Atlas 767, Houston

[Chris Foss]

I'm nowhere up to speed on this, but it all seems to come down to 'did he or didn't he' ?

Some cargo pilots have brought up the trim/maintenance issues from a while back regarding the 767, but I haven't seen any further reference.

The statements from NTSB do not mention stab or trim changes, just elevator deflection (amended from pilot input).

I can't think of any way the control system can misinterpret pilot input to shove the nose down. Trim maybe, but that would be obvious on data.

FDR should show stick forces vs CS deflections and if there was a serious discrepancy between that data, we would be reading a very different statement.

I can't think of any cargo shift or trim activity that could fool or overwhelm pilot input without showing up in a input/output discrepancy as it clearly did in the cargo 747 in Iraq.

[ocelot]

I don't see that the suicide theory was ever credible. I'm putting my pennies on severe windshear.

[3WE]

I don't see that the suicide theory was ever credible. I'm putting my pennies on severe windshear.

I won’t DISMISS wind shear, but:

-They did not enter the rainstorms
-The rainstorms were not mega Oklahoma tornadic supercells
-They were even near lighter storms
-There were no reports of severe turbulence and passenger injury that I’m aware of that day
-Does not explain full nose down elevator nor full power
-The videos indicate a fairly stable dive vs something turbulence rocked

I’m about 50:50 on freak failure of elevator systems or something deliberate and malicious.

[KPryor]

Over on pprune, someone posted an article from the Wall St Journal regarding the crash with information from "people familiar with the details". As in anonymous sources. The article says the NTSB is currently focusing on pilot error and theorizes the pilots overreacted to the sudden thrust increase. In the article, it is theorized the the plane may have hit turbulent air causing the hand of the PF to accidentally push the thrust levers full forward, causing the nose pitch up followed by the sudden push to nose down and then we all know what happened after that.

I think this theory sounds more than a little ridiculous. I've never had the opportunity to push on thrust levers, but would it really be that likely the above could happen? Next, I find it hard to believe a professional crew would react to that extreme if that actually happened.

[Gabriel]

Over on pprune, someone posted an article from the Wall St Journal regarding the crash with information from "people familiar with the details". As in anonymous sources. The article says the NTSB is currently focusing on pilot error and theorizes the pilots overreacted to the sudden thrust increase. In the article, it is theorized the the plane may have hit turbulent air causing the hand of the PF to accidentally push the thrust levers full forward, causing the nose pitch up followed by the sudden push to nose down and then we all know what happened after that.

I think this theory sounds more than a little ridiculous. I've never had the opportunity to push on thrust levers, but would it really be that likely the above could happen? Next, I find it hard to believe a professional crew would react to that extreme if that actually happened.

Well, we had crews overreacting.
Air France and Colgan pulled up like crazy.

On thing that may have happened, if they were in IMC and in manual flight, is the known somatogravic illusion of pitching up when in fact you are accelerating, which can be counteracted with a strong push down by the pilot. This happened many times in GA airplanes taking off in conditions of very low ceilings or very poor visibility. Although I have never heard of it in a transport category jet.

[KPryor]

I get reacting to that, but this was such a gross overreaction that it seems almost implausible. That being said, I have zero experience in such a situation and can't say with any authority whatsoever that this isn't what happened. It just didn't "sound right" I guess.

[Gabriel]

I get reacting to that, but this was such a gross overreaction that it seems almost implausible. That being said, I have zero experience in such a situation and can't say with any authority whatsoever that this isn't what happened. It just didn't "sound right" I guess.

Actually I agree. I just mentioned one what that something like this could possibly happen. Not that believe that it is likely at all.

[3WE]

Colgan pulled up like crazy.

While dead tired at ~2000 ft AGL in hard IMC.

I struggle to extrapolate to 6000 ft AGL and not_really IMC...

No good evidence of a pull up during that last 5 seconds that were filmed (and which were VMC)

I know you think Colgan pulled up excessively (for 6 seconds), but at that altitude there wasn’t much time AND they were spinning and stuff...

