Talk:Ethiopian Airlines Flight 302

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MAX 8 emergency landing in Orlando today[edit]

De Telegraaf is reporting that a MAX 8 made an emergency landing in Orlando today whilst being flown to storage in the Mojave Desert. Is this worth mentioning either here, or at the aircraft's article? Mjroots (talk) 21:43, 26 March 2019 (UTC)

The aircraft article as it clearly has no bearing on this article at all, although the RS is saying "According to the American aircraft authority, the incident has nothing to do with the two previous accidents." so perhaps nowhere, and we should stop looking for sensation. The Rambling Man (talk) 22:13, 26 March 2019 (UTC)
Agree that it shouldn't be included. This incident has little to do with Boeing, as it is appears to be an engine-related event. Per anti-trust laws, Boeing is not allowed to manufacture engines for their planes. Boeing customers have a choice of engine manufactures when they purchase planes (GE, Roles Royce, etc.). 凰兰时罗 (talk) 00:50, 27 March 2019 (UTC)

AHEM: boeing customers on 737 have NO CHOICE of engine, as per bs "anti-trust" law, they are allowed to monopoly with GE for both 737 and 777. shaking my damn head i must specify this. i am beyond flabbergasted at this ridiculous crash and what it means for the state of art of engineering at boeing. yikes. how many less critical softwares are bad at boeing?. I would like to add i don't know of ANY law saying aircraft can't be made by same company engines included. you are spreading misinformation, the reason boeing doesn't make engines is because they literally can't, thanks. — Preceding unsigned comment added by 24.255.48.61 (talk) 09:43, 28 March 2019 (UTC)

I don't think it's BS. Rather, it's a key part of Boeing history. Here is a brief account. Moreover, after these anti-trust decisions, Boeing family sold all their stock of Boeing company in protest. A deeper research can produce all the key details, dates, etc, but since it's off topic here, let's leave it at this. 凰兰时罗 (talk) 14:58, 28 March 2019 (UTC)
AFAIK the engines fitted to the 737 Max are the only ones available in the required thrust range, the other engine manufacturers P&W and RR not having a suitable alternative engine available, most of their high-bypass turbofan engines being too large for the 737. — Preceding unsigned comment added by 95.149.172.230 (talk) 09:27, 29 March 2019 (UTC)
This may very well be true, at least as of this year. However, my points are:
  1. It's not up to Boeing to make decisions on how many competing engines are currently available for each of their 737 series. Of course, each airframe has limitations on what engines can and cannot be used, but by law, it is up to other companies to design, to manufacture, and to quality-control the engines that fit those parameters.
  2. And the key point that is relevant to this thread: since the emergency landing in Orlando appears to be an engine-related event,
    • it likely has nothing to do with MCAS — the primary suspect in this accident and in the recent Boeing troubles.
    • it likely has nothing to do with Boeing company, as the engines are not Boeing's responsibility; hence, I argued that bringing the Orlando emergency landing into this article doesn't make much sense. 凰兰时罗 (talk) 14:48, 29 March 2019 (UTC)
The point I was trying to make is that Boeing is limited in the engie options it can offer simply because there are few other suitable engines that will physically fit under the 737 wing. — Preceding unsigned comment added by 95.149.247.75 (talk) 08:26, 5 April 2019 (UTC)

"Per anti-trust laws, Boeing is not allowed to manufacture engines for their planes." I have severe doubts about the accuracy of that statement. There would be no specific prohibition in any of the Statutory Anti-Trust laws of the USA. If there has been such a prohibition, it could be found only in some case law decision, which would have to be a result of Boeing being sued by the US Fed Govt to prevent them from manufacturing their own engines.

I am not aware of Boeing being sued by the Govt to force it to cease and desist manufacturing aircraft engines. However, I am open to anyone referencing that kind of history, if it exists. If so, please give us the case name, date and number. Thanks, EditorASC (talk) 20:15, 7 April 2019 (UTC)

