Talk:Flydubai Flight 981

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Czech Airlines divert[edit]

This is FlightRadar24 data of Czech Airlines flight OK914 / CSA914 from Prague to Rostov on 18 March 2016, which diverted to Krasnodar.

https://www.flightradar24.com/data/flights/ok914/#9232f55 — Preceding unsigned comment added by 178.143.107.35 (talk) 09:24, 19 March 2016 (UTC)[reply]

Relevance ? MilborneOne (talk) 09:43, 19 March 2016 (UTC)[reply]
None, it was a different day. Mjroots (talk) 10:40, 19 March 2016 (UTC)[reply]
It arrived to Rostov shortly after midnight, meaning in the early hours of 19 March 2016 local time. It diverted to Krasnodar just a few hours before FlyDubai crashed. Relevance: ABSOLUTE. The pilots decided not to land in Rostov due to weather conditions. Had the pilots of FlyDubai made the same decision a few hours later, the crash would not have happened.
You are wrong because the crash did not occur due to wind, as seen from the video, ATC audio and Flightradar24. The aircraft was at 4000 feet when the incident occurred, the wind was not even a contributing cause. It made two landing attempts which is absolutely a reasonable decision in these wind conditions. Aeroflot's flight 1166 made three attempts before diverting. FlyDubai only made two. It would probably consider diverting to Krasnodar after the second go-around, or waiting in a holding pattern for some more time. The Czech flight is irrelevant because it did not attempt landing, unlike the Aeroflot flight which tried 3 times, and which we mention in the article. The Czech flight was merely waiting in the holding pattern and did not even descend to pattern altitude. --Anthony Ivanoff (talk) 11:05, 19 March 2016 (UTC)[reply]
Which is relevant. Because they correctly assessed the situation and did not even attempt to land in these conditions. This is what FlyDubai pilots should have done. — Preceding unsigned comment added by 178.143.107.35 (talk) 11:07, 19 March 2016 (UTC)[reply]
Again, there was nothing wrong with the conditions at 4000 feet above ground, and Aeroflot made 3 successful go-arounds. So an aircraft that diverted due to the wind is irrelevant. It is absolutely a normal operating procedure to land with these wind conditions. The plane did not crash due to the wind at the airport. It's just as if the Czech plane would divert because of a medical emergency: irrelevant to this crash. --Anthony Ivanoff (talk) 11:20, 19 March 2016 (UTC)[reply]
Sorry, if reliable sources indicate the Czech flight is related to the accident then we can report it, we cant make stuff up. MilborneOne (talk) 11:11, 19 March 2016 (UTC)[reply]
I understand. I was just pointing to reliable data (FlightRadar24) showing the presence of another plane in the area, which diverted to Krasnodar. — Preceding unsigned comment added by 178.143.107.35 (talk) 11:16, 19 March 2016 (UTC)[reply]
Absolute majority of sources only report the Aeroflot flight which made 3 attempts and which is a normal operating procedure. --Anthony Ivanoff (talk) 11:19, 19 March 2016 (UTC)[reply]

I have to correct myself. The FlyDubai crash occurred at 01:41 UTC, which was exactly when the Czech Airline flight was arriving to the area and descending to 12,000f. The holding pattern of CSA flight took place shortly after the crash. So, the Czech Airlines flight is not relevant. My apologies. — Preceding unsigned comment added by 178.143.107.35 (talk) 11:27, 19 March 2016 (UTC)[reply]

L:There is a relevance because hours apart with same weather one was safely dierted.Lihaas (talk) 13:33, 19 March 2016 (UTC)[reply]

You are presuming the cause of the accident was the weather, again it is not for us to jump to conclusions. MilborneOne (talk) 14:13, 19 March 2016 (UTC)[reply]

Named pilot was Cypriot, not Greek[edit]

See [1], though it doesn't say he was the captain. 62.228.107.188 (talk) 13:00, 19 March 2016 (UTC)[reply]

Yep, the TV aso mentioned the oddity. Just caught the name, I guess.Lihaas (talk) 13:32, 19 March 2016 (UTC)[reply]
EMERCOM have published the nationalities of everybody onboard here. 62.228.107.188 (talk) 13:52, 19 March 2016 (UTC)[reply]
Thank you, user 62.228.107.188, you are very good at pointing out to the latest and very important development of this story. Daniel (talk) 14:12, 19 March 2016 (UTC)[reply]

Flight Aware tracking log[edit]

I am unsure how this could best be used for this article, however her is a link to the FlightAware flight tracking log for the subject: https://flightaware.com/live/flight/FDB981/history/20160318/1745Z/OMDB/URRR/tracklog .--RightCowLeftCoast (talk) 15:41, 19 March 2016 (UTC)[reply]

British English[edit]

It's safe to say by this point that this article uses British English (localised, 24-hr. time, etc.), so I've added the British English banner to the top of this page. If anyone disagrees, please leave a comment here so that consensus may be established. Cheers! Colonel Wilhelm Klink (Complaints|Mistakes) 22:00, 19 March 2016 (UTC)[reply]

Agree , but would you be so kind check the text of this article from time to time, to ensure that its Britishness is not corrupted? :-) Daniel (talk) 22:29, 19 March 2016 (UTC)[reply]
Sure, but if it's copyedited at some point, the form of English might change depending on the whims of the copyeditor. I've seen it happen before, either from British to American or American to British. The main thing to ensure is conformity throughout the article. Colonel Wilhelm Klink (Complaints|Mistakes) 22:50, 19 March 2016 (UTC)[reply]
Sometimes non-native English speakers keep different input sources, they might not be conscious of that :-) --TerrainAhead ×TALK× 23:38, 19 March 2016 (UTC)[reply]

Flydubai or FlyDubai?[edit]

I noticed that BBC World Service, New York Times Washington Post, Associated Press, Los-Angeles Times and other reputable sources, cited in this article, all spell the airline's name as FlyDubai. So I suggest to use this spelling of the airline's name throughout this article. If anyone disagrees, please leave a comment here so that consensus may be established. Thank you. Daniel (talk) 23:07, 19 March 2016 (UTC)[reply]

You have a point; however, the Wikipedia article for the airline has the spelling as "Flydubai", and so does the company's official website. My opinion is that either spelling is proper, so you should edit as you see fit. Colonel Wilhelm Klink (Complaints|Mistakes) 23:15, 19 March 2016 (UTC)[reply]
The airline appears to describe itself as "flydubai", not "Flydubai" or "FlyDubai". A {{Lowercase title}} template may therefore be appropriate for both this article and the flydubai article. Bahnfrend (talk) 01:54, 21 March 2016 (UTC)[reply]
That template was added when the article was created but it kept getting removed multiple times by trolls..its actually 'flydubai' (no caps whatsoever)...--Stemoc 02:47, 21 March 2016 (UTC)[reply]
The spelling of the phrase "flydubai Flight 981" seems counterintuitive to English spellers, but a case can be made that it is the proper spelling. Either Way, we should establish a consensus here.– Gilliam (talk) 02:50, 21 March 2016 (UTC)[reply]
According to Manual of Style/Capital letters/Trademarks, "for trademarks, editors should ... use the style that most closely resembles standard English text formatting and capitalization rules. For trademarks that are given in mixed or non-capitalization by their owners (such as adidas), follow standard English text formatting and capitalization rules for proper names (in this case, Adidas)." Daniel (talk) 03:10, 21 March 2016 (UTC)[reply]
... and it then goes on to say "The mixed or non-capitalized formatting should be mentioned in the article lead ..." A similar comment is made in Wikipedia:Manual_of_Style/Trademarks#Trademarks that begin with a lowercase letter: "Conventionally, articles usually give the normal English spelling in the lead, followed by a note such as "(stylized as ...)" with the stylized version ..." But neither this article nor the flydubai article does either of these things. And I might add that I think this style rule is both inappropriate and discriminatory - why are we allowed to use "IBM" instead of "Ibm", and "Häagen-Dazs" instead of "Hagen-Daz", but not "flydubai" instead of "Flydubai"? Bahnfrend (talk) 15:34, 21 March 2016 (UTC)[reply]
Despite your disagreement with this Wikipedia policy, are you ready to comply with it? Daniel (talk) 15:57, 21 March 2016 (UTC)[reply]
I'm not advocating non compliance. But I am saying that the policy is inappropriate, and that in any case this article doesn't comply with the style guide. Bahnfrend (talk) 10:36, 22 March 2016 (UTC)[reply]
The Manual of Style does not demand that a special notice about the peculiarities of the trademarks' spelling, should be placed in the lead of all articles, where this trademark is mentioned. I agree, that it is appropriate to point out in the Flydubai article itself, that this airline prefers to spell its name with a lowercase letter at the beginning, but such special notice is absolutely irrelevant in this article about the air crash. Daniel (talk) 11:19, 22 March 2016 (UTC)[reply]
I think the adidas/Adidas example most closely resembles this situation and that we should begin the word with a capital letter. However, I don't think it's appropriate to add a capital in the middle of the word because many trademarks are compound words that don't capitalize the second word within the compound word. Thus, I think that "Flydubai" should be used, not "flydubai" or "FlyDubai". AHeneen (talk) 00:03, 23 March 2016 (UTC)[reply]

