot? Once disconnected, the disconnect discs must be re-connected on the ground. There would be no way to reconnect them in flight.

I've disconnected and removed these discs many times in order to disassemble, lubricate, test them on the bench and re-install, but it's never occurred to me to check flight control operation when they're out.

(Well, the removal procedure calls for installation of rig pins in the control column or control yoke torque tubes in order to prevent any relative movement while the disconnect discs are out, so, by following the manual, we would not be able to perform such a test.)
 
John, I'm out in the garage and don't have my flight manual.

My understanding of the yoke system in the Boeing is that in the event of excess force, I thought it was 75, but perhaps it's 50 pounds.

There is no manual disconnect, it's a matter of force.

Once the yokes are split, the right yoke controls right elevator, the left yoke controls the left, if memory serves.

That was a key piece of evidence in Egypt Air 990. The FO was trying to force the airplane down, the Captain trying to pull it up. Then someone shut off the eungines using the fuel control switches. I accept the NTSB conclusion, pilot suicide, as the best explanation.

Naturally, that was not popular in Egypt, and their aviation authorities concluded that the Boeing 767 was of faulty design...

Sure, pretty faulty to build an airplane that won't fly when the engines are deliberately shut off by the crew...

I'm fascinated by all the pundits, "journalists" and "experts" who call for airplanes to over-ride pilots after accidents like that one...

Because they're the same ones who are shocked that an airplane could over-ride pilots in this crash...
 
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I remember that. Particularly how Egypt claimed a person of "a particular following" would never commit suicide by crashing an airplane and killing a bunch of innocent people. That argument isn't in use anymore.
 
Originally Posted by john_pifer
https://www.ntsb.gov/investigations...CpOsQnij-bBxcql4Ds9u-DuhETTZdo_OuBQM7lLY


From the NTSB's update I would have to conjecture that it was a windshear situation. Apparently the TDWR was operational since ATC had been giving terminal weather updates to the the crew.

My last major aerospace project was with an avionics company developing Predictive Wind Shear (PWS) radar. Our group had to get cranked up on Meterology and especially the physics of wind shear and the detection thereof.

One of the first papers we read was Marylin Wolfson's paper on, "Characteristics of Microbursts in the
Continental United States" and the many NACAR and NASA research papers. A facinating project to say the least.
cool.gif
 
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Originally Posted by MolaKule
Originally Posted by john_pifer
https://www.ntsb.gov/investigations...CpOsQnij-bBxcql4Ds9u-DuhETTZdo_OuBQM7lLY


From the NTSB's update I would have to conjecture that it was a windshear situation. Apparently the TDWR was operational since ATC had been giving terminal weather updates to the the crew.

My last major aerospace project was with an avionics company developing Predictive Wind Shear (PWS) radar. Our group had to get cranked up on Meterology and especially the physics of wind shear and the detection thereof.

One of the first papers we read was Marylin Wolfson's paper on, "Characteristics of Microbursts in the
Continental United States" and the many NACAR and NASA research papers. A facinating project to say the least.
cool.gif



OK, but what about the fact that the control column was pushed all the way forward, and the throttles went balls to the wall for the last 18 seconds before impact?

Also, the report says the stick shaker never activated.
 
Originally Posted by john_pifer
Originally Posted by MolaKule
Originally Posted by john_pifer
https://www.ntsb.gov/investigations...CpOsQnij-bBxcql4Ds9u-DuhETTZdo_OuBQM7lLY


From the NTSB's update I would have to conjecture that it was a windshear situation. Apparently the TDWR was operational since ATC had been giving terminal weather updates to the the crew.

My last major aerospace project was with an avionics company developing Predictive Wind Shear (PWS) radar. Our group had to get cranked up on Meterology and especially the physics of wind shear and the detection thereof.

One of the first papers we read was Marylin Wolfson's paper on, "Characteristics of Microbursts in the
Continental United States" and the many NACAR and NASA research papers. A facinating project to say the least.
cool.gif



OK, but what about the fact that the control column was pushed all the way forward, and the throttles went balls to the wall for the last 18 seconds before impact?