Just can’t reconcile to a full push over dive.

[Gabriel]

Colgan pulled up like crazy.

While dead tired at ~2000 ft AGL in hard IMC.

I struggle to extrapolate to 6000 ft AGL and not_really IMC...

No good evidence of a pull up during that last 5 seconds that were filmed (and which were VMC)

I know you think Colgan pulled up excessively (for 6 seconds), but at that altitude there wasn’t much time AND they were spinning and stuff...

Just can’t reconcile to a full push over dive.

I really don't know what are you talking about.

First, there is some evidence that there might have been a pull up in the last 5 seconds that were filmed and were VMC:

The airplane then pitched nose down over the next 18 seconds to about 49° in response to nose-down elevator deflection. The stall warning (stick shaker) did not activate. The airplane entered a rapid descent reaching an airspeed of about 430 knots. A security camera video captured the airplane in a steep, generally wings-level attitude until impact with the swamp. FDR data indicated that the airplane gradually pitched up to about 20 degrees nose down during the descent.

Was that just Phugoid or there was pull up action? Maybe.

Second, are you talking about the same Colgan that I am? They didn't have too much altitude and time for what? They had a lot of thime, they just needed to... do nothing. It didn't took them long to put the plane in a 1.5Gs CLIMB before totally stalling and then keep pulling up even against the stick pusher.

Anyway, again, I am not saying that the pilots for the 767 just pushed down all the way to the ground in confusion. I am saying that that 18 seconds push down may have been due to the illusion of climbing when you add thrust. May have been. It is just a possibility. Not that I believe that that is what happened.

[3WE]

Second, are you talking about the same Colgan that I am? They didn't have too much altitude and time for what? They had a lot of thime, they just needed to... do nothing. It didn't took them long to put the plane in a 1.5Gs CLIMB before totally stalling and then keep pulling up even against the stick pusher.

I do not defend the relentless pull up... my comment is in the context of after the stall...

2000 feet is not enough to recover from nasty stall-spin...(when tired and disoriented at night in IMC)

6000 feet IS enough to recover from a not_stall...(in not_IMC in daytime)

My opinion............however it is a significant contrast...

Also - I get the somatographic stall...THEN BOTCHED RECOVERY BECAUSE YOUR CONTROLS ARE COMPRIMISED...but with a somatogaphic dive, you still have a working aircraft...

These comments are 75% agreement, 25% argument/clarification.

[Gabriel]

Also - I get the somatographic stall...

The what???? Even if you meant somatogravic, what?

but with a somatogaphic dive, you still have a working aircraft...

I am amusing that you want somatogravic and not that you are making some joke/pun/sarcasm that I am missing.

The thing with the somatogravic illusion is that (unlike the somatogyral illusion) it is persistent in the sense that pitching down doesn't "compensate" the fake "pitching up" sensation due to the acceleration. And while the name is "somato-x" (which means that is a vestibular sensation of the inner ear), in fact (and unlike the somatogyral illusion) it is something that is felt with the tactile sensations of all your body (even inside it), not just the inner ear. That means that you could perceive that you pitched up (due to the acceleration), actively pitch way down and still feel that you are pitching up. The sense of sight, though, is a strong feedback mechanism that "calibrates" the sensation to tell pitch up vs acceleration. This is illusion, including the calibration function of sight, is widely exploited by full-motion simulators that pitch up or down not in response to the pitch of the simulated plane but in response to the acceleration-deceleration.

Next time you fly in coach and have curtains hanging that divide business from coach, look at the curtains during take-off. See how their angle relative to the apparent "vertical" (i.e. their lack of perpendicularity with the floor of the plane) remains about constant throughout the take-off and initial climb. It the curtains can't tell the difference, neither can your inner ear and the rest of you body.