Agree, just like airberlin :) --TerrainAhead ×TALK× 00:12, 23 March 2016 (UTC)[reply]

Agree and withdraw my suggestion to use FlyDubai, instead of Flydubai. Daniel (talk) 00:28, 23 March 2016 (UTC)[reply]

New information[edit]

Aviation experts among Wikipedians might probably be interested in the following information which was published recently:

Daniel (talk) 02:08, 20 March 2016 (UTC)[reply]

Ignore the news about "fire on board" before the crash which is seen by the cameras[edit]

Thе bright light that is visible from the cameras before crash is only LANDING LIGHTS that are very powerful and camera distort this bright light to looking as "the plane is on fire". Only information that can be derives from this cameras is that it hit the ground with first left tail section, left wing and nose up (landing lights are directed to the cameras from right) with speed between 18000-24000 feet per minute vertical speed (about 0.3 sec on the cameras for 30-40 meters distance, i.e. 90-120 m/s or about 18000-24000 fpm ). https://www.youtube.com/watch?v=IBJ32eVWVNc — Preceding unsigned comment added by 77.238.65.171 (talk) 10:20, 20 March 2016 (UTC)[reply]

Agree This is just an example of sensationalism, so typical for tabloids. Daniel (talk) 11:20, 20 March 2016 (UTC)[reply]
I agree, but we have the policy Wikipedia:No original research, so we can't say this unless a reliable source says so. AHeneen (talk) 21:15, 20 March 2016 (UTC)[reply]
Guys, it's not any sort of lights. It's a missile falling. Passenger flights don't fly at 60 degree angles and don't land at 60 degrees either, do they? Russians likely accidentally shot that plane somewhere else and made a cover-up. That would explain a lot of things like damaged black boxes. You didn't have damaged black boxes even on MH17 which Russian Buk missile shot. And they say this plane was nearly empty on fuel before impact. And the only video is from some place far far away. No cameras in the airport? Seriously? First bad landing of Flydubai? No, that one is yet to happen. Ibmua (talk) 12:07, 22 March 2016 (UTC)[reply]

I think the light too bright to indicate landing lights. The attitude seemed "flying" in that the nose was down, flashing wingtip lights visible. So hitting "tail first" nose up seems inconsistent with high speed and stable attitude. Markrkrebs (talk) 11:37, 23 March 2016 (UTC)[reply]

Additionally, speed was high before the descent. This suggests strongly that no wind condition could cause loss of control: the aircraft was established on a go-around with good speed. There will be much more data from the recorders so it should be easy to understand what really happened soon. Meanwhile, my speculation is some kind of dramatic failure, not a pilot error or weather. Markrkrebs (talk) 11:30, 24 March 2016 (UTC)[reply]

short of the runway?[edit]

The article currently says "The aircraft crashed about 250m (800ft) short of the runway". If the landing had already been aborted, is "short of the runway" the correct term? Andy Mabbett (Pigsonthewing); Talk to Andy; Andy's edits 13:30, 20 March 2016 (UTC)[reply]

It actually crashed about 250m (800ft) from the edge of the runway, slightly to the left of it, which can be seen now from the photo of the crash location. Thank you for noticing it. Daniel (talk) 15:18, 20 March 2016 (UTC)[reply]
"before the runway threshold" would work. AHeneen (talk) 21:08, 20 March 2016 (UTC)[reply]
it was after the threshold, not before. Daniel (talk) 21:30, 20 March 2016 (UTC)[reply]
I realize that now. When I made my comment, I was replying to the "short of the runway" statement in the first post. AHeneen (talk) 04:08, 21 March 2016 (UTC)[reply]
Since it fall from the sky, I would say it doesn't matter at what point of the runway. Wykx (talk) 21:13, 20 March 2016 (UTC)[reply]
Runways are long. This particular runway is 2,500 metres (8,200 ft), so I think it's useful to point out the location on the runway. AHeneen (talk) 04:08, 21 March 2016 (UTC)[reply]

Flydubai's first crash[edit]

I don't feel like this trivia belongs in the introduction. Is there a better place for it in the article? 62.228.200.32 (talk) 17:09, 20 March 2016 (UTC)[reply]

Well, according to WP:LEAD, the lead section should explain the notability of the article's subject. I think, that is why this piece of information was placed here. This crash was the only one for an airline with an excellent safety record. Daniel (talk) 17:54, 20 March 2016 (UTC)[reply]
? A passenger aircraft crash is notable irrespective of who the operator is. 62.228.200.32 (talk) 18:01, 20 March 2016 (UTC)[reply]
There were a lot of crashes in the history and many of them do not have its own Wikipedia article. If you take a look on other air crash articles, you will notice, that it is always mentioned in the lead section if, i.e., the crash was the dealiest in history, or in this country, or in this airline, or the only crash of this type of aircraft, etc. Daniel (talk) 18:30, 20 March 2016 (UTC)[reply]
No person is gonna read the first paragraph, where it says both plane and occupants disintegrated, and wonder, 'hey, why is this notable?', only to be enlightened by the revelation that this was the first Flydubai crash. 62.228.200.32 (talk) 19:09, 20 March 2016 (UTC)[reply]
We can't predict what influences the air crash would make on the airline and yet to give a conclusion. This might be the most notable thing we have about the airline so far. After knowing the causes, we could add more details to it. Let's just wait :-) --TerrainAhead ×TALK× 20:19, 20 March 2016 (UTC)[reply]
Fair enough, I guess. 62.228.200.32 (talk) 22:02, 20 March 2016 (UTC)[reply]

 Resolved I moved this information to the special sub-section about the airline. Daniel (talk) 15:40, 23 March 2016 (UTC)[reply]

Thanks! 128.0.208.243 (talk) 22:34, 23 March 2016 (UTC)[reply]

Flight path[edit]

Though the map was removed as a copyvio (the map layer was Google's), the last few moments of the flight can be mapped from public ADS-B data released by Flightradar24. 62.228.200.32 (talk) 22:05, 20 March 2016 (UTC)[reply]

  • I believe this data is not available for any use, even non-commercial. Can you link to the terms of use of their data? --Anthony Ivanoff (talk) 10:38, 23 March 2016 (UTC)[reply]
    • I'm not sure, but I'm having a bit of a hard time seeing how Flightradar24 might be able to claim copyright over the raw data output of a publicly-funded software publicly transmitted over radio waves. 93.109.172.116 (talk) 09:03, 28 March 2016 (UTC)[reply]