Also, the report says the stick shaker never activated.


Windshear. Pilot suicide. Flight control malfunction.

All pure speculation, and the leaks from the NTSB are irresponsible at best.

By the time the real story is known, people won't care, and all they will remember is the speculation, repeated over endless news cycles, "Oh yeah, that was the one that the Navy shot down, right?"

I'm not certain that "control column pushed all the way forward and the throttles went balls to the wall" is a fact. Preliminary, I repeat, preliminary data shows full power. But it hasn't been confirmed.

If the throttles were balls to the wall for 18 seconds, and the airplane was in a dive, that is difficult to understand, but there are a variety of explanations, all of which remain speculation. Here is an interesting bit of human physiology, however: when you feel longitudinal acceleration, it feels like you are pitching up. So, cat shot at night. Full thrust acceleration in IMC. Your inner ear is lying, big time, and tells you that the nose is coming up. You cannot rely on that feeling, or you will push the nose down farther and farther as the acceleration happens. You MUST rely on instruments. This killed a friend of mine, long ago, on a night cat shot with no horizon. In IMC, with no visual reference, it is just as strong an illusion and just as deadly...

Somatogravic illusion
 
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Originally Posted by john_pifer
Originally Posted by MolaKule
Originally Posted by john_pifer
https://www.ntsb.gov/investigations...CpOsQnij-bBxcql4Ds9u-DuhETTZdo_OuBQM7lLY


From the NTSB's update I would have to conjecture that it was a windshear situation. Apparently the TDWR was operational since ATC had been giving terminal weather updates to the the crew.

My last major aerospace project was with an avionics company developing Predictive Wind Shear (PWS) radar. Our group had to get cranked up on Meterology and especially the physics of wind shear and the detection thereof.

One of the first papers we read was Marylin Wolfson's paper on, "Characteristics of Microbursts in the
Continental United States" and the many NACAR and NASA research papers. A facinating project to say the least.
cool.gif



OK, but what about the fact that the control column was pushed all the way forward, and the throttles went balls to the wall for the last 18 seconds before impact?

Also, the report says the stick shaker never activated.



Originally Posted by MolaKule
From the NTSB's update I would have to conjecture that it was a windshear situation. Apparently the TDWR was operational since ATC had been giving terminal weather updates to the the crew.

Anyone can submit an educated guess or conjecture at this point in time but it is still conjecture.
 
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Originally Posted by Astro14
Originally Posted by john_pifer
Originally Posted by MolaKule
Originally Posted by john_pifer
https://www.ntsb.gov/investigations...CpOsQnij-bBxcql4Ds9u-DuhETTZdo_OuBQM7lLY


From the NTSB's update I would have to conjecture that it was a windshear situation. Apparently the TDWR was operational since ATC had been giving terminal weather updates to the the crew.

My last major aerospace project was with an avionics company developing Predictive Wind Shear (PWS) radar. Our group had to get cranked up on Meterology and especially the physics of wind shear and the detection thereof.

One of the first papers we read was Marylin Wolfson's paper on, "Characteristics of Microbursts in the
Continental United States" and the many NACAR and NASA research papers. A facinating project to say the least.
cool.gif



OK, but what about the fact that the control column was pushed all the way forward, and the throttles went balls to the wall for the last 18 seconds before impact?

Also, the report says the stick shaker never activated.


Windshear. Pilot suicide. Flight control malfunction.

All pure speculation, and the leaks from the NTSB are irresponsible at best.

By the time the real story is known, people won't care, and all they will remember is the speculation, repeated over endless news cycles, "Oh yeah, that was the one that the Navy shot down, right?"

I'm not certain that "control column pushed all the way forward and the throttles went balls to the wall" is a fact. Preliminary, I repeat, preliminary data shows full power. But it hasn't been confirmed.

