dragon6172
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 2:31 pm

I'm interested in the reasons for the max thrust? Particularly if you believe the Greg Feith assertion that the AP/AT was coupled through the entire accident sequence.
Phrogs Phorever
 
kalvado
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 2:47 pm

Is it just me, or pushing throttles and column forward can be due to pilot being pushing forward? Seat or seat attachment giving way in turbulence and pilot collapsing forward, or overhead panel falling on the head, or whatever else could be there?
 
asdf
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 2:53 pm

kalvado wrote:
Is it just me, or pushing throttles and column forward can be due to pilot being pushing forward? Seat or seat attachment giving way in turbulence and pilot collapsing forward, or overhead panel falling on the head, or whatever else could be there?


they dont say the collum was pushed forward
they say the actuators have moved

a faulty flight automation can do that
Last edited by asdf on Wed Mar 13, 2019 2:54 pm, edited 1 time in total.
 
TTailedTiger
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 2:54 pm

ALERT wrote:
I will probably be burned for being insensitive here but it seems like there is alot of mental gymnastics trying to explain how this could have happened with spatial disorientation, not understanding how automation is affecting something and reacting incorrectly etc., and everyone is trying to avoid talking about or rule out suicide due to the cvr ( and im not declaring this happened or denying the possibility of other causes) but it really could simply be that the pilot flying decided he was done and nosed it over. Possibly the other pilots weren’t paying attention ( long day, not their leg) and gave him is opportunity. This can often be a spontaneous act without a declaration. The cvr is easily explainable if the person didn’t want it declared suicide ( insurance). Make a vague statement about control issues and point the plane to the ground. No time for anyone to react and 18 seconds later its over.
I don’t like it but it really is occums razor


Yes, an intentional act is still a possibility.
 
OldB747Driver
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 2:58 pm

ALERT wrote:
...it seems like there is alot of mental gymnastics trying to explain how this could have happened with spatial disorientation, not understanding how automation is affecting something and reacting incorrectly etc., and everyone is trying to avoid talking about or rule out suicide due to the cvr ( and im not declaring this happened or denying the possibility of other causes) but it really could simply be that the pilot flying decided he was done and nosed it over. Possibly the other pilots weren’t paying attention ( long day, not their leg) and gave him is opportunity. This can often be a spontaneous act without a declaration. The cvr is easily explainable if the person didn’t want it declared suicide ( insurance). Make a vague statement about control issues and point the plane to the ground. No time for anyone to react and 18 seconds later its over.
I don’t like it but it really is occums razor


It is understandable that folks would suspect intentionality to what seems to be improbable, if not impossible, but those of us who have done this for many, many years can appreciate both the situation and the mentality of the pilots in this situation; given both the wording of the initial NTSB CVR analysis ("crew communication consistent with loss of control") and the flight profile.

Spatial disorientation happens, but at this level, it would be reasonable to suspect at least ONE of the pilots would react correctly or at least make enough of a verbal statement that the other crewmember would be amendable to their disorientation - that is part of the fundamental training at this level of flying / CRM. Thus, incapacitating disorientation is highly unlikely.

As far as intentionality ("he was done and nosed it over") disregards the two other pilots who would not be having a conversation "consistent with loss of control", but a conversation consistent with "WTF are you doing?!?" Adding to this, this crew was in the middle of weather avoidance and rapidly changing maneuvers - likely NONE of this would have occurred if one pilot had nefarious intent. Thus, this too is not very likely. Possible but not likely.

IMHO, the level-off at 6200 with slight climb to 6300 before the nose-over began is the initiating event - an unintended command to the autothrottles resulted in max thrust; the thrust line is below the CG, thus the thrust increase caused the slight pitch up, which the autopilot reacted to with a rapid pitch down to counteract and continue the descent. Something malfunctioned right then and there, and I'm pretty sure it wasn't a pilot. Now could a pilot have caused the error? Thats possible, maybe even likely, but something mechanical (autopilot, elevator, etc) complicated the scenario exponentially.
 
OldB747Driver
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:02 pm

GalaxyFlyer wrote:
IF the excursion started in a trimmed condition,230-ish knots, how could the plane reached 430 knots without some pretty high Gs pulling the nose up unless the autopilot was furiously trimming to keep up with the speed increase?


Gf


An elevator "hardover" fits that explanation quite accurately, no stab trim necessary.
 
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SomebodyInTLS
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:09 pm

ALERT wrote:
everyone is trying to avoid talking about or rule out suicide due to the cvr ( and im not declaring this happened or denying the possibility of other causes) but it really could simply be that the pilot flying decided he was done and nosed it over.


Oh good grief, not this nonsense yet again. (You are FAR from the first person to suggest it - it's the foregone conclusion for many people after every single incident these days)

I don’t like it but it really is occums razor


No, it really is not. There have been TWO, count them, TWO conclusive cases of pilot suicide... EVER!

It is utterly irresponsible to suggest suicide or other foul play without good reason to think so since the statistics clearly show that it almost never happens outside of movies.

To accuse people who are dead and cannot defend themselves of criminal activity that they are very likely NOT to have taken is insulting to them and their families. And it draws attention away from the actual investigation.
Last edited by SomebodyInTLS on Wed Mar 13, 2019 3:15 pm, edited 2 times in total.
"As with most things related to aircraft design, it's all about the trade-offs and much more nuanced than A.net likes to make out."
 
OldB747Driver
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:10 pm

dragon6172 wrote:
I believe the feature you are describing only prevents stab movement opposite control column deflection. If the pilots were pulling back on the control column, the stab trim would still operate in the acft nose up direction, but would be prevented from moving in the acft nose down direction.


I agree, dragon - I'm just trying to figure out what may have kept the crew from trimming that horizontal stab waaaaaay back nose up....
 