Better aircraft photo?[edit]

Searching through the commons and found 2 other photos of A6-FDN. These other photos show the 738 on final approach from an angle presenting the front of the aircraft, rather than the back. Are these better photos, or is the current one fine? A340swazzen (talk) 06:52, 21 March 2016 (UTC)[reply]

I think the current one is fine. Daniel (talk) 10:58, 21 March 2016 (UTC)[reply]
Shall we put a photo of the crash site in the information box and put the aircraft photo we have now by the description of the aircraft?--TerrainAhead ×TALK× 17:55, 21 March 2016 (UTC)[reply]
I do not think it's necessary. According to the template, the image provided in this infobox should be a "picture of the accident or incident or its aftermath, or, if involving a single aircraft, that aircraft". So this image is perfectly OK. Daniel (talk) 18:32, 21 March 2016 (UTC)[reply]
Agree You're right. The crash was so bad that the aircraft was totally smashed into small pieces :( Nobody is going to recognise the aircraft from those photos... --TerrainAhead ×TALK× 22:16, 21 March 2016 (UTC)[reply]

Similar accidents[edit]

Until the air accident investigation establish the definite cause of the crash, we can only speculate about similarity of this case with others. That is why I moved the link about another crash, provided by Petebutt from "See also" section here. As soon as the results of the investigation are announced, we can put those accidents, which had similar reasons with Flight FZ981, back to "See also" section. Feel free to add more cases to the list. The explanation of similarity would be helpful. Daniel (talk) 16:19, 23 March 2016 (UTC)[reply]

They are almost identical:- B737, bad weather, at night, go-around, impacting the ground at high velocity in a near vertical dive, no distress call. How more similar do you want them?--Petebutt (talk) 06:42, 24 March 2016 (UTC)[reply]
To User:Petebutt: I completely agree with you, that Flydubai Flight 981 and Tatarstan Airlines Flight 363 look not just similar, but virtually identical, judging by all unofficial information we have at the moment. But I would still be reluctant to create the "See also" section now. As you see, some editors on this talk page insisted that it was a pilot's suicide, and they may try to push the Germanwings case into that section, others insisted that it was a fire on board, or a missile, etc. So I suggest to wait for the preliminary results of the official investigation. It's a matter of some weeks, if not days, and then we can have a definite, comprehensive and most reliable answer about the cause of this crash. Daniel (talk) 11:56, 24 March 2016 (UTC)[reply]
Look again this case and when investigation end, Daniel - "some weeks" is very optimistic prognosis.* Tatarstan Airlines Flight 363 — Preceding unsigned comment added by 77.238.65.171 (talk) 13:10, 24 March 2016 (UTC)[reply]
@Petebutt:: Would you like, meanwhile, to do some clean-up in the Tatarstan Airlines Flight 363 article? I think, at the moment, it might be a little bit complicated for an average reader to comprehend all the details of that accident from the description which is provided there. I tried to write the lead section there now, but I'm not sure that I got all the details correctly. Daniel (talk) 02:23, 25 March 2016 (UTC)[reply]

You are right, according to the latest media reports, reportedly based on the information from the Flight 981 flight recorders, the circumstances of these two crashes were identical and I restore the "See also" section with the link to Tatarstan Airlines Flight 363. Thank you. Daniel (talk) 07:11, 26 March 2016 (UTC)[reply]

@Petebutt: Multiple media reports (1, 2, 3, 4, 5, etc.,) have pointed out to similarities between Boeing 737 Flight 981 and Flight 363 crashes, and you also insisted about this similarity above. However, Flight 981 was not mentioned in any of the two references, which you provided in your recent edit, claiming the similarities between Flight 981 crash and English Electric Canberra bomber crash in 1983 - it is your pure original research. Therefore it has no place in this article. And let me also note, that insulting your opponents, naming them "Putins puppets", is not appropriate for the Wikipedia discussion. - Daniel (talk) 03:15, 1 April 2016 (UTC)[reply]
I think you should speak to an administrator. Original research CASNNOT come from c redible sources. Youy have your knockers in a twist somewhere.--Petebutt (talk) 03:34, 1 April 2016 (UTC)[reply]
OK, I will follow your advice. - Daniel (talk) 03:39, 1 April 2016 (UTC)[reply]
Here I requested an administrator to resolve this dispute, as you suggested. - Daniel (talk) 05:37, 1 April 2016 (UTC)[reply]

There's not even been a preliminary report yet, so to say there have been many similar thrust-to-weight ratio incidents is pure speculation. The paragraph in question very clearly is OR and synthesis. 62.228.181.109 (talk) 10:35, 1 April 2016 (UTC)[reply]

This problem still persists. To say "In both cases, a Boeing 737 impacted the airfield at a high vertical speed while attempting a go-around." disregards the fact that these are two different generations of the 737.[2][3] The automation levels might be quite different, so we need an expert/qualified source to elaborate about differences and similarities regarding auto-trim, manual trim, elevator control etc.. The two given sources for this paragraph each mention only one type (737-500 and 737-800, respectively) and do not mention flight numbers, so where is the comparison to support the sentence "Aviation experts in Russia pointed out multiple similarities between Flight 981 and Tatarstan Airlines Flight 363."? I cannot read Russian, so I am not able to check the other sources (mentioned here) by myself. --Mopskatze (talk) 22:16, 15 January 2017 (UTC)[reply]

Trim Runaway?[edit]

Reference 42 is a good one, somewhat hard to interpret through translation (as I must) but upon manual control resumption, pressing the trim button would not result in a big transient because "trim" (the stabilizer tailplane bias position) is a slowly accumulating bias. Barring some mechanical failure, it can't move fast. We need to understand if there was an autotrim function active during the autopilot operation. If something failed there, then the trim could have "wound up" to a large nose down value due to a small persistent error. In a simple mechanical autopilot, that error could be a nervous pilot pushing or pulling back unconsciously all the time. Knowing if that was possible here requires understanding how the autotrim is implemented in this autopilot (and I don't) because another possibility would be that trim does not run at all when the AP is engaged.

If autotrim WERE engaged, and if the control servos are stronger than the pilot then trim runaway could build up a stabilizer bias position too large to be overcome by strength of manual input to the elevator. I say "stronger" because only moments before the loss of control the AP WAS successfully trimming the aircraft against what was almost surely the very same stabilizer trim (bias) offset, so we need some explanation why the pilots couldn't also overpower the offset.

Speculation: if shear caused a minor stall, and if the elevator authhority were only slightly greater than the trim, then recovery would be very slow. Markrkrebs (talk) 10:17, 26 March 2016 (UTC)[reply]

Thanks for linking the document. I read closely and didn't see anything alarming about STS: maybe you can clarify your concern? A few pages before that, is a discussion of stabilizer trim, including "control column actuated stabilizer trim cutout switches" which may be telling. To me that implies the autotrim does actuate the stabilizer, does respond to elevator trim and is particularly designed to notice and disengage if that trim load is coming from the control column. ...which seems like a very solid design. Note also that trim "hat" (the knupfel from the russian article) input automatically disengages the autopilot, another proper design element. These elements are intended to preclude trim runaway. The article you linked does seem to say they can be overridden, leaving a chance for pilot error. Anyway to summarize I do not understant your complaint about STS: it would have been pulling, too, because speed was high. Markrkrebs (talk) 10:46, 26 March 2016 (UTC)[reply]

Amplifying: "...does respond to elevator trim loads..." Markrkrebs (talk) 10:47, 26 March 2016 (UTC)[reply]

Lost your comment. Did I delete it by accident? Sorry. Please re-add your comment. Markrkrebs (talk) 11:03, 26 March 2016 (UTC)[reply]

