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Atlas Air 3591 NTSB Public Docket Opened

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Atlas Air 3591 NTSB Public Docket Opened

Old 20th Dec 2019, 04:30
  #21 (permalink)  
 
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Wow, things went from perfect day to total loss in just 32 seconds
If I interpret this correctly (and add the Bert Botta quote to the equation), the captain realized what just happened but he couldn't do anything about it (no comms -> shear pin -> no control), and by the time FO got the hang of it, it was inevitably too late.
Actually: based on Bert Botta quote above, there was nothing they could've done anyway at the point captain grabbed the controls, due to lack of altitude.
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Old 20th Dec 2019, 06:02
  #22 (permalink)  
 
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Just a GA pilot here, but if the two yokes were going opposite ways, why does the captains yoke shear pin break and why not the shear pin on the first officer's yoke? Would it not make sense to assume that the captain is most likely more experienced and more apt to be making the proper (or desired) inputs over the first officer (except when training)?

Just as in this case, if the first officer makes an incorrect control movement that requires opposite correction by the captain, would it not make more sense for the system to lock out the first officer's yoke and leave control with the captain?
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Old 20th Dec 2019, 06:35
  #23 (permalink)  
 
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Originally Posted by StudentPilot479 View Post
Just a GA pilot here, but if the two yokes were going opposite ways, why does the captains yoke shear pin break and why not the shear pin on the first officer's yoke? Would it not make sense to assume that the captain is most likely more experienced and more apt to be making the proper (or desired) inputs over the first officer (except when training)?

Just as in this case, if the first officer makes an incorrect control movement that requires opposite correction by the captain, would it not make more sense for the system to lock out the first officer's yoke and leave control with the captain?
No, because the Captain is not always right, and on more than one occasion it was the FO who saved the day. Just imagine an incapacitation of the Captain. Reflecting a command gradient in the controllability of an airplane could easily do more harm than good.
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Old 20th Dec 2019, 06:39
  #24 (permalink)  
 
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To add to that, the Captain is not always more experienced (although, it is a general rule of thumb). In addition, the failure may be on the captain’s side.

Also, occasionally the PIC will be in the right seat.
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Old 20th Dec 2019, 06:42
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Given all that information now, and the fact that the FO had poor training records and washouts at Atlas and also with previous employers, what exactly is the point of the FO‘s family suing Amazon?

There seems to be no indication of any aircraft malfunction, caused by negligence and sloppy maintenance.
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Old 20th Dec 2019, 08:35
  #26 (permalink)  
 
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Wait, why was GA mode activated?
And because of the acceleration perceived as a pitch up the FO pushed the nose down?
Why did the FO think the AC was stalling? Was this before or after the activation of GA?
confused here..
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Old 20th Dec 2019, 08:49
  #27 (permalink)  
 
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Wait, why was GA mode activated? By accident apparently?
And because of the acceleration perceived as a pitch up the FO pushed the nose down? Apparently, yes
Why did the FO think the AC was stalling? Was this before or after the activation of GA? After, based on the combined timeline of CVR transcript and FDR data.

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Old 20th Dec 2019, 09:27
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I’m also confused about the “stall” comment. The maximum pitch recorded after GA was annunciated was 5 deg ANU. His training records, and comments from prior trainers are interesting to read.
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Old 20th Dec 2019, 10:56
  #29 (permalink)  
 
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Originally Posted by Beamr View Post
Wow, things went from perfect day to total loss in just 32 seconds .
Actually I think things were not a perfect day for a while before the loss of control.
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Old 20th Dec 2019, 11:45
  #30 (permalink)  
 
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Originally Posted by bud leon View Post
Actually I think things were not a perfect day for a while before the loss of control.
Of course theres always room for debate on when the events started folding, I am looking at the moment of the unintentional GA command, 32 sec before impact.
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Old 20th Dec 2019, 12:40
  #31 (permalink)  
 
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STOP saying the yoke “shear pin” broke. For the love of god, the system doesn’t have a yoke shear pin, the system has shear rivets at the PCUs that power the elevator, and a force breakout mechanism between the two yokes. Nothing on this airplane broke. The entire control system worked how it was designed. There is a breakout mechanism between the two yokes, not a shear pin. It’s to mitigate a control jam. When a certain amount of opposite force is applied by fo or capt, you get an elevator split.