If the throttles were balls to the wall for 18 seconds, and the airplane was in a dive, that is difficult to understand, but there are a variety of explanations, all of which remain speculation. Here is an interesting bit of human physiology, however: when you feel longitudinal acceleration, it feels like you are pitching up. So, cat shot at night. Full thrust acceleration in IMC. Your inner ear is lying, big time, and tells you that the nose is coming up. You cannot rely on that feeling, or you will push the nose down farther and farther as the acceleration happens. You MUST rely on instruments. This killed a friend of mine, long ago, on a night cat shot with no horizon. In IMC, with no visual reference, it is just as strong an illusion and just as deadly...

Somatogravic illusion





I was very surprised when I heard the NTSB had already released the report.
 
Originally Posted by Astro14
Originally Posted by john_pifer
Originally Posted by MolaKule
Originally Posted by john_pifer
https://www.ntsb.gov/investigations...CpOsQnij-bBxcql4Ds9u-DuhETTZdo_OuBQM7lLY


From the NTSB's update I would have to conjecture that it was a windshear situation. Apparently the TDWR was operational since ATC had been giving terminal weather updates to the the crew.

My last major aerospace project was with an avionics company developing Predictive Wind Shear (PWS) radar. Our group had to get cranked up on Meterology and especially the physics of wind shear and the detection thereof.

One of the first papers we read was Marylin Wolfson's paper on, "Characteristics of Microbursts in the
Continental United States" and the many NACAR and NASA research papers. A facinating project to say the least.
cool.gif



OK, but what about the fact that the control column was pushed all the way forward, and the throttles went balls to the wall for the last 18 seconds before impact?

Also, the report says the stick shaker never activated.


Windshear. Pilot suicide. Flight control malfunction.

All pure speculation, and the leaks from the NTSB are irresponsible at best.

By the time the real story is known, people won't care, and all they will remember is the speculation, repeated over endless news cycles, "Oh yeah, that was the one that the Navy shot down, right?"

I'm not certain that "control column pushed all the way forward and the throttles went balls to the wall" is a fact. Preliminary, I repeat, preliminary data shows full power. But it hasn't been confirmed.

If the throttles were balls to the wall for 18 seconds, and the airplane was in a dive, that is difficult to understand, but there are a variety of explanations, all of which remain speculation. Here is an interesting bit of human physiology, however: when you feel longitudinal acceleration, it feels like you are pitching up. So, cat shot at night. Full thrust acceleration in IMC. Your inner ear is lying, big time, and tells you that the nose is coming up. You cannot rely on that feeling, or you will push the nose down farther and farther as the acceleration happens. You MUST rely on instruments. This killed a friend of mine, long ago, on a night cat shot with no horizon. In IMC, with no visual reference, it is just as strong an illusion and just as deadly...

Somatogravic illusion


This crash happened during daylight, so the pilots would have had some visual attitude reference. Obviously at night with no visual reference of the horizon your senses can be distorted and you need to trust the flight instrumentation.
 
For fun read about the plane crashes in the great lakes triangle. Many many cases of nose diving into the ground. And some with the trim all the way nose up.
Sounds like a loss of atmosphere. Oh and don't forget the incidents of birds just falling from the sky as well.
 
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Latest speculation on the Atlas Air 3591 crash. Apparently there's speculation on the web that one of the pilots inadvertently pressed one of the TOGA switches, resulting (naturally) in a pitch-up, and that the other pilot reacted by pushing the column forward. But, to get into a 49° nose-down dive, he would have had to really shove the nose over violently, I'm thinking.

Apparently this speculation also gets into the possibility of the separation of the disconnect device between the LH and RH control columns due to differential input forces. But, I'm not sure what effect that would really have, if, like rumor has it, the initial dive was the result of violent overreaction by one of the pilots. Let's say he did violently overcorrect. Both pilots would then be pulling back on the column in an attempt to pull out of the resultant dive.

Now, before everybody starts hollering, speculation, conjecture, etc, yes, this is speculation. Of course we won't have a better idea of what really happened until the CVR transcript is released, more details come out from the NTSB report, etc. But, I don't think there's anything wrong with speculating as long as we keep in mind that it is only speculation at this point.
 
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