References have changed so this discussion no longer refers to 42 but instead 29, by Kondrashov, discussing the tailplane setting and cockpit quote "pull up." Markrkrebs (talk) 11:31, 26 March 2016 (UTC)[reply]

'... with 5,000 hours being the minimum required for a captain at Flydubai'[edit]

This may not be the case with promotions and it might not have been the case when Sokratous was promoted. In general, promotions are offered according to seniority and staff shortage. The airline may have set a minimum number of hours for promotion to a captain or it may not have. If it did, we don't know what that number is. A job listing for a direct hire is not a valid source; and, I venture, it's probably where the newspaper got their info from as well. 93.109.172.116 (talk) 10:56, 26 March 2016 (UTC)[reply]

@93.109.172.116: 5,000 hours of total flying time is a minimum requirement for a captain's position in most of the major airlines. This piece of information is very important, as I have seen several media reports, which described Socratous as a "very experienced" captain. Capt. Sullenberger, who saved all the people on board in 2009 accident was described by media in the same words, as a "very experienced" captain. But he had logged 19,663 flight hours by the time of his accident. Even a first officer on the Sullenberger's plane had 15,643 flight hours, that is 2.6 times more than Capt.Socratous. Most of the readers are unaware of this and that is why I believe this piece of information is important, as it allows any reader to access the Socratous flying experinece more accurately. Daniel (talk) 12:23, 26 March 2016 (UTC)[reply]
No, it isn't 5,000 hours as a general rule. I don't see what Sullenberger has to do with anything, or what the reading public might be able to gather from it, either. If you've not got definitive evidence Sokratous was required to complete 5k hours, I'll be removing it again later. 93.109.172.116 (talk) 12:37, 26 March 2016 (UTC)[reply]
No, we didn't reach a consensus yet. Daniel (talk) 12:58, 26 March 2016 (UTC)[reply]
  • I support removing this info because it creates a wrong impression in a non-technical reader that the captain was somehow not skilled enough. --Anthony Ivanoff (talk) 12:25, 27 March 2016 (UTC)[reply]

 Resolved I withdraw my objections. Daniel (talk) 13:33, 27 March 2016 (UTC)[reply]

B737 Speed Trim System Bug[edit]

B737 Speed Trim System Bug was the reason for the crash of "Flydubai Flight 981" and "Tatarstan Airlines Flight 363". As I said to you Daniel, they test these systems in simulators, not in real field test. This bug act like a SUICIDE PILOT, when real pilots trying to 'pull up', it ill logic do exact opposite 'nose down' maneuver "to return the airplane to a trimmed speed" - this lead to continuously increasing negative angle of attack because GATHERING OF INFORMATION FROM REAL LIFE DEVICES is not like SIMULATION ONE. I think that the question "IS AUTOPILOT MUST TAKE CONTROL OVER PILOT IN EXTREME SITUATIONS LIKE STALL?" get its answer. — Preceding unsigned comment added by 77.238.65.171 (talk) 11:10, 26 March 2016 (UTC)[reply]

The case with Tatarstan Airlines Flight 363 is very interesting one. I need to investigate it further, but as I remember, the final report ruled that it was a pilot's error, as he never done a go-around in real life before (only in training), traces of alcohol was discovered in his blood, etc. But one expert in the commission filed a "minority report" ("a special opinion"), which is unheard of in any air crash investigation in Russia or USSR. His opinion was published in Russian, alongside the official report on IAC's website. I didn't examine it thoroughly yet, but as I remember, this expert blamed some intrinsic mechanical failure of one of Boeing 737 systems in this crash. This expert was a representative of Federal Air Transport Agency (Russian analogue of FAA) in the commission. Daniel (talk) 12:55, 26 March 2016 (UTC)[reply]
This will be Daniel huge scandal for Boeing and I have no doubt that they will try to cover it up. I hope that they have enough brain to realize, however, that if it happened again - someone will start asking questions. I have already started to harass AAIB - they will not withstand pressure if their competence is questioned. For years, there are disputes on whether to allow the autopilot to control planes in critical situations or not. Biggest manufacturers such as Boeing and Airbus trying surreptitiously to put pilot control under control by "semi-autopilot" systems like this STS and Airbus's Fly-by-wire. Thus, they make flights considerably more dangerous than PURE autopilot or manually control planes, because PILOTS ARE NOT FULLY AWARE WHAT EXACTLY IS THEIR CONTROL OVER AIRCRAFT and therefore are not fully aware of actions they can take in critical situations. I'm sure that the pilots of Flight 981 and Flight 363 are fully surprised when they do 'pull up' action and plane go down instead. In those 40 seconds, I doubt whether engineers who has created these systems would have guessed what was happening and how to get out of the situation in this short interval. Sometimes I'm surprised how the media use phrases "very experience", "not experience" if it has any relevance in these cases where the plane do what it should not and pilots knowledge are not matter at all - because what he must know is known only by few people in the world. The work of these systems is a well-kept secret. You can not find more than a few lines of information about them - basically superficial such. You take complex decisions in critical situations with minimum information - I do not know what an experienced pilot you must to be - to be able to handle it. Most worst, after such incidents - they take a few pilots and inserted them in such a hopeless situation in SIMULATOR and of course, most of them fail - a fraction manage to cope because of fraud (for example, some instructor give them seemingly insignificant additional information)and in END: Blame ALWAYS pilots because such technical illiteracy is widespread among them that companies need to punish them as they cut wages and make pointless courses to "increase" their professionalism.
The scenario is repeated every time in the same way:
Flight 363
"regular violation of the crew members worlk-rest regime and vacation liability that could result in chronic-fatigue build and negatively effect the crew members performance;"
Flight 981
"Pilots ‘worked to death’: Flydubai whistleblower says fatigue-related crash predicted"
Of course, such "whistleblowers" are the same people that on the end write final reports. It would be funny if it were not tragic.— Preceding unsigned comment added by 77.238.65.171 (talk) 14:09, 26 March 2016 (UTC)[reply]

Full Russia-1 TV news report[edit]

For those Wikipedians, who do not speak Russian, here is a more detailed account of this TV report. I agree, that not all this information should end up in the article's body, but it might be useful for the editors of this article.

According to Russia-1 TV news report of 25 March, citing an undisclosed source in the air crash investigation commission, the CVR and FDR flight recordings revealed the following sequence of events. At 3:40:00 the captain made a decision to abort a second landing attempt, due to severe weather conditions, and to climb to flight level 50 (5,000 feet (1,500 m)). For the next 40 seconds the aircraft was climbing up, in the autopilot regime, with a 15 degrees angle. Before the aircraft reached the designated flight level, the captain disengaged the autopilot. Right after that, the aircraft began the nosedive.

It is unclear yet, why the captain decided to disable the autopilot, but according to one suggestion, the aircraft may have experienced the wind shear at that moment and the captain decided to manually level the aircraft. The moment the autopilot was disconnected, the tailplane, for some reason, has turned into a nosedive position. According to one suggestion, during turbulence, when the captain was cutting off the autopilot, he accidentally pressed the tailplane thumb controller, without realizing it. Another possibility is that the tailplane went into the nosedive position because of some unknown mechanical malfunction in Boeing 737.

The CVR, reportedly, recorded the following final words of the flight crew:
3:40:40 Don't worry, don't worry, don't worry.
3:40:45 Don't do that, don't do that, don't do that!
3:40:50 Pull up! Pull up! Pull up!

The pilots were pulling the aircraft's control columns, trying to level the aircraft with the help of elevators, without realizing that their efforts are futile, as the problem was caused by the wrong tailplane position.

For the last six seconds of the aircraft's dive (3:40:54-3:41:00), all that can be heard are "inhuman screams," the channel's source said. At 3:41:00 the aircraft impacted the ground.