Additionally, only captains side column position is recorded on this bird. These older cargo planes only have to record 34 parameters. If you want to “see” what the fo was doing with his controls you would have to back it out from the amount of elevator split.

stop repeating this pilot rumor nonsense that a non existent shear pin broke and the jump seater hit the ceiling. None of this is in any of the factual reports released.
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Old 20th Dec 2019, 13:52
  #32 (permalink)  
 
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Originally Posted by StudentPilot479 View Post
Just a GA pilot here, but if the two yokes were going opposite ways, why does the captains yoke shear pin break and why not the shear pin on the first officer's yoke? Would it not make sense to assume that the captain is most likely more experienced and more apt to be making the proper (or desired) inputs over the first officer (except when training)?

Just as in this case, if the first officer makes an incorrect control movement that requires opposite correction by the captain, would it not make more sense for the system to lock out the first officer's yoke and leave control with the captain?
when the shear pin breaks the control columns operate the elevators of there respective sides, so in this instance the FO’s elevator would have been deflected down whist the Capt who was pulling back would have deflected his upwards, once the fo realize what was actually happening he then was able to pull nose up on his!
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Old 20th Dec 2019, 16:38
  #33 (permalink)  
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Originally Posted by StudentPilot479 View Post
Just a GA pilot here, but if the two yokes were going opposite ways, why does the captains yoke shear pin break and why not the shear pin on the first officer's yoke?
Originally Posted by Dogsofwar View Post
when the shear pin breaks the control columns operate the elevators of there respective sides, so in this instance the FO’s elevator would have been deflected down whist the Capt who was pulling back would have deflected his upwards, once the fo realize what was actually happening he then was able to pull nose up on his!
I don't believe there is any shear pin involved in a 767.

From my earlier post on a closed thread:

Here's a description of the B-763 control column operation with one side jammed from page 12 of the MS990 NTSB accident report:
The captains and first officers control columns have authority to command full travel of the elevators under most flight conditions and normally work together as one system. However, the two sides of the system can be commanded independently because of override mechanisms at the control columns and aft quadrant. Therefore, if one side of the system becomes immobilized, control column inputs on the operational side can cause full travel of the nonfailed elevator. In addition, in many cases, control column inputs on the operational side can also result in nearly full travel of the elevator on the failed side through the override mechanisms. The elevator PCAs are installed with compressible links located between each bellcrank assembly and PCA input control rod to provide a means of isolating a jammed PCA, thus allowing the pilots to retain control of that elevator surface through its two remaining (unjammed) PCAs




From the Performance Report in the recently released docket:

Figure 7 shows an elevator split between the left and right sides of the airplane: the left elevator is associated with the captain in the left seat, and the right elevator is associated with the first officer in the right seat. The elevator deflections are similar until about 1238:46. At that time, the first officer is heard asking a question about airspeed on the CVR, and the elevators begin to split: the captain begins to pull from 2˚ to 8˚ more ANU elevator than the first officer. The split continues until about 1238:56, about one second after the airplane would have broken out of the reported 3,500 ft cloud layer. Both the captain and the first officer subsequently commanded ANU elevator until impact. (The normal load factor recorded by the FDR in Figure 6 is greater than 4g right before impact.)
There was an earlier rumor of a -4g load factor on the pitchover, this was apparently a typo (or an exaggeration).
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Old 20th Dec 2019, 17:11
  #34 (permalink)  
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An article from Air Cargo News:

Atlas 767 crash: Go-around mode activated after mystery ‘click’

20 / 12 / 2019
By David Kaminski-Morrow - Flight Global

Investigators probing the fatal Atlas Air Boeing 767-300 freighter crash near Houston have been trying to ascertain whether a sound captured on the cockpit-voice recorder signifies the activation of the go-around switch immediately before the accident sequence.

The aircraft, which was flying on behalf of Amazon Air, suddenly entered a steep nose-down attitude and dived into Trinity Bay from around 6,000ft while preparing for an approach to Houston on February 23.

National Transportation Safety Board investigators have released detailed information on the cockpit-voice and flight-data recordings, as well as a spectral analysis of certain sounds in the cockpit.

Cockpit conversation indicates that the flight was progressing normally, with a call to start extending the flaps heard some 60s before the impact.

But just under 30s after this “flaps 1” call, and shortly after the jet encountered moderate turbulence, the recorder picks up the sound of a click, the origin of which has been of particular interest to the inquiry.

The time alignment of the click, it says, matched flight-data recorder information showing activation of the go-around mode.

Spectral analysis has been conducted to try to establish the likely source of the sound. Although the recording quality was poor, investigators have used filtering and detailed comparison with the double-click of a 767 go-around button being pushed and released to try to identify the noise.

The inquiry says the mysterious click on the cockpit recorder “shares a similar characteristic” to the go-around button activation, and that it “could potentially be associated” with the release portion of the double-click.