Whiplash6
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:12 pm

OldB747Driver wrote:
ALERT wrote:
...it seems like there is alot of mental gymnastics trying to explain how this could have happened with spatial disorientation, not understanding how automation is affecting something and reacting incorrectly etc., and everyone is trying to avoid talking about or rule out suicide due to the cvr ( and im not declaring this happened or denying the possibility of other causes) but it really could simply be that the pilot flying decided he was done and nosed it over. Possibly the other pilots weren’t paying attention ( long day, not their leg) and gave him is opportunity. This can often be a spontaneous act without a declaration. The cvr is easily explainable if the person didn’t want it declared suicide ( insurance). Make a vague statement about control issues and point the plane to the ground. No time for anyone to react and 18 seconds later its over.
I don’t like it but it really is occums razor


It is understandable that folks would suspect intentionality to what seems to be improbable, if not impossible, but those of us who have done this for many, many years can appreciate both the situation and the mentality of the pilots in this situation; given both the wording of the initial NTSB CVR analysis ("crew communication consistent with loss of control") and the flight profile.

Spatial disorientation happens, but at this level, it would be reasonable to suspect at least ONE of the pilots would react correctly or at least make enough of a verbal statement that the other crewmember would be amendable to their disorientation - that is part of the fundamental training at this level of flying / CRM. Thus, incapacitating disorientation is highly unlikely.

As far as intentionality ("he was done and nosed it over") disregards the two other pilots who would not be having a conversation "consistent with loss of control", but a conversation consistent with "WTF are you doing?!?" Adding to this, this crew was in the middle of weather avoidance and rapidly changing maneuvers - likely NONE of this would have occurred if one pilot had nefarious intent. Thus, this too is not very likely. Possible but not likely.

IMHO, the level-off at 6200 with slight climb to 6300 before the nose-over began is the initiating event - an unintended command to the autothrottles resulted in max thrust; the thrust line is below the CG, thus the thrust increase caused the slight pitch up, which the autopilot reacted to with a rapid pitch down to counteract and continue the descent. Something malfunctioned right then and there, and I'm pretty sure it wasn't a pilot. Now could a pilot have caused the error? Thats possible, maybe even likely, but something mechanical (autopilot, elevator, etc) complicated the scenario exponentially.


It’s difficult to explain 49 degrees of pitch down. That’s way outside the peramters of the autopilot.
 
jetmatt777
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:13 pm

OldB747Driver wrote:
dragon6172 wrote:
I believe the feature you are describing only prevents stab movement opposite control column deflection. If the pilots were pulling back on the control column, the stab trim would still operate in the acft nose up direction, but would be prevented from moving in the acft nose down direction.


I agree, dragon - I'm just trying to figure out what may have kept the crew from trimming that horizontal stab waaaaaay back nose up....


Time?

18s from the start of the event isn’t a lot of time. Add in 5 seconds to even recognize an event is even happening and it really shortens the amount of time to correct.
Lighten up while you still can, don't even try to understand, just find a place to make your stand and take it easy
 
OldB747Driver
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:20 pm

Yakflyer wrote:
One thing that I think is lost is just how disorienting the whole event would have been. 18 seconds is not very long and getting the nose down to 49 degrees nose down would have taken IMHO at least 3 or 4 seconds...maybe more. I don't have the engineering to know just how severe what I'm about to say would have been, but I would think there would have been significant negative Gs while the 767 was pitching over. These guys while trying to sort things out were likely "hanging in their belts" even though right side up. And I would think experiencing a lot more than just weightlessness.


I couldn't agree more - when "stuff" happens in a jet, it happens quickly. Almost every emergency training scenario teaches you NOT to jump to conclusions and THINK through the problem - the emergencies that require "Immediate and Timely" action are rehearsed to enable quick action requiring trained memory rather than contemplative deliberation.

I doubt there is a Memory Item titled "Rapid Nose-Over and Uncommanded Autothrottles to Max Thrust".
 
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scbriml
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:24 pm

Whiplash6 wrote:
It’s difficult to explain 49 degrees of pitch down. That’s way outside the peramters of the autopilot.


Which makes it equally difficult to understand the view that the crew "were fighting automation to the end".
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ikramerica
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:24 pm

jetmatt777 wrote:
OldB747Driver wrote:
dragon6172 wrote:
I believe the feature you are describing only prevents stab movement opposite control column deflection. If the pilots were pulling back on the control column, the stab trim would still operate in the acft nose up direction, but would be prevented from moving in the acft nose down direction.


I agree, dragon - I'm just trying to figure out what may have kept the crew from trimming that horizontal stab waaaaaay back nose up....


Time?

18s from the start of the event isn’t a lot of time. Add in 5 seconds to even recognize an event is even happening and it really shortens the amount of time to correct.

Then there is the fact that you can’t be 5 feet from the ground to recover.

The crew did not have enough time after they started severely nose down to recover no matter what.
Of all the things to worry about... the Wookie has no pants.
 
OldB747Driver
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:25 pm

Whiplash6 wrote:
It’s difficult to explain 49 degrees of pitch down. That’s way outside the peramters of the autopilot.


I think most of us who understand these systems here would agree, which is what leads me back to a PCU hardover on one side of the elevator. It seems to fit all the information, at least in my mind.
 
OldB747Driver
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:33 pm

scbriml wrote:
Which makes it equally difficult to understand the view that the crew "were fighting automation to the end".


In my version of what may have possibly occurred, a elevator hardover on one side of the elevator would effect both sides of the elevator initially causing the rapid pitch-down; the natural reactions of the crew would then cause the functional side of the elevator to counteract the pitch-down, thus the aircraft is pitched at 49 degrees nose down but not increasing. As the airspeed increased, according to Boeing's research, the hardover side of the elevator would "blowdown", thus reducing the nose-down tendency in combination with the continued efforts of the crew to pull out of the dive, which would explain the gradually shallowing dive, but not enough authority to complete the maneuver successfully.