The Interstate Aviation Committee didn't make any comments, regarding the information presented in the Russia-1 TV report. Daniel (talk) 16:30, 26 March 2016 (UTC)[reply]

"According to one suggestion, during turbulence, when the captain was cutting off the autopilot, he accidentally pressed the tailplane thumb controller, without realizing it." According to other suggestion there was little probability two pilots of two different plane in almost the same circumstances to pressed the tailplane thumb controller accidentally.
Stabilizer
The horizontal stabilizer is positioned by a single electric trim motor controlled through either the stab trim switches on the control wheel or autopilot trim. The stabilizer may also be positioned by manually rotating the stabilizer trim wheel.
http://www.737ng.co.uk/B_NG-Flight_Controls.pdf
Stab Trim Switches
http://www.flaps2approach.com/journal/tag/b737-300-throttle-quadrant
For example look where these switches are and how someone can activate them accidentally. And most important the activation of Stab Trim Switches is registered by FDR.
https://img.planespotters.net/photo/230000/original/n73283-united-airlines-boeing-737-824wl_PlanespottersNet_230834.jpg

<<but, touching those trim switches even momentarily reverts control back to the pilots, and their operation makes only slow, incremental change to the stabilizer position. That means that touching it shouldn't be ABLE to create a large offset quickly. There has been some interpretation, which stands in the main article discussion, that the tailplane moved immediately to full down position. That's incredible, and I don't think was stated that way in the original article (though I had to read a translation.) - mark>>

P.s. As I told you Daniel, they have already started a campaign aimed to discredit pilots and blame them for this accident. How you think, is it very easy to get CVR data in such investigation? I can tell you, for example, that if some investigator spreed this information - he may pay for that with his life literally. A lawsuit against Boeing can cost BILLION to the company. No one inside can afford such thing without permission and access to this information is highly limited. They themselves spreed it to prepare society for their lies. — Preceding unsigned comment added by 77.238.65.171 (talk), Today

Wikipedia article mentioned in media[edit]

This Wikipedia article was mentioned in the low-profile Russian-language news reports (1, 2), reporting about a conspiracy theory of one blogger, that the crash in Rostov didn't actually happen. As a proof, this guy pointed also on the fact, that Wikipedia article about the crash appeared online three hours after the accident: "How can you write an article only three hours after the tragedy?", he says. Daniel (talk) 15:00, 27 March 2016 (UTC)[reply]

Well, that's amusing! ...and sad. 93.109.172.116 (talk) 15:17, 27 March 2016 (UTC)[reply]
"How can you write an article only three hours after the tragedy?" :-))) No,I read somewhere that this article was write BEFORE crash, but when "he" or "they" realizing their error about Time Zone, feeling embarrassed by their stupidity, they change version as "only three hours". 77.238.65.171 (talk) 17:11, 27 March 2016 (UTC)[reply]

While 'trying to switch off the autopilot'[edit]

Could you point me to where this connection was made in the Russian report? 93.109.172.116 (talk) 15:49, 27 March 2016 (UTC)[reply]

Here is the text of the original TV report: "Почему включился в режим пике стабилизатор — вопрос. Он приводится в действие кнопкой, которую пилоты называют "кнюпель". То есть во время турбулентности командир, переходя в ручной режим, мог случайно зацепить этот кнюпель, и не заметил". Do you know Russian? - Daniel (talk) 16:27, 27 March 2016 (UTC)[reply]
No, I do not. But I was hoping I could get the gist of it 'cause a lot appears to have been lost in translation. Thanks. 93.109.172.116 (talk) 18:43, 27 March 2016 (UTC)[reply]
I'll try to translate it as close to the source, as possible: Why the stabiliser switched to the dive mode is the question. It is activated by a button, which the pilots call a "knüppel". So during the turbulence the captain, going into the manual mode, may have accidentally hooked this knüppel and did not notice it. - Daniel (talk) 20:52, 27 March 2016 (UTC)[reply]
Thank you. 93.109.172.116 (talk) 08:54, 28 March 2016 (UTC)[reply]

This button makes the stabilizer move only slowly, AND using it at all, however briefly, instantly disconnects the autopilot. So, the pilot may well have pushed the button, but it would then have returned control immediately to him. There is no good reason to expect the "stabilizer switched to dive mode" at a transition to manual control: again, it does not move quickly. There appear to be ways the pilots could override trim "windup" protections, but "accidentally hooked the knuppel" doesn't really make sense. Probably we will find a trim windup from some source, then a panic-driven stall, however minor, at the handover, then with the trim all the way down, the only incremental pitch up authority available from the elevator could not quickly enough recover the attitude. Markrkrebs (talk) 22:49, 29 March 2016 (UTC)[reply]

In response to this translation:
"Why the stabiliser switched to the dive mode is the question. It is activated by a button, which the pilots call a "knüppel". So during the turbulence the captain, going into the manual mode, may have accidentally hooked this knüppel and did not notice it."
Totally nonsensical.
The Horizontal Stabilizer does not have a "dive" mode, or any other "modes" for that matter. Neither is there any "button" that switches the HS into or out of any such a non-existence "modes." There is only the allowable range of up or down travel, which is more limited when the AP does the trimming. Additionally, the AP HS trim speed is much slower than the trim speed available to the pilots, when flying manually.
Each pilot has double (side-by-side) HS trim switches on his own control yoke. They are recessed within a guard, so that they cannot be activated inadvertently. Each switch is connected to one of the two HS Brake systems. When both are activated in the same (Up or Down) direction, both HS brakes are released and power is connected to the HS drive motor. If the switches are activated in the opposite directions at the same time, OR IF one pilot tries to activate his switches DOWN, while the other pilot tries to activate his switches UP, then the HS brakes will not release and power to the electric drive jackscrew will be cut off, until the situation is no longer contradictory.
If the pilot is flying manually, he will continue to "pickle" the TWO UP or DOWN switches (in unison) on his control column, as the speed of the plane changes, to keep the pitch axis "in trim," so that he doesn't have to fight the pitch control. Whenever he has trimmed it correctly, he can let go of the yoke and the plane's pitch won't change, until the speed changes again.
An additional protection against the possibility of a "runaway" HS trim, is that any Control Column movement opposing the direction that the trim system is operating, will activate a Trim Cutout switch and that will stop operation of the main electric and AP trim system.
A single channel failure of the HS trim system, illuminates the SPEED TRIM FAIL Light on the Master Caution panel, which can be extinguished by pushing that light. If that light indicates a dual channel failure, the light cannot be extinguished.
The AP disconnect switch (a round button) is located on the inside of the left or right yoke, and well below the guarded HS Stab dual trim switches. The pilot flying the plane manually, normally rests his thumb on the extended module that contains the AP disconnect switch. It is inconceivable that a pilot could "accidentally" move the HS Stab, in an UP or DOWN direction, when he really intended to disconnect the AP by pushing the single round button, that is located on the inside of his yoke and further down.
There are TWO HS Stab Trim cutoff switches on the center pedestal. Should the AP start trimming one way or the other, without being commanded to do so by pilot inputs to the AP command panel on the glare shield, the pilots can immediately activate those two HS cutoff switches. They would be aware of ANY movement of the HS, because each pilot has a large wheel on his side of the pedestal that turns forward or backward, as the HS Stab moves. If they are forced to shut off all power to the HS trim system, they can trim it manually with those HS trim wheels. EditorASC (talk) 09:06, 3 April 2016 (UTC)[reply]
Mr.Boser, thank you for this detailed explanation. If this reason is unlikely, what you believe could be a more likely scenario of this crash? - Daniel (talk) 10:24, 3 April 2016 (UTC)[reply]
Thanks for letting me know that additional information might be helpful to other editors. My purpose was not to try and speculate as to a cause of the accident. Many possibilities remain and it is not uncommon for the official investigation to discover a combination of related factors, in the causal chain of events, that finally led to the accident. We don't know at this stage, because the ongoing investigation has not even issued a prelim report, much less a final one.
Unfortunately, it is all too common for the highly competitive Media to engage in all kinds of wild and irresponsible speculations, because the most outrageous headlines are usually the ones that sell the most papers, or garner the highest TV news ratings. Most of those very early speculations turn out to be not only wrong, but also tend to be loaded with statements revealing incredible ignorance about aviation nomenclature, systems and processes. Thus, it is better policy to wait until some official reports have been issued, before relying upon "reliable" sources to back up allegedly factual early statements made by the sensationalist media.
I have repeatedly cautioned in various other Wiki accident talk pages, that so-called "reliable" sources routinely accepted as WP:RS for other subjects, are frequently unreliable in situations like this.
For instance, the Chicago Tribune actually published a story shortly after the 1991 crash of a UAL 737 near Colorado Springs, Colorado, which included an allegation that a shockwave from the explosion hurled a young child across the room in her apartment, slamming her against a wall. That never happened, because there was no explosion and thus no shockwave. In fact, no windows were broken in an apartment building that was only a few hundred feet away from the impact crater, which would not have been the case if there had been an explosion generating a powerful shockwave. That kind of irresponsible and deliberately false information has been reported time and again by sources that are routinely accepted as WP:RS for many other subjects.
In short, all wiki editors should carefully assess early "factual" statements from all kinds of media -- which might imply causality -- to see if they are contradictory to common sense logic and/or how airplane systems and pilot SOPs normally operate. Don't rush to parrot irresponsible ravings of the media, just because the source is normally accepted as WP:RS for other subjects. EditorASC (talk) 18:02, 3 April 2016 (UTC)[reply]