“However, it cannot be conclusively determined if it is the same sound due to the degraded quality of the [recording] at the time of the sound detection,” it stated.

Accompanying documentation, however, suggests the inquiry is convinced that a go-around switch on the throttle levers was triggered. The accident sequence developed rapidly afterwards.

Simultaneously with the click, the autoflight system entered go-around mode – which had been armed when the flaps were deployed – and the engine thrust began advancing to the go-around setting.

Flight-data recorder information shows the aircraft started pitching up and entered a shallow climb.

The 767’s control column moved to a forward deflection, with the pitch decreasing and the aircraft accelerating rapidly from 240kt.

Caution alarms began to sound, just 9s after the go-around mode engaged. The inquiry says the control column remained deflected forward for 10s and the aircraft transitioned from a shallow climb to a steep descent.

Five seconds after the alarm commenced, one of the pilots exclaimed, “Whoa”, and shortly afterwards, in an elevated voice: “Where’s my speed, my speed”. Three seconds later, a voice loudly declared: “We’re stalling.”

Flight-data recordings reveal that, during these remarks, the thrust levers were brought to idle for about 2s and then were advanced again to their previous power setting. The aircraft’s pitch rapidly declined and the jet experienced negative g-forces for nearly 11s.

Investigators have disclosed that the recording shows the right and left elevators were split – by 2° to 7° – for some 10s beginning around the point of the “we’re stalling” remark.

The aircraft continued to dive through 2,000ft altitude at which point the flight-data recorder showed the control column being moved full aft until the end of the recording.

Although pitch recovered from 50° nose-down to 16° nose-down, the dive could not be arrested in time and the aircraft struck the water at over 430kt. None of the three occupants survived.

Investigators have yet to draw conclusions over the circumstances and contributing factors to the accident.

Meanwhile, Atlas Air and Amazon.com Services are among the companies named in a lawsuit filed by the brother of one of the pilots, Elliott Aska, killed in the tragic B767 freighter accident earlier this year.
https://www.aircargonews.net/airline...mystery-click/
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Old 20th Dec 2019, 17:49
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With a sudden acceleration and small pitch up from TOGA, could that create illusion of a stall?
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Old 20th Dec 2019, 18:09
  #36 (permalink)  
 
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Originally Posted by Joejosh999 View Post
With a sudden acceleration and small pitch up from TOGA, could that create illusion of a stall?
It might well lead to the sensation of a steep climb (cf. somatogravic illusion) but I don’t see how that sensation, in isolation, could lead a competent pilot to think the aircraft might be in a stall...



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Old 20th Dec 2019, 18:37
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Yeah. Also he was unsure of speed.
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Old 20th Dec 2019, 19:33
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Originally Posted by Joejosh999 View Post
With a sudden acceleration and small pitch up from TOGA, could that create illusion of a stall?
Here's a discussion of a possible pitch illusion from the Airplane Performance Study posted above. I agree with wiggy, I'm not sure that would cause 'a competent pilot' to think the plane was in a stall. The Gulf Air 72 crash in Y2K sounds like a similar pitch over into the water after a sudden longitudinal acceleration as TOGA thrust was selected.



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Old 20th Dec 2019, 19:35
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Originally Posted by dcoded View Post
Why did the FO think the AC was stalling? Was this before or after the activation of GA?
confused here..
Probably because he pushed zero or negative g. In the gliding world, they do a lot of training on the difference between zero g and a stall, but that is not always so in power flying. Zero g can be disorientating, if you have not felt it (and it cannot be simulated in a sim), and ab-initios can often react to zero g by pushing harder.

I liken this to AA587, where excessive rudder inputs were used, resulting in the vertical stabiliser tearing off. In a swept wing aircraft, an agg.ressive rudder input will result in a sharp roll, which could be mistaken for a stall and wing-drop. And the cure for a wing drp stall, is an agg,ressive opposite rudder input, which simply drops the other wing. And so you get a rudder-reversal, because of another misperception of a stall.

And AF447 is not dissimilar to these two incidents. And all caused by first officers, who seem to lack basic training in light aircraft.

It seems clear to me that ALL first officers should complete a two week gliding course, perhaps after their first year of commercial flying, where they can learn basic stick and rudder skills, and to correctly identify a stall and instinctively react to it. In the 21st century, we should not have first officers who...

Think that zero g at high speed is a stall.
Think that a wing drop at high speed is a stall.
Think that pulling 20 degrees of pitch at 35,000 ft is NOT a stall.

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Old 20th Dec 2019, 19:52
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Wasn’t 447 FO a glider pilot? Perhaps I mis-remember?...
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