Maybe?

[Edit: I think this may have been what Feith meant - that the crew was trying to pull out of the dive without using or unable to use the trim system, which may have saved the day]
Last edited by OldB747Driver on Wed Mar 13, 2019 3:36 pm, edited 1 time in total.
 
Whiplash6
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:34 pm

OldB747Driver wrote:
Whiplash6 wrote:
It’s difficult to explain 49 degrees of pitch down. That’s way outside the peramters of the autopilot.


I think most of us who understand these systems here would agree, which is what leads me back to a PCU hardover on one side of the elevator. It seems to fit all the information, at least in my mind.

It’s plausible, I just find a scenario that requires maximum thrust being followed immediately by a elevator hardover an extremely improbable situation. Like 1 out of a million kind of odds. Max thrust is almost never used unless requested by maintenance for a max thrust takeoff. And those situations are very seldom. It would be more likely that unreliable airspeed was deceiving the crew into believing that the airplane was decreasing in speed instead of increasing. But even that situation is unlikely given the absurd amount of pitch down.
 
trnswrld
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:48 pm

asdf wrote:
they dont say the collum was pushed forward
they say the actuators have moved


They did originally. It was revised at some point, but at first it clearly stated the aircraft was responding the control column inputs.
 
OldB747Driver
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 3:50 pm

Whiplash - even though the Egypt Air 990 was definitely NOT a mechanical malfunction, Boeing had to go to great lengths to describe the elevator control system in that accident report. In a section titled "Potential Causes for Elevator Movements During the Accident Sequence", there are these snippets:
...the failure modes and effects analyses showed that the following four
elevator failure scenarios (each of which involves two failures) warranted further study
because they could potentially cause nose-down elevator movements or a split elevator
condition...

1. Disconnection of the input linkages to two of the three PCAs on the right
elevator surface.
...
For further evaluation, the Systems Group conducted ground tests on an
instrumented 767 to record the elevator system’s response to each of these failure
scenarios.
...
1. Disconnection of the input linkages to two of the three PCAs on the right
elevator surface:

During the ground tests, the failed elevator surface was driven to its full nose-down position and would not respond to nose-up flight control inputs from either control column. A study of the elevator control system indicated that if this scenario occurred in flight, it would result in an initial deflection of the failed surface to a position consistent with a single functioning elevator PCA operating at 100 percent of its maximum force (as limited by aerodynamic blowdown forces); the failed elevator surface would resist being backdriven with a force equivalent to about 130 percent of a single functioning
PCA. Calculations showed that at 280 knots (the accident airplane's airspeed when the initial descent began), this position would initially have been about 6º nose-down elevator deflection, and the degree of deflection would be reduced as the airplane's speed increased above 290 knots.


If interested, I would highly recommend reading starting at page 40.
 
OldB747Driver
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 4:07 pm

jetmatt777 wrote:
OldB747Driver wrote:
I'm just trying to figure out what may have kept the crew from trimming that horizontal stab waaaaaay back nose up....


Time?

18s from the start of the event isn’t a lot of time. Add in 5 seconds to even recognize an event is even happening and it really shortens the amount of time to correct.


I completely agree Matt - but that may have been Feith's point that for us "old timers" using that pitch trim - IF it was available - would have been second nature, but to someone conditioned to let the airplane do most of the trimming, it may not have occurred to them.

Please don't take any of my arm chair analysis as chastising the crew in any way. Good pilots tend to attempt to put themselves in these positions not only to learn from them, but to empathize and pay our respects.
 
TTailedTiger
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 4:14 pm

SomebodyInTLS wrote:
ALERT wrote:
everyone is trying to avoid talking about or rule out suicide due to the cvr ( and im not declaring this happened or denying the possibility of other causes) but it really could simply be that the pilot flying decided he was done and nosed it over.


Oh good grief, not this nonsense yet again. (You are FAR from the first person to suggest it - it's the foregone conclusion for many people after every single incident these days)

I don’t like it but it really is occums razor


No, it really is not. There have been TWO, count them, TWO conclusive cases of pilot suicide... EVER!

It is utterly irresponsible to suggest suicide or other foul play without good reason to think so since the statistics clearly show that it almost never happens outside of movies.

To accuse people who are dead and cannot defend themselves of criminal activity that they are very likely NOT to have taken is insulting to them and their families. And it draws attention away from the actual investigation.


No one in this thread is part of the investigation. You act like we are little kids pulling on the coattails of the investigators. He asked a well-thought out question and had enough reason to ask it. And I count three cases of pilot suicide (Egypt Air, Silk Air, Germanwings) and an attempted fourth case (FedEx). No one has claimed that this is what happened. But it is certainly not offensive to discuss the idea since it has happened before.
 
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OA940
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 4:19 pm

Haven't read the 29 pages of posts here so my apologies if this has been suggested before, but could this be a West Air Sweden 294 situation? I mean sure pilot suicide looks likely, but if a pilot wanted to bring a plane down I doubt he would've waited until approach. Whereas a failure like on that flight would explain the nose down inputs.
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VeeCee
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 4:33 pm

ALERT wrote:
I don’t like it but it really is occums razor


No one has ruled out anything yet, but seriously this is a pointless statement. When a plane crashes intact, pilot suicide will ALWAYS be the simplest possible answer because it is a single point of failure. A bad action by one person.

But modern planes are immensely complicated machines with millions of individual parts supplied by hundreds of suppliers. A single plane has more computing power and complexity than the entire Apollo program. And every day hundreds of pilots, ordinary people fueled by coffee and subject to the same prejudices and limitations manage to guide them through snow and ice and lightning safely to their destinations. They are trained and education and practiced, but are otherwise normal, fallible humans like your average keyboard warrior.