New leak[edit]

See [4], though maybe we should wait before adding it to the article. 93.109.172.116 (talk) 09:56, 28 March 2016 (UTC)[reply]

I've seen it this morning. The original Kommersant article is here. The author of this article cited an unnamed source "close to investigation", but didn't state that his source was actually a member of the IAC's investigation team, as was specifically mentioned in the Russia-1 TV report, refering to their source. In effect, he is contradicting the Russia-1 TV report, saying that the climb after the second aborted landing was done by the flying pilot, not on autopilot. According to Kommersant, during a climb a pilot pulled the control stick up too much, causing a stall break and an uncontrollable nosedive. They say, their version explains the words from the CVR, which were revealed earlier in the Russia-1 TV report: "don't worry", "don't do that" and "pull up". According to Kommersant, the second pilot realised the stall danger and attempted to prevent it by pushing his own control column to bring the Boeing’s nose down, while the flying pilot was yelling at his colleague not to do it. This article does not provide any new factual information, as was in the case of Russia-1 TV report. It merely tries to explain the words on the CVR, even without a claim that this information is coming from the member of the investigation team. So I would consider it a pure speculation and agree that we should wait for the information from the IAC. - Daniel (talk) 10:55, 28 March 2016 (UTC)[reply]
unnamed source "close to investigation" - mean that IAC is started to spread rumors. Before time I have complain in European Commission asking them to start an investigation against Bureau of Enquiry and Analysis for Civil Aviation Safety because internal "unnamed source close to investigation" has released information to the media before they made a statement or report - something they have no right to do. "Unnamed source close to investigation" quickly became officially BEA to not start lawsuit against them. These informal and illegal statements are Statistical Survey refining their lies in advance. In simple words WHAT IAC SAY CAN NOT BE BRING BACK, THEREFORE THEY FIRST PLACE THEIR UNOFFICIAL LIES IN THE MOUTH OF "UNNAMED SOURCE CLOSE TO INVESTIGATION", THEN CHECK WHAT WILL BE THE RESPOND, BEFORE OFFICIAL STATEMENT. And such SEVERE STALL SITUATION WAS NEVER COME ON FLIGHT 981, this can easily be demonstrated even with data from FlightRadar24, and such lie can not be easy push to the media by IAC because this will be bring number of FDR DATA REQUESTS. Don't buy it. Cheap sensationalism. Boeing will eat the DICK this time - and there will be not salvation for them while not admitting their guilt. 77.238.65.171 (talk) 11:20, 28 March 2016 (UTC)[reply]
Two versions are contradicting each other. It looks like, Russia-1 TV report was a genuine leak from IAC, while the article in Kommersant is what you called "sensationalism", judging by the style it was written, and has nothing to do with IAC. - Daniel (talk) 12:12, 28 March 2016 (UTC)[reply]

Sorry, can you clarify whether you judge the report of large down stabilizer trim to be accurate? (It would be hard to create that during a protracted, over-aggressive climb. The trim would naturally go the other way.) Markrkrebs (talk) 22:52, 29 March 2016 (UTC)[reply]

We can only speculate about the accuracy of any version at the moment. But I noted some details about this TV report:
1. Russia-1 is a state-owned TV channel.
2. Reporter said that their source is a member of the IAC investigation team, but insisted that information in their report is not "official", and only information publicly released by IAC should be considered as accurate.
3. For the first time in media reports, they provided the exact timing of the events - 03:40:00 as a start of go-around, 03:40:40 as a start of descent and 03:41:00 as a time of crash.
4. For the first time in media reports, they provided the exact words from the CVR ("don't worry", "don't do that" and "pull up"), although they didn't provide the original English words, instead they re-enacted the dialogue in Russian.
5. They also mentioned, that the last six seconds on CVR were just "inhumane screams" in the cockpit (as I remember, on the video of a go-around, the plane was hidden in the clouds. Could they started to scream the moment the clouds are gone an they began to see the city lights just in front of them?- this is my personal guess)
6. No previous report claimed that its information is based on the flight recorder data.
7. There were no previous media reports that horizontal stabiliser could have anything to do with the crash.
8. They presented a main version, that pilot accidentally activated this trimming device, but they also mentioned a possibility that it might be some "unprecedented" mechanical failure in Boeing 737.
9. When next day the IAC representative was asked to comment on this report, he just noted that the cockpit dialogue was re-enacted by actors, but refused to provide any further comments.
Of course, it can turn out to be just another journalist speculation. But from all the media reports, which I read or heard so far, that one seemed to be the most reliable. - Daniel (talk) 00:06, 30 March 2016 (UTC)[reply]

Thank you for providing the reference to the original Kommersant article. I read a translation but can't expand much. There is a lot of discussion of trim (mis-translated as "liner") and stall, a surprise if so, since speed was growing. Markrkrebs (talk) 03:05, 31 March 2016 (UTC)[reply]

I've seen your assessment of the Komersant article as dubious, but everything in there sounds very credible to me. In particular, the high pitch up moment consequence of stowing flaps. When flaps are down, a large compensatory up trim is required and when they are stowed, down trim will be required. One imagines ice impeding the elevator input, a "windup" of down trim, then the controls breaking free & sudden pitch down. Certainly I'm in the weeds correlating mere snippets of data, but the IAC statement of control column input AND trim motion in the same direction is a strong hint. The statement at the end of the article that pilots found TOGA too challenging does seem inflammatory. I bet the pilots wouldn't agree with that characterization. I'll try to research 737 TOGA complaints a bit. Markrkrebs (talk) 11:43, 14 April 2016 (UTC)[reply]

'Investigators from the Russian Investigative Committee participate in all actions of the IAC investigation. If IAC finds somebody to blame- RIC will prosecute them, according to law'[edit]

In what way do they participate? The IAC does not look for people to 'blame' - that's a gross misunderstanding of the purpose of an air accident investigation. 93.109.172.116 (talk) 21:49, 28 March 2016 (UTC)[reply]