Now, again, the sense of sight should be a strong calibrator. Pilots with experience flying in IMC are trained and used to use the AI as this visual calibrator. But we know that sometimes fail, especially if you are not putting strong attention in the AI. Perhaps they got distracted with some other problem, perhaps the AP disconnected due to some failure and for some reason they had an impulse to firewall the throttles (which other than a lot of acceleration initially caused a pitch up of 4 degrees) and the PF instinctively reacted by pushing down but he was in fact not paying attention to the AI for 18 seconds because he was distracted with the problem that triggered the AP off, and perhaps the PM was focusing in the QRH for that fault or something. Now the view of the real ground, sky and horizon out of the window is much more compelling even if you are using just your peripheral vision. Perhaps by when they came under the clouds base at 50 degrees nose down and 430 knots they immediately recognized their attitude but it was too late: they managed to reduce the pitch down to 20 degrees (i.e. they pulled up 30 degrees) but then they run out of altitude. At 50 degrees nose-down only half of the normal acceleration is used to reduce the vertical speed (because the lift vector is pointing more forward that upwards), and when you pull up at 430 knots the radius of the path is very big and the rate of pitch-up is very slow.

I don't know if they were initially in IMC and, if so, I don't know at what altitude they emerged from the clouds. So I don;t know who valid the above description would be for this case, even as an hypothesis.

Again, do I think that that is what happened? No I don't. Remember this started as a response to KPryor who said "I find it hard to believe a professional crew would react to that extreme if that actually happened". Of course the crew would not just say "hey, I feel like pushing down like crazy" (unless it was a suicidal attempt). So I was just attempting to find a way how this could actually happen.

[3WE]

Gabieee:

I was attempting to add additional reasoning why a full dive input doesn’t make sense...

Not saying it COULDN’T happen but not where I’d place my bet. I note that you were offering a process (not necessarily agreeing) where that MIGHT have happened even though it’s a stretch.

I AM saying that even the Colgan comparison is rather weak for a few reasons...again, not impossible but not really apples to apples either.

[Gabriel]

Gabieee:

I was attempting to add additional reasoning why a full dive input doesn’t make sense...

Ok, got our point. just a clarification:

It doesn't need to be a "full dive input" (if with that you mean full column forward input). At 230 knots or so that they were doing 0.5Gs give you about 3 degrees per second and will be about right to put you at -49 degrees in 18 seconds.

0.5 Gs is a substantial push down, but it is not full forward column. But I agree with you, it doesn't make a lot of sense. As much as the somatogravic illusion is true, you cannot miss a sustained 18 seconds 0.5Gs input. That will make any roller-coasters feel like a carousel horse.

[KPryor]

Just read this article at https://airwaysmag.com/airlines/ntsb-re ... air-crash/ and thought I'd share.

LONDON – The NTSB has released an initial report on the crash of the Atlas Air flight 3591 which crashed on February 23, 40 miles away from Houston’s George Bush Intercontinental Airport.

The report shows that the plane did, in fact, hit a front of extreme weather.

The report shows from ADS-B data that the plane was following a normal descent and arrival procedure into the airport moments before the accident took place.

The data shows the plane descending through 13,800 feet at which point the controller in charge of the aircraft advised the crew of light to heavy precipitation front that was moving along their initially planned flight route and so they should expect to be given vectors around the weather for their arrival.

The pilots were then asked if they would like to be vectored to the north or the west of the weather for their arrival into the airport on runway 26L.

The data shortly after this new approach was agreed shows the plane continuing to descend through 12,000 feet with a ground speed of 290 knots, which the report states are consistent with the arrival procedure of the airport.

A few minutes later the pilots were instructed by ATC to turn to a heading of 270 degrees, the ADS-B data shows that this command was followed out by the crew and at the point of taking the heading the plane was still in a decent passing through 8,500 feet.

The ADS-B data goes on to show that the plane and pilots were complying with all ATC instructions.