So when accidents happen, it's almost never one bad actor, one bad part, one bad decision. It's messy and complicated and that's GOOD. It's the very basis of modern aviation safety. That there isn't a single point of failure. That redundancy is built into every aspect of aircraft design and operation.
 
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SomebodyInTLS
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 4:49 pm

VeeCee wrote:
ALERT wrote:
I don’t like it but it really is occums razor


No one has ruled out anything yet, but seriously this is a pointless statement.


I don't think people know what Occam's Razor is... It is to eliminate complexity AND ASSUMPTIONS.

When your entire "solution" is NOTHING BUT A SINGLE ASSUMPTION, then that is the opposite of using Occam's Razor!
"As with most things related to aircraft design, it's all about the trade-offs and much more nuanced than A.net likes to make out."
 
mzlin
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 5:10 pm

Whiplash6 wrote:
OldB747Driver wrote:
ALERT wrote:
...it seems like there is alot of mental gymnastics trying to explain how this could have happened with spatial disorientation, not understanding how automation is affecting something and reacting incorrectly etc., and everyone is trying to avoid talking about or rule out suicide due to the cvr ( and im not declaring this happened or denying the possibility of other causes) but it really could simply be that the pilot flying decided he was done and nosed it over. Possibly the other pilots weren’t paying attention ( long day, not their leg) and gave him is opportunity. This can often be a spontaneous act without a declaration. The cvr is easily explainable if the person didn’t want it declared suicide ( insurance). Make a vague statement about control issues and point the plane to the ground. No time for anyone to react and 18 seconds later its over.
I don’t like it but it really is occums razor


It is understandable that folks would suspect intentionality to what seems to be improbable, if not impossible, but those of us who have done this for many, many years can appreciate both the situation and the mentality of the pilots in this situation; given both the wording of the initial NTSB CVR analysis ("crew communication consistent with loss of control") and the flight profile.

Spatial disorientation happens, but at this level, it would be reasonable to suspect at least ONE of the pilots would react correctly or at least make enough of a verbal statement that the other crewmember would be amendable to their disorientation - that is part of the fundamental training at this level of flying / CRM. Thus, incapacitating disorientation is highly unlikely.

As far as intentionality ("he was done and nosed it over") disregards the two other pilots who would not be having a conversation "consistent with loss of control", but a conversation consistent with "WTF are you doing?!?" Adding to this, this crew was in the middle of weather avoidance and rapidly changing maneuvers - likely NONE of this would have occurred if one pilot had nefarious intent. Thus, this too is not very likely. Possible but not likely.

IMHO, the level-off at 6200 with slight climb to 6300 before the nose-over began is the initiating event - an unintended command to the autothrottles resulted in max thrust; the thrust line is below the CG, thus the thrust increase caused the slight pitch up, which the autopilot reacted to with a rapid pitch down to counteract and continue the descent. Something malfunctioned right then and there, and I'm pretty sure it wasn't a pilot. Now could a pilot have caused the error? Thats possible, maybe even likely, but something mechanical (autopilot, elevator, etc) complicated the scenario exponentially.


It’s difficult to explain 49 degrees of pitch down. That’s way outside the peramters of the autopilot.


FlyDubai got to exactly 49° pitch down based on trim commands of the crew presumably from somatogravic illusion as the plane accelerated at TOGA power
 
mzlin
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 5:13 pm

scbriml wrote:
Whiplash6 wrote:
It’s difficult to explain 49 degrees of pitch down. That’s way outside the peramters of the autopilot.


Which makes it equally difficult to understand the view that the crew "were fighting automation to the end".


As far as I can tell, that quote is an unsubstantiated rumor by one person on Facebook. The person is not part of the investigative team and Facebook is not an official newsletter of the NTSB. So we should just wait for a real NTSB statement.
 
WPvsMW
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 6:16 pm

BlueberryWheats wrote:
WPvsMW wrote:
hmmm... think about your question. You are asking if experienced pilots confused the throttles with the yoke/rudder?


Don't be a condensing prick. It's a valid question for someone possibly not in the know. After all, the speed and heading inputs on the 767 glare shield are three digit numerical inputs with a round knob underneath, and they are right next to each other.


If there is a condensing cycle, I hope there is an expansion cycle.
 
WPvsMW
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 6:35 pm

OldB747Driver wrote:
in reference to several posts above..


OldB747Driver, welcome to a.nut. Very informative posts.
 
mxaxai
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 7:21 pm

OldB747Driver wrote:
I doubt there is a Memory Item titled "Rapid Nose-Over and Uncommanded Autothrottles to Max Thrust".

In a glider, if the winch cable breaks, "Rapid Nose-Over" is a memory item to prevent an imminent stall.
No thrust available, tho. :p

"Throttles to Max Thrust" would be a memory item for windshear, correct? But you would usually try to hold the nose stable, or at least maintain airspeed, rather than push the plane into a dive.
Even if one pilot overreacted, the yoke is right in front of the other one. It should be quite noticeable if full nose down input is given for several seconds.
 
Whiplash6
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 7:36 pm

mxaxai wrote:
OldB747Driver wrote:
I doubt there is a Memory Item titled "Rapid Nose-Over and Uncommanded Autothrottles to Max Thrust".

In a glider, if the winch cable breaks, "Rapid Nose-Over" is a memory item to prevent an imminent stall.
No thrust available, tho. :p

"Throttles to Max Thrust" would be a memory item for windshear, correct? But you would usually try to hold the nose stable, or at least maintain airspeed, rather than push the plane into a dive.
Even if one pilot overreacted, the yoke is right in front of the other one. It should be quite noticeable if full nose down input is given for several seconds.

Max thrust would be a common mistake in that situation. GA power for windshear. Max thrust for TERRAIN avoidance.
 
deltadart106
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 7:50 pm

Whiplash6 wrote:
mxaxai wrote:
OldB747Driver wrote:
I doubt there is a Memory Item titled "Rapid Nose-Over and Uncommanded Autothrottles to Max Thrust".

In a glider, if the winch cable breaks, "Rapid Nose-Over" is a memory item to prevent an imminent stall.
No thrust available, tho. :p

"Throttles to Max Thrust" would be a memory item for windshear, correct? But you would usually try to hold the nose stable, or at least maintain airspeed, rather than push the plane into a dive.
Even if one pilot overreacted, the yoke is right in front of the other one. It should be quite noticeable if full nose down input is given for several seconds.

Max thrust would be a common mistake in that situation. GA power for windshear. Max thrust for TERRAIN avoidance.


Dumb question, but do pilots not use the full power during takeoff/go around?
 
Whiplash6
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 8:07 pm

deltadart106 wrote:
Whiplash6 wrote:
mxaxai wrote:
In a glider, if the winch cable breaks, "Rapid Nose-Over" is a memory item to prevent an imminent stall.
No thrust available, tho. :p

"Throttles to Max Thrust" would be a memory item for windshear, correct? But you would usually try to hold the nose stable, or at least maintain airspeed, rather than push the plane into a dive.
Even if one pilot overreacted, the yoke is right in front of the other one. It should be quite noticeable if full nose down input is given for several seconds.

Max thrust would be a common mistake in that situation. GA power for windshear. Max thrust for TERRAIN avoidance.


Dumb question, but do pilots not use the full power during takeoff/go around?


Not typically for takeoff. In airliners most all takeoffs are reduced thrust takeoffs to preserve the engines. Go-arounds use Go-Around thrust which is a thrust setting slightly less than Max.. The only time a max thrust takeoff is done is when your performance absolutely needs it to meet specific parameters or at maintenance’s requests.
 
adamant365
Posts: 11
Joined: Wed Jun 27, 2007 10:06 am

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 8:12 pm

deltadart106 wrote:
Whiplash6 wrote:
mxaxai wrote:
In a glider, if the winch cable breaks, "Rapid Nose-Over" is a memory item to prevent an imminent stall.
No thrust available, tho. :p

"Throttles to Max Thrust" would be a memory item for windshear, correct? But you would usually try to hold the nose stable, or at least maintain airspeed, rather than push the plane into a dive.
Even if one pilot overreacted, the yoke is right in front of the other one. It should be quite noticeable if full nose down input is given for several seconds.

Max thrust would be a common mistake in that situation. GA power for windshear. Max thrust for TERRAIN avoidance.


Dumb question, but do pilots not use the full power during takeoff/go around?

Pilots rarely use max thrust on takeoff. Some examples where they would: MTOW (Max Takeoff Weight - even then not always), contaminated runway (snow, ice, standing water), expectation of wind shear or strong crosswinds (I think). There are probably others I'm missing. As for go-around, it depends on the aircraft type. I know for sure the 777 uses "steps" of go around thrust: a first push selects power for a 2000 fpm climb and a second commands full go around power (which still isn't max thrust). Going immediately to go-around (TOGA) power on a 777 at light weight would send it up like a rocket ship.
 
Endeavor
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 8:25 pm

ALERT wrote:
IMHO, the level-off at 6200 with slight climb to 6300 before the nose-over began is the initiating event - an unintended command to the autothrottles resulted in max thrust; the thrust line is below the CG, thus the thrust increase caused the slight pitch up, which the autopilot reacted to with a rapid pitch down to counteract and continue the descent. Something malfunctioned right then and there, and I'm pretty sure it wasn't a pilot. Now could a pilot have caused the error? Thats possible, maybe even likely, but something mechanical (autopilot, elevator, etc) complicated the scenario exponentially.


Given what has been made public along with information provided to me by others, this is where I'm at as well.
 
OldB747Driver
Posts: 49
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 9:32 pm

mxaxai wrote:
"Throttles to Max Thrust" would be a memory item for windshear, correct? But you would usually try to hold the nose stable, or at least maintain airspeed, rather than push the plane into a dive.
Even if one pilot overreacted, the yoke is right in front of the other one. It should be quite noticeable if full nose down input is given for several seconds.


In general, imminent terrain warnings ("Whoop-Whoop 'Pull Up!") would require an "Escape Maneuver", the exceptions being when you can positively determine it to be a false alarm noting that not only terrain but obstructions in the EGPWS database such as radio antenna can trigger such a warning. The escape maneuver is, as it is titled, whatever the aircraft has to reverse any descent and begin a maximum performance climb, which would include Max Thrust. On modern jets with digital controls, there are detents for setting certain power settings and max thrust is everything the motor has to give. It is worth noting that max thrust is achieved by simply pushing the power levers to their absolute limit without regard to anything except the mechanical stop on the center pedestal. In reality the resultant power would likely cause the motors to exceed at least one of their normal operating parameters and, after landing, would require maintenance inspections, if not replacement, hence it is not a regular "go-to" procedure.

If the NTSB narrative is accurate (or similarly, if our understanding of what they are saying is correct) there was no logical reason any terrain alert would occur at 6200' anywhere around Houston but if you're driving around IMC and told to descend quickly and then get a [false] terrain alert, most pilots, especially a pilot who was not familiar with the Houston area would likely respond to it; the company's procedure may also mandate it under those conditions. That would certainly explain a max thrust setting, but not the innuendo that that the crew "fought the automation all the way down" - the aircraft was never stalled or even close to it as far as I understand the current narrative. [Edit: Although maybe a rapid pull-up combined with max thrust created an accelerated stall? That would certainly present a rapidly increasing descent, regardless of airspeed and very difficult to discipline yourself to "lower the AOA / nose to recover " and possibly a "too slow" recovery.]

As far as being aware of what the other pilot is doing, well, officially the duties are divided into "Pilot Flying" and "Pilot Monitoring", which should indicate what the "non-flying" pilot should ALWAYS be doing, but "your mileage may vary". Since the Captain's certificate is ALWAYS on the line, especially when the workload gets high like it was here, they are very attentive to all activities on the flight deck.
 
OldB747Driver
Posts: 49
Joined: Tue Mar 12, 2019 11:40 pm

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 9:54 pm

Oh, and apologies, mxaxai, wind shear is really of main concern at low altitude, thus making terrain impact the threat which is how that explanation went in that direction. Wind shear at altitude usually occurs with plenty of airspeed as well as altitude to recover so it is not the threat it would be much lower. Again, 6200 MSL in the Houston area at 230 KIAS is not really a "danger zone" - I would imagine the stall speed clean of the B767 at that weight was probably 170 or so? They would have had to encounter a 60 knot shear to tailwind for that to occur, and assuming the stall system was working properly, would have set off alarms, stick shaker and pusher - and the NTSB specifically stated none of that occurred.

Sorry for the explanation creep...
 
OldB747Driver
Posts: 49
Joined: Tue Mar 12, 2019 11:40 pm

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 10:35 pm

Well, now you got me thinking, mxaxai...

Rethinking the wind shear scenario, in my experience most aircraft's wind shear warning systems were only operative up to 2500 AGL so I wouldn't expect a windshear warning to be produced regardless of the wind shear present where they were at 6200 MSL. Nevertheless, looking at the radar/dopler charts the NTSB produced in their update, it is interesting that there is a yellow spot on the dopler chart just east of Anahuac, probably close to where the infamous 18 seconds began. The legend on the left side of that chart indicates a potential 60+ knot shear!!! (Yellow is 55 knots AWAY from dopler station, and very close to a dark green area of 5 knots TOWARD the station...)

The mystery deepens...

Image
 
mxaxai
Posts: 1180
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Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 10:57 pm

OldB747Driver wrote:
Sorry for the explanation creep...

No worries! It's always nice to get an in-depth view.

Note that I'm not suggesting that this plane crashed directly due to wind shear. I had been thinking more along the lines of: Wind shear warning -> pilot input max Thrust, pitch up -> Spatial disorientation, pitch down -> crash. If the warning is inhibited over 2500' AGL and the stick shaker didn't activate (per NTSB), there wouldn't have been a clear signal to do so. So that theory becomes less likely.
Of course they could've seen the speed decay on their instruments but if they were monitoring the instruments they should've noticed the unusual attitude immediately. So in this case, either there was an event that distracted them from their displays (alerts, navigation, communication, etc. - maybe the weather) or the onset of the dive was too fast to react - but a sudden dive would again be far more noticeable and should trigger an immediate response. Of course 18 seconds is not much time ...
 
OldB747Driver
Posts: 49
Joined: Tue Mar 12, 2019 11:40 pm

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Wed Mar 13, 2019 11:33 pm

mxaxai wrote:
Note that I'm not suggesting that this plane crashed directly due to wind shear. I had been thinking more along the lines of: Wind shear warning -> pilot input max Thrust, pitch up -> Spatial disorientation, pitch down -> crash. If the warning is inhibited over 2500' AGL and the stick shaker didn't activate (per NTSB), there wouldn't have been a clear signal to do so. So that theory becomes less likely.
Of course they could've seen the speed decay on their instruments but if they were monitoring the instruments they should've noticed the unusual attitude immediately. So in this case, either there was an event that distracted them from their displays (alerts, navigation, communication, etc. - maybe the weather) or the onset of the dive was too fast to react - but a sudden dive would again be far more noticeable and should trigger an immediate response. Of course 18 seconds is not much time ...


After really looking at this angle it becomes a lot more possible, however, especially if any recovery was hindered by not "disconnecting the automation" as the quote from Greg Feith is attributed to having been stated.
 
PlanesNTrains
Posts: 9526
Joined: Tue Feb 01, 2005 4:19 pm

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Thu Mar 14, 2019 1:04 am

TTailedTiger wrote:
SomebodyInTLS wrote:
ALERT wrote:
everyone is trying to avoid talking about or rule out suicide due to the cvr ( and im not declaring this happened or denying the possibility of other causes) but it really could simply be that the pilot flying decided he was done and nosed it over.


Oh good grief, not this nonsense yet again. (You are FAR from the first person to suggest it - it's the foregone conclusion for many people after every single incident these days)

I don’t like it but it really is occums razor


No, it really is not. There have been TWO, count them, TWO conclusive cases of pilot suicide... EVER!

It is utterly irresponsible to suggest suicide or other foul play without good reason to think so since the statistics clearly show that it almost never happens outside of movies.

To accuse people who are dead and cannot defend themselves of criminal activity that they are very likely NOT to have taken is insulting to them and their families. And it draws attention away from the actual investigation.




No one in this thread is part of the investigation. You act like we are little kids pulling on the coattails of the investigators. He asked a well-thought out question and had enough reason to ask it. And I count three cases of pilot suicide (Egypt Air, Silk Air, Germanwings) and an attempted fourth case (FedEx). No one has claimed that this is what happened. But it is certainly not offensive to discuss the idea since it has happened before.


1. It doesn't have to be "Pilot Suicide" - it can just be "got access to the cockpit suicide".
2. Wasn't there an E190 in Africa that was the victim of a pilot suicide?
3. This isn't the actual investigation so not sure it's all that critical to not discuss certain things.
4. Suggesting pilot suicide is certainly more realistic and less egregious than suggesting it was aliens or a meteor shower.

but:

5. Pilot Suicide seems like the lazy guess more and more of late.
6. It really seems disrespectful for it to be repeatedly suggested in crashes before we have anything more official from investigators.
7. The investigators would certainly have an indication by now of a possible suicide just from listening to the cvr and reading the FDR.
8. The overriding cause for most crashes - perhaps the vast majority - is some mix of mechanical/systems issues and/or pilot/people error.
-Dave


MAX’d out on MAX threads. If you are starting a thread, and it’s about the MAX - stop. There’s already a thread that covers it.
 
glideslope900
Posts: 137
Joined: Sun Feb 24, 2019 5:27 am

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Thu Mar 14, 2019 1:47 am

Whiplash6 wrote:
mxaxai wrote:
OldB747Driver wrote:
I doubt there is a Memory Item titled "Rapid Nose-Over and Uncommanded Autothrottles to Max Thrust".

In a glider, if the winch cable breaks, "Rapid Nose-Over" is a memory item to prevent an imminent stall.
No thrust available, tho. :p

"Throttles to Max Thrust" would be a memory item for windshear, correct? But you would usually try to hold the nose stable, or at least maintain airspeed, rather than push the plane into a dive.
Even if one pilot overreacted, the yoke is right in front of the other one. It should be quite noticeable if full nose down input is given for several seconds.

Max thrust would be a common mistake in that situation. GA power for windshear. Max thrust for TERRAIN avoidance.


Windshear escape is max power at my airline. I would assume this is the case at most airlines. Windshear is not a joke.

I don’t believe weather was the cause of this accident. Mechanical failure is most likely. That elevator needs to be examined very closely.
 
Whiplash6
Posts: 130
Joined: Sun Feb 12, 2017 2:30 am

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Thu Mar 14, 2019 1:48 am

glideslope900 wrote:
Whiplash6 wrote:
mxaxai wrote:
In a glider, if the winch cable breaks, "Rapid Nose-Over" is a memory item to prevent an imminent stall.
No thrust available, tho. :p

"Throttles to Max Thrust" would be a memory item for windshear, correct? But you would usually try to hold the nose stable, or at least maintain airspeed, rather than push the plane into a dive.
Even if one pilot overreacted, the yoke is right in front of the other one. It should be quite noticeable if full nose down input is given for several seconds.

Max thrust would be a common mistake in that situation. GA power for windshear. Max thrust for TERRAIN avoidance.


Windshear escape is max power at my airline. I would assume this is the case at most airlines. Windshear is not a joke.

I don’t believe weather was the cause of this accident. Mechanical failure is most likely. That elevator needs to be examined very closely.

Great. That’s not our procedure. Max power if you absolutely have to.
 
glideslope900
Posts: 137
Joined: Sun Feb 24, 2019 5:27 am

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Thu Mar 14, 2019 1:51 am

Whiplash6 wrote:
glideslope900 wrote:
Whiplash6 wrote:
Max thrust would be a common mistake in that situation. GA power for windshear. Max thrust for TERRAIN avoidance.


Windshear escape is max power at my airline. I would assume this is the case at most airlines. Windshear is not a joke.

I don’t believe weather was the cause of this accident. Mechanical failure is most likely. That elevator needs to be examined very closely.

Great. That’s not our procedure. Max power if you absolutely have to.


Our windshear system activates below 2,500 AGL as the wise old 747 guy said...so that low to the ground is the only time we would go max thrust. At 6,800 AGL going max thrust would be very out of the ordinary. Also with the amount of planes flying through this same area a weather event seems highly unlikely.
 
Lrockeagle
Posts: 145
Joined: Wed Oct 06, 2004 1:40 am

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Thu Mar 14, 2019 2:06 am

glideslope900 wrote:
Whiplash6 wrote:
glideslope900 wrote:

Windshear escape is max power at my airline. I would assume this is the case at most airlines. Windshear is not a joke.

I don’t believe weather was the cause of this accident. Mechanical failure is most likely. That elevator needs to be examined very closely.

Great. That’s not our procedure. Max power if you absolutely have to.


Our windshear system activates below 2,500 AGL as the wise old 747 guy said...so that low to the ground is the only time we would go max thrust. At 6,800 AGL going max thrust would be very out of the ordinary. Also with the amount of planes flying through this same area a weather event seems highly unlikely.

Good point about the other traffic. The times I’ve flown into Houston there was lots of “in trail” traffic, quotations because I don’t know how that is described. Seems if I fly through something then the guy behind me would as well
Lrockeagle
14 years ago

I got $20 says AA takes their 787's with GE powerplants. Just a hunch. Any takers?
 
glideslope900
Posts: 137
Joined: Sun Feb 24, 2019 5:27 am

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Thu Mar 14, 2019 2:34 am

Lrockeagle wrote:
glideslope900 wrote:
Whiplash6 wrote:
Great. That’s not our procedure. Max power if you absolutely have to.


Our windshear system activates below 2,500 AGL as the wise old 747 guy said...so that low to the ground is the only time we would go max thrust. At 6,800 AGL going max thrust would be very out of the ordinary. Also with the amount of planes flying through this same area a weather event seems highly unlikely.

Good point about the other traffic. The times I’ve flown into Houston there was lots of “in trail” traffic, quotations because I don’t know how that is described. Seems if I fly through something then the guy behind me would as well


Not only the guy behind you, but dozens of other aircraft both ahead and behind you. Arrival procedures are standardized.
 
kaneporta1
Posts: 729
Joined: Wed Jun 01, 2005 12:22 am

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Thu Mar 14, 2019 3:41 am

Could pitot icing have produced false low airspeed (and maybe climb rate) readings? This could have caused the crew to firewall the engines and push the nose down to avoid the perceived oncoming stall? The turbulence just before the loss of control could had been interpreted as stall buffet and added to the confusion.
I'd rather die peacefully in my sleep, like my grandfather, not terrified and screaming, like his passengers
 
tjerome
Posts: 287
Joined: Fri Sep 09, 2016 3:03 am

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Thu Mar 14, 2019 3:58 am

kaneporta1 wrote:
Could pitot icing have produced false low airspeed (and maybe climb rate) readings? This could have caused the crew to firewall the engines and push the nose down to avoid the perceived oncoming stall? The turbulence just before the loss of control could had been interpreted as stall buffet and added to the confusion.


Accident occurred around 1840Z, here is the last METAR prior:
KIAH 231802Z 32015G24KT 10SM FEW035 SCT060 BKN080 BKN250 22/12 A2992 RMK AO2 T02220117=

KIAH field elevation 97 feet. Using the rule of temperature decreases 2 degrees C per 1,000 feet, it would've been about 8 degrees C at 7,000 feet. 46 degrees F. Sure icing is a possibility, anything is at this point, but I don't think it is likely.
 
simking
Posts: 5
Joined: Fri Sep 19, 2008 3:18 am

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Thu Mar 14, 2019 6:18 am

Does anyone know about the cargo weight? could a cargo shift throw the CG off causing issues?
 
PlanesNTrains
Posts: 9526
Joined: Tue Feb 01, 2005 4:19 pm

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Thu Mar 14, 2019 7:20 am

simking wrote:
Does anyone know about the cargo weight? could a cargo shift throw the CG off causing issues?


The consensus throughout this thread has been that the weight is likely not close to maximum because it's Amazon stuff - pkgs, etc. - and that the containers were likely packed in pretty good. Additionally, there's the whole issue of why they didn't shift at takeoff which would be the most likely time if they were gonna do so.
-Dave


MAX’d out on MAX threads. If you are starting a thread, and it’s about the MAX - stop. There’s already a thread that covers it.
 
wjcandee
Posts: 7989
Joined: Mon Jun 05, 2000 12:50 am

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Thu Mar 14, 2019 8:30 am

I noted with interest Whiplash6's observations about the use of max power to the effect that his company specifies GA power for windshear. Thinking that this could be the same here, I went back to that NTSB press release to be sure that they had indeed said that the aircraft went to MAX power. And indeed that's what they say. Whip also said that it's a common mistake, so the distinction may not mean much here, but it is interesting. I began to wonder what -- if any -- are the circumstances in which automation would command MAX power, or is that a clue that it was hand-applied? Having lived in Dallas, I tend to think of Texas, outside of the Hill Country, as being pretty dang flat, so one wouldn't be worried about terrain at 6200 feet and wouldn't be applying max power to avoid it.

And I noticed a couple of other clues for between-the-lines readers. The release says that ADS-B reported a selected heading of 270. So plainly that's what's dialed in, but does that necessarily mean that the aircraft is operating in response to the heading in the window? If we believe Feith that the autopilot was coupled, then does this account for the straight 270-degree heading all the way down? And does that unvarying heading tend to support the idea that the autopilot was on? Is there anything significant about this in terms of controllability?

I also thought about the recitation that they would need to descend to 3000 feet expeditiously. I don't remember hearing this on LiveATC, but we know that LiveATC didn't get every bit of communication between ATC and the accident aircraft. Does this imply that they were cleared to descend to 3000, or could ATC have told them that and then stepped them down? I hadn't attached any significance to the fact that they levelled briefly at 6200 feet; just assumed that they were doing that intentionally. If they dialed in a desired altitude of 3000 and descent rate and autopilot was on, query why they would level.

It does seem like some combination of manual inputs with automation doing certain other things. I'm not smart enough to interpret it all, but I think it may be worth highlighting that 270 heading, 270 being in the window, the fact that NTSB keeps repeating 270 as if that straight heading is significant, the (perhaps) clearance for an expedited descent to 3000 feet, the levelling at 6200 feet, the brief climb and advancement of the throttles to MAX, then followed by the (apparently-manually-commanded) nose-over to an unusual descending pitch, and finally the continuous levelling to 20 degrees down pitch.

NTSB didn't mention spoilers. I'm curious about that because when folks have mentioned spoilers before, they probably hadn't known that the aircraft was told to descend expeditiously from 12,000 to 3,000. But then NTSB does seem to suggest that there was no actual stall, b/c no stick shaker.

As with my past highlighting of the "clues", there is somebody that can draw lines of possibility through them. But as much as people say that NTSB hasn't said much, I think they have actually given us a lot.
 
Western727
Posts: 1656
Joined: Wed Jan 03, 2007 12:38 pm

Re: Atlas Air 3591 Down in Trinity Bay, Texas

Thu Mar 14, 2019 1:12 pm

wjcandee wrote:
I noted with interest Whiplash6's observations about the use of max power to the effect that his company specifies GA power for windshear. Thinking that this could be the same here, I went back to that NTSB press release to be sure that they had indeed said that the aircraft went to MAX power. And indeed that's what they say. Whip also said that it's a common mistake, so the distinction may not mean much here, but it is interesting. I began to wonder what -- if any -- are the circumstances in which automation would command MAX power, or is that a clue that it was hand-applied? Having lived in Dallas, I tend to think of Texas, outside of the Hill Country, as being pretty dang flat, so one wouldn't be worried about terrain at 6200 feet and wouldn't be applying max power to avoid it.


Very good point. Even the Hill Country, which I fly over a lot these days as a GA pilot, is fairly flat with little over 2,000' (the highest elevation, in Kimble County, is 2,460')...and metro Houston is practically sea level.

wjcandee wrote:
NTSB didn't mention spoilers. I'm curious about that because when folks have mentioned spoilers before, they probably hadn't known that the aircraft was told to descend expeditiously from 12,000 to 3,000. But then NTSB does seem to suggest that there was no actual stall, b/c no stick shaker.


I'm reminded of AA965 at Cali where the spoilers were left extended, likely (albeit not conclusively) making it impossible for the 752 to clear the peak...
Jack @ AUS

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