Investigators from the Investigative Committee of Russia (I abbreviate it to ICR) accompany the IAC experts in all their investigative actions. The ICR representatives participate in the meetings of the IAC. They will also sign the final report of the IAC investigation. If the IAC commission in its evaluation of the actions of the ATC, meteorological services or any other staff members, will find any negligence, the ICR will prosecute those people according to the law. - Daniel (talk) 22:17, 28 March 2016 (UTC)[reply]
Do you have a source for any of this? I fail to see why federal investigators would be meddling in the safety investigation. I've skimmed the Tatarstan crash report and there appears to be a solitary mention of the ICR on p. 12; if I'm understanding it correctly, the ICR conducted some sort of preliminary investigation, but they don't even bother to say what their findings were. 93.109.172.116 (talk) 00:06, 29 March 2016 (UTC)[reply]
Look even on the protocol of the IAC Commission final meeting for the case you just mentioned. Mr.Nikiktin (Никитин А.А.) on the list of the participants - is a representative of the ICR (представитель СК РФ)!!! Why do you think, that other editors have "gross misunderstanding" of the things, they write about??? Do you really believe that being a pilot from Cyprus makes you a great expert in the air crash investigation process in Russia? Let me work on this article, trying to improve it, instead of wasting time, counter-acting your accusations that I have "gross misunderstanding" in the air crash investigation process. - Daniel (talk) 03:17, 29 March 2016 (UTC)[reply]
The air crash investigation process in Russia closely follows ICAO Annex 13, as in every other country. The purpose of such investigations is to determine the causes and contributing factors that led to an accident and to make recommendations that look to improve aviation safety. The purpose of such investigations is not to apportion 'blame'; no, investigators examine individual and organisational failings within a wider safety framework. If the ICR are involved in anything but observer capacity, where no foul play is suspected, that is something that needs to be explicitly stated. 87.228.158.48 (talk) 10:06, 29 March 2016 (UTC)[reply]

Proposal to delete section "4.3 Russian TV leak"[edit]

The link #28 is entirely in Russian, while link #40 is already dead and link #41 is from the NYTimes: [5], which contains the following, unmitigated garbage reporting:

"The television channel cited experts who suggested that by turning off the autopilot, the pilots were trying to pull the plane back to a horizontal position. But at that moment a stabilizing fin at the jet’s tail was switched on.

With the fin activated, “the elevator is no longer working and the plane practically does not react to the pilot’s control panel,” the report said. The channel suggested that the pilot could have accidentally hit the button that activated the fin because of his reported “chronic fatigue.”

It is bad enough that we allow statements "supported" with claims to having heard anonymous leaks, but when such is combined with idiotic, know-nothing reporting like that, then Wikipedia has reduced itself to little more than sensationalist tabloid journalism. How on earth can anyone suggest that this amounts to compliance with WP:RS and NPOV and no OR standards? I suggest deleting the entire section. It amounts to utter garbage. EditorASC (talk) 07:14, 4 April 2016 (UTC)[reply]

Control Column Input[edit]

The IAC report cites simultaneous control column input and 5 deg Stab. trim down. If they said that accurately, the pilots or a pilot *did it* Putting in control down or severe systems failure (disavowed elsewhere) would be required to get 1g down acceleration, an extreme maneuver not caused by something like stall or wind shear.

I saw one accident with sudden negative g: a goose hit the stabilizer of a (*much* smaller) airplane, tearing away half the stabilizer. If a physical mechanism failed, there are modes that could induce a negative g, but "control column input" means human action, and that is something that's measured, and they haven't released the last seconds of CVR... Maybe there was an argument, and the suicidal guy was stronger. Markrkrebs (talk) 11:23, 14 April 2016 (UTC)[reply]

Correct me if I am wrong, but control column nose down input affects the elevators, not the stabilizer trim. The way I understand the indicated source, it reports two simultaneous events, not a "cause and effect":
  • Control column nose-down input (affects the elevators)
  • 5 degree horizontal stabilizer trim down (has nothing to do with yoke nose down input)
I changed the article text to be closer to the indicated source. By the way, the report is in both English and Russian, so I propose we link to the English version and not the Russian one. Rentzepopoulos (talk) 17:05, 15 April 2016 (UTC)[reply]

Good choice to match the language of the source report. I don't agree that trim and yoke are unrelated. The general operation of the stabilizer trim is to actuate slowly under manual command input. That may seem unrelated but are coupled by the physics. Either pilot input or automatic trim functions may run the stabilizer in response to input pressure on the control column. Stowing gear and flaps after approach would have a certain consequence of nose up pitching moment, requiring lots of control yoke force, and nose down stabilizer trim to compensate for it. So the two inputs are related. At issue is how the two parts, both correct inputs could manifest as a massive overreaction. The illusion of not making the pitchover has been suggested. That's a real thing but the pilots should have been looking at the gyros and airspeed too; seems an unlikely mistake. Furthermore -1g is the new data, and it is an extraordinary report, exceeding any input a pilot would make, ever. A zero g pitchover would be the most extreme and effective input one should attempt, fearing imminent stall at high pitch, AND that would absolutely prevent stall. So from the information given it appears the aircraft likely did not stall (something easy enough to state, so it's disturbing that they didn't) and IF not, then it should be easily recoverable. Markrkrebs (talk) 12:25, 17 April 2016 (UTC)[reply]

This is besides the point. What I said was not that elevators and the stabilizer trim are unrelated in terms of aircraft control. What I said is that the report was not accurately reflected in the previous text and that for this reason I changed it to be closer to the report. What you write may be correct or not -- I am not a pilot, nor an air incident investigator to have an expert opinion on the subject. However, Wikipedia policy about original research does not support writing our understanding on the article subject; instead, it expects writing as neutrally as possible what is backed by reliable sources. Rentzepopoulos (talk) 23:41, 17 April 2016 (UTC)[reply]

Yes I agree I'm unable not to think of this as a puzzle, and we will learn more when the report comes out & I hope it will be definitive. There seem to be many loose ends. 98.245.115.148 (talk) 12:56, 18 April 2016 (UTC)[reply]

I have now reviewed the full IAC report. It contains one especially useful graphic showing trim command, yoke inputs, speed, altitude and pitch. These data suggest the TOGA phase was flown with only a few trim inputs. The report suggests the pilots may have assumed (as many do) that TOGA is an autopilot mode, when in fact there is only flight director guidance and throttle increase. Whether by mistake or inattention, the pilot allowed pitch to grow too high, and speed too low during the climbout. This was a significant pilot error. A sufficient response was provided with additional down trim. There was simultaneous down elevator, but not clear whether that was "flown" or a controls-free response to the trim input. The text seemed to say so, but this area of the translation was too garbled for me to be sure. The pitch rate was a roughly steady -5 deg/second, which would have been felt in the aircraft as reduction of perceived load factor to 1/2 g. As the speed increased, this unweighting proceeded to around zero g. With pitch, flight director, g-loading and speed indications showing a dive, the underspeed recovery was complete and, up elevator was clearly called for but not provided. The report hypothesizes the pilot was disoriented by the situation. At zero and -20 pitch, brief pitch up inputs were provided on the stabilizer trim, and one elevator, but quickly countermanded in both cases. I could not read the report with certainty but it seems the copilot was in disagreement with the pilot flying, and may have input these two trim changes. Markrkrebs (talk) 19:51, 18 April 2016 (UTC)[reply]

Also it is pretty easy to be sure the aircraft did not stall. With the large negative pitch rate the Normal acceleration Nz would be much reduced to attainable levels, despite the very low speed. So there would have been no loss of control, just a tragic sequence of bad inputs, probably from disorientation. There is a surprising paucity of data in the report, but there is enough to seemingly put this to bed. Markrkrebs (talk) 01:06, 19 April 2016 (UTC)[reply]