  • Not sure why we need to split hairs for such a side issue, but I did a brief research to add to the Quora reference that I mentioned earlier.
  • The case in question was settled before trial "in view of the Government's expressed attitude" (I quote Chicago Tribune below). At the time (1934, FDR administration), US Government was fighting "verticals," whereas Boeing practice since 1925 was to manufacture airframes, to manufacture their engines, and to operate its own airline with these planes. This whole operation was performed under the umbrella of United Aircraft and Transport Corp. As the result of the government investigation, this umbrella company was split up into Boeing proper, United Airlines, and Pratt & Whitney. Hence Boeing lost ownership of its engine manufacturer for large body planes (Pratt & Whitney) and couldn't restart such production, as this would re-create a "vertical." William Boeing, CEO of United Aircraft at the time, subsequently sold all his shares of United Aircraft/Boeing.
  • References:
    • Split is Planned by Aircraft Firm: United May Form 3 New Concerns // Detroit Free Press, May 25, 1934, Page 24
    • Split-up Plans of United Aero Unit Announced // The Los Angeles Times, May 24, 1934, Page 18 of Part II
    • Great Profits in Aircraft Sales: Senate Committee hears of increase... // Boston Globe, September 17, 1934, Page 6
    • Thomas Furlong, Four Air Lines Carry Bulk of Nation's Traffic // Chicago Sunday Tribune, September 1, 1935, page 9.
  • It is not immediately clear what exactly was agreed upon in 1934-1935, whether it was written down and if these records are available or sealed, but Boeing gradually stopped all its engine manufacturing (including for smaller planes) by 1968. Wikipedia article on Boeing provides more details of engine manufacturing within Boeing proper prior to 1968.
  • A salacious detail of this whole affair that I just found out, looking at the old newspapers: this "investigation" into Boeing of 1934 was conducted by the same Alger Hiss who turned out to be a Soviet spy. (The trial at his life time was inconclusive, but the later evidence from Vasili Mitrokhin's archive and Venona papers establish this beyond my reasonable doubt.)
凰兰时罗 (talk) 02:20, 8 April 2019 (UTC)
"Not sure why we need to split hairs for such a side issue, but I did a brief research to add to the Quora reference that I mentioned earlier."
It is not a splitting hairs side issue when an editor posts inaccurate historical information. If such is left there without challenge, some other editor might take that to mean it was factual and then end up posting such in a future or amended article.
You still have not posted any valid historical information that supports your original statement. The Boeing Company has never been prohibited to manufacture aircraft engines. The fact that Mr. Boeing purchased stock in a company that manufactured Pratt-Whitney engines did not convert the Boeing company into an engine manufacturing company at that time.
The 1934 Air Mail Act was not an anti-trust Statute of the USA. What it prohibited, following the Air Mail Scandal, was that US Mail contracts could not be awarded to Conglomerate Companies, or engine manufacturing companies, or aircraft manufacturing companies. Only individual airline companies were permitted to bid for those contracts. That prohibition of airlines being part of a vertical trust was the end result of the FDR Administration's conclusion that the alleged "Spoils System" of awarding mail contracts by Post Master Brown, under the 1930 Air Mail Act, had denied competitive bidding to smaller air carriers that were not part of such trusts.
There are only two Federal Anti Trust Statutes in the USA: The 1890 Sherman Act and the 1914 Clayton Act, which was partially amended by the 1934 Robinson–Patman Act. There is no language in those Acts, nor the 1934 Air Mail Act which prohibits any aircraft manufacturing company from making its own engines. I also am not aware of any Federal lawsuit under those Anti-Trust Statutes, that sought to compel Boeing to cease and desist from manufacturing aircraft engines. Since you have produced new information about Boeing manufacturing turbine engines during the 50s/60s, I have accordingly adjusted part of my previous statement to acknowledge your additional research. That new information, however, does amount to a contradiction of the original allegation -- namely that American Anti-Trust laws prohibited Boeing from manufacturing aircraft engines. Thank you, EditorASC (talk) 17:41, 11 April 2019 (UTC)

Reuters' Bird Strike and High Speed theory[edit]

I have just removed a section that was almost entirely quoting a Reuters article[1] as the one and only source. I am just wondering out loud why Reuters would even state the bird strike theory when the Ethiopian authorities have denied it.[2][3] Is it because Reuters is geared toward financial readers who might own Boeing stock? I sense an agenda because the Reuters article is written to focus the blame on pilot error and unforseen incidents like a bird strike, deviating blame from Boeing, which no other news article has done. So, one has to question Reuters' reporting/agenda. I shall never forget this reporting by Reuters.

Ethiopian authorities denied media reports that claimed a bird strike damaged one of the airplane’s angle of attack sensors. “Everything including the AOA sensors was functioning properly during take off. But a few minutes after takeoff the sensor began feeding erroneous data. We do not know what caused that,” Amdeye Ayalew Fenta, chief investigator of the Ethiopia Accident Investigation Bureau, told AIN[4]

There was high speed because they were trying to climb to gain altitude at full throttle, but with MCAS suddenly dipping the nose to gain more speed(!), the high throttle added to the speed gained when losing altitude. To make the plane gain more speed is entirely the function of MCAS because it believes (erroneously in this case) the plane is under stall from low speed, and uses gravity to gain speed.

Wikipedia is not the place for hypotheticals. Let us stick to facts, not agendas. Wait for the full report. WatchFan 07 22:12, 6 April 2019 (UTC)

Not agenda, the article is just poorly written mishmash in order to put "everything" in it and make it look interesting and new, also very short. WikiHannibal (talk) 09:30, 7 April 2019 (UTC)
My reading of that preliminary report indicates those news articles are not accurate. The pilots did NOT properly carry out the required emergency procedures for the "runaway stabilizer," which states that the manual cutout stab trim switches are to be moved to the "cutout" position and left there for the remainder of the flight. That the system began trimming AND again, after they initially turned off the stab trim switches, indicates they turned them back on again. And, they failed to reduce