It was at 12:38 the data shows that the aircraft levelled off at 6,200 feet and then started a slight climb to 6,300 feet. The Flight Data Recorder, says the report, “indicated that some small vertical acceleration is consistent with the airplane entering turbulence”.

While there is no confirmation from the NTSB on what caused the crash, the data from the FDR and the ADS-B both imply that the aircraft entered turbulence, which was consistent with the pilots’ input to push the throttles to full power, this is a standard procedure for all pilots when they encounter windsheer and the planes steady climb of 4 degrees nose up is consistent with this input.

The data also shows, however, that very shortly after that the plane pitched nose down to around 49 degrees in 18 seconds and the planes speed of 430 knots, there has been no confirmation from the NTSB on whether or not this was a deliberate input or if the aircraft had experienced an extreme downforce, what is clear in this initial report however, is that the stall warner (the stick shake) did not activate.

In the report, a still image is attached from a security camera which caught an image of the aircraft in a 20-degree nose down pitch moments before it made contact with the ground, this image is consistent with the data taken from the FDR which shows that the plane was gradually pulling out of its steep descent.

At this time there has been no comment from the NTSB on what the final cause of the crash was, or what caused the plane to pitch nose down.

[elaw]

Can anyone think of a weather phenomenon that would explain the above? I can't.

Sudden downdraft: airspeed remains about the same, VS goes negative, but pitch would not change significantly. Sudden updraft: the opposite - airspeed remains about the same, VS goes positive, pitch stays about the same. A sudden increase in headwind would cause IAS to increase, but if anything the nose would go up and the airplane would rise, not the opposite. With sudden appearance of a tailwind the airplane might descend and the nose could drop, but IAS would decrease, not increase.

[Gabriel]

Can anyone think of a weather phenomenon that would explain the above? I can't.

An initial upset, which triggered an incorrect pilot reaction, may have been weather related.

[3WE]

Ok, sudden super extreme freak chop broke something causing nose down input..

[ocelot]

On thing that may have happened, if they were in IMC and in manual flight, is the known somatogravic illusion of pitching up when in fact you are accelerating, which can be counteracted with a strong push down by the pilot. This happened many times in GA airplanes taking off in conditions of very low ceilings or very poor visibility. Although I have never heard of it in a transport category jet.

http://www.bst-tsb.gc.ca/eng/rapports-r ... 8q0051.asp

You have now...

[ocelot]

Can anyone think of a weather phenomenon that would explain the above? I can't.

Sudden downdraft: airspeed remains about the same, VS goes negative, but pitch would not change significantly. Sudden updraft: the opposite - airspeed remains about the same, VS goes positive, pitch stays about the same. A sudden increase in headwind would cause IAS to increase, but if anything the nose would go up and the airplane would rise, not the opposite. With sudden appearance of a tailwind the airplane might descend and the nose could drop, but IAS would decrease, not increase.

Remember that ADS-B reports groundspeed.

The scenario I was/am thinking about is a large windshear, large enough that if you're on the ball (as opposed to the many cases we see of "did not monitor airspeed on approach"), you hit TOGA and also pitch down. This has the advantage of explaining the observed behavior and doesn't require unlikely combinations of additional failures. However, it'll have a pretty clear signature in the FDR, so it's readily falsifiable if there's an interim report with the FDR data. And if the shear also came with a large downdraft this might be sticky to get out of. Maybe.

Not sure it's meteorologically credible, but it seems at least possible. See https://www.pprune.org/rumours-news/618 ... st10399550 for actual meteo remarks by a qualified person

[3WE]

Random babbling 1: I’m trying to imagine a goofy scenario where the jump seater got tossed by turbulence over a pilot and landed upside down “wedged” between a pilot and the yoke...(or something medical)(crazy stupid thoughts that immediately beg reasons why this should not_be a cause)

Random babbling 2: Continued “silence” on the CVR- no difinitive statement that there was no foul play... Inference that they are digging more deeply on the psychological aspects of the crew? (or the world is Uber focused on MCAS and approvals- so no updates?)