To editor Markrkrebs: By the "full IAC report" do you mean the IAC statement of 8 April? - Daniel (talk) 17:48, 19 April 2016 (UTC)[reply]

No, one of the long Russian language reports. It was 250+ pages... Markrkrebs (talk) 00:05, 20 April 2016 (UTC)[reply]

To editor Markrkrebs: 250+ pages report about Flydubai Flight 981?! Could you provide a link to this report? - Daniel (talk) 02:46, 20 April 2016 (UTC)[reply]

I will try to find the article again: should be in the browser "history" file on another computer. Meanwhile I'll link the graph. https://upload.wikimedia.org/wikipedia/commons/3/30/IAC_plot_fdb981_mishap.png Markrkrebs (talk) 10:50, 20 April 2016 (UTC)[reply]

Here is a link to the report I downloaded yesterday. I will look for the original link if this is not sufficient. https://drive.google.com/a/google.com/file/d/0B3y144tPeBygOHJSQk93WVcwWXc/view?usp=drivesdk Markrkrebs (talk) 11:23, 20 April 2016 (UTC)[reply]

Hmm, I think I got the two flights mixed up, the report is from Tartarstan 363, & not relevant to this flight. Markrkrebs (talk) 11:46, 20 April 2016 (UTC)[reply]

Both the nose down input, by moving the control yoke forward, AND the trimming of the Hor Stab to 5 degrees nose down (simultaneously) could only have happened as a result of one or both pilots deliberately doing that. It couldn't have happened as a result of some "automatic" flight computer command. To me, that is an indication of an incompetent pilot (poorly, or not adequately trained).
Properly trained pilots would know that if you trim the Hor Stab to full nose down, that the plane will immediately go into a high speed dive, and unless there is a lot of altitude left, recovery will be impossible. That is because the elevators do not have enough remaining pitch control authority on their own, if the HS is trimmed to such an extreme nose down position. Thus, merely pulling back as hard as possible on the yoke, once the dive has commenced, will not pull the nose back up to any significant degree. Additionally, the HS CANNOT be trimmed back to a level, or slightly nose up flight position, so long as the pilots are pulling back as hard as they can on the yoke. That is because such action will stall the HS jack screws and they will not be able to trim the HS the other direction, until the pilots release their pressure on the yoke.
In other words, they have to stop pulling back on the yoke, before the HS will be able to trim back to a positive pitch angle. Well-trained pilots know this and they would never have allowed this kind of un-recoverable trim situation to develop in the first place. The fatal error was in trimming the HS so far to a nose down position. Once that happened, at an altitude of only about 3,000 ft., their fate was sealed.
Several studies were carried out by NASA and Boeing, after the inflight upset and crash of NWA flight 705, a B-720B, in the Florida Everglades on Feb. 12, 1963, because the investigation had revealed the pilot had tried to prevent an immenent stall (because of extreme updrafts encountered after the plane had inadvertently entered the area of a T-Storm Squall Line) by using BOTH full nose down HS trim and full nose down elevator authority at the same time:
Statement from the official CAB accident report on that crash:
"During the dive the pilot undoubtedly attempted to retrim the stabilizer in the aircraft noseup direction, but these attempts were unsuccessful because the high down elevator loads had by that time stalled the stabilizer electric drive motor, preventing system operation by the pilot control column trim switches."
Jet upset training has come a long way since those days. All competent pilots now know that maintaining proper attitude, is more important than maintaining a specified altitude, when turbulent conditions make it difficult or impossible to do both at the same time. Thus, using extreme pitch trim is one of the most verboten actions of all. With this accident, we are once again reminded why. EditorASC (talk) 12:21, 20 April 2016 (UTC)[reply]

It's really strong & ominous point about Stab. trim being unable to work against full elevator. Is that still true for the 737? 98.245.115.148 (talk) 18:45, 20 April 2016 (UTC)[reply]

It is true for all jet aircraft with trimable horizontal stabilizers. When the elevator is held in the extreme opposite position of the trim being demanded by the pilot for the HS, then it imposes an enormous ft. lbs. load against the efforts of the jackscrew motor, which is trying to do the opposite of what the elevator is trying to do.
That is why all jet upset training, which is required for all jet airliner pilots, emphasizes the extreme danger of using extreme HS trim as a means of recovering from an inflight upset. Years ago, a UAL 727 Capt. flew through the boundary line of two conflicting frontal systems. He encountered an enormous up-draft which the FDR showed to be similar to the initial one that hit NWA flt 705, and that UAL 727 Capt responded the same way. He tried so hard to maintain his assigned altitude that the plane was forced into a dive from above 20,000 ft. (I don't remember the precise FL at which the plane was cruising when the upset happened), −because he violated his training and used extreme AND (aircraft nose down) HS trim to overcome the enormous updraft he encountered. He finally pulled the plane out of the dive at around 5,000 ft. AGL and then went back up to another extreme pitchup attitude, that almost resulted in a repeat scenario. All UAL pilots were sent an emergency bulletin describing in great detail, what happened to that plane and why it happened: Because the Capt ignored his jet upset training about the extreme risk of using extreme HS trim, to try and maintain an assigned altitude, INSTEAD of a normal and safe ATTITUDE.
One night I was flying a 727 over Wyoming and encountered extreme mountain wave. I was forced to retard the thrust levers to idle, to prevent an overspeed condition and shortly after that to use METO power to avoid a too low speed. Notified ATC that we were unable to maintain assigned altitude because of extreme mtn. wave activity. I followed my upset training and maintained proper ATTITUDE, and let the altitude do whatever it had to do, to keep the plane level. When I finally got out of that area, our altitude had fluctuated by more than 5,000 ft, but that kept the plane in a level attitude. I did not resort to HS trim at all; used only elevator and eng thrust to keep the plane within the safe speed range and proper attitude. That is how all competent pilots are trained, and the reason why jet upsets are almost never heard of nowadays, while they had several of them in the early days of the jet airliner replacing the older piston-driven planes. EditorASC (talk) 22:00, 20 April 2016 (UTC)[reply]

somebody asked about the goose impact reference. Here it is: https://www.asias.faa.gov/apex/f?p=100:17:::NO::AP_BRIEF_RPT_VAR:CHI08FA027 Markrkrebs (talk) 11:27, 6 November 2021 (UTC)[reply]

Interim report[edit]

An interim report has been released by the MAK. Mjroots (talk) 21:31, 20 April 2016 (UTC)[reply]

External links modified[edit]

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External links modified[edit]

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Reexamination of accident cause in light of similar 737 accidents[edit]

The high speed, hard nose down terminal event of this accident is similar to MCAS related Lion Air and Ethiopian Air accidents. While models are different and software was theoretically not installed, it is not uncommon to release software with disabled sections of code. While the sensory illusion cause is plausible, it does not explain the hard forward control input immediately prior the the accident, as the illusion generally causes inattentive pilots to slowly correct perceived flight attitude problems. — Preceding unsigned comment added by 137.3.122.55 (talk) 16:47, 4 April 2019 (UTC)[reply]

Do you have a reliable source that links it to the MAX accidents, it was not a MAX and doesnt have MCAS. MilborneOne (talk) 18:08, 4 April 2019 (UTC)[reply]
"...it is not uncommon to release software with disabled sections of code. While the sensory illusion cause is plausible, it does not explain the hard forward control input immediately prior to the accident, as the illusion generally causes inattentive pilots to slowly correct perceived flight attitude problems."
That is a pure OR speculation statement. There are no other accidents in airliner history which can support that kind of a hypothetical for any airliner, other than the 737 MAX planes, but there have been accidents and near accidents that were caused by a pilot deliberately trimming the HS to the full AND position, either because he ignored his jet upset training, or because he was never properly trained in the first place.EditorASC (talk) 20:48, 20 April 2019 (UTC)[reply]
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