The deeper weather dive: Interesting- maybe there was a gust front involved but still, no evidence that it was epic in any way, nor is it a good explanation for the extreme, stable, 6000 ft dive.

This is a favorite of an airplane close to a storm- no nose over. https://youtu.be/bsACwJkp0CI. (Yes, not apples to apples, but...)

[3WE]

Some un-named aviation forum

Someone, there

The initial bobble is from turbulence at 6200’. When the FO called for flaps 1, the captain accidentally hit the toga button. Toga didn’t engage until after flaps were set to 1, which then brought engine power to full, and started the initial pitch of 10 degrees nose up. The FO was startled, and shoved the nose forward... The CVR is startling, and baffling. The CA was pulling so hard against the FO that he sheared the pins on the stick and at that point had no control. They were IMC at the time. When they broke out into VMC, the FO said oh schit and started to pull. That was the round out you see. I won’t get into anything more until everything comes out. The records, the CVR, and what happened in the flight deck is truly shocking. They hit a negative 4 G dive initialy on the FOs push. All you hear is stuff hitting the ceiling and at one point a loud thud. They think the thud may have been the JS hitting the ceiling and maybe not wearing the shoulder harness. Like I said, I won’t get into anything more about the background of how it all happened. This is the accident in a nutshell. The facts that will come out are shocking.

A bit too far out for me.

Bobby has said: 1) He told them not stop hiring less experienced people and 2) He is not at liberty to discuss this incident.

Do we think that some parts of this quote might be true???

...but less than 50% of it???

/sharing for the sake of completeness only.

[3WE]

Bobby confirms that the gossip was also gossiped to him.

Some un-named aviation forum

Someone, there

Relentless push-over

Ok...is it possible that a well-meaning, supposedly-well-trained pilot do a total-relentless push over- including breaking the captains control column?

Yes, anything is possible, but once again, incredible eyerolling and SEEMING disbelief that someone would go THAT over-the-top address a control issue. (and yes, I still forgive AA-A330-rudder dude for his low pressure, low movement rudder waggles...it's different if you actually break the control column (of the captain))

[Rabbi O'Genius]

(and yes, I still forgive AA-A300-rudder dude for his low pressure, low movement rudder waggles...

fixed

[J]

[Federal Register Volume 85, Number 122 (Wednesday, June 24, 2020)] [Notices] [Page 37963]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 2020-13747]

=======================================================================
-----------------------------------------------------------------------
NATIONAL TRANSPORTATION SAFETY BOARD - Sunshine Act Meeting
TIME AND DATE: 9:30 am, Tuesday, July 14, 2020.
PLACE: Virtual.

STATUS: The one item may be viewed by the public through webcast only.
MATTERS TO BE CONSIDERED: 65227 Aircraft Accident Report: Rapid Descent and Crash into Water, Atlas Air Inc. Flight 3591, Boeing 767-375BCF, N1217A, Trinity Bay, Texas, February 23, 2019.

CONTACT PERSON FOR MORE INFORMATION: Candi Bing at (202) 590-8384 or by email at bingc@ntsb.gov.

Media Information Contact: Keith Holloway by email at keith.hollow@ntsb.gov or at (202) 314-6100.
This meeting will take place virtually. The public may view it through a live or archived webcast by accessing a link under ``Webcast of Events'' on the NTSB home page at www.ntsb.gov.
There may be changes to this event due to the evolving situation concerning the novel coronavirus (COVID-19). Schedule updates,
including weather-related cancellations, are also available at www.ntsb.gov.
The National Transportation Safety Board is holding this meeting under the Government in the Sunshine Act, 5 U.S.C. 552(b).

Dated: Monday, June 22, 2020.
LaSean R McCray,
Alternate Federal Register Liaison Officer.
[FR Doc. 2020-13747 Filed 6-22-20; 4:15 pm]
BILLING CODE 7533-01-P

[KPryor]

Could be a pretty interesting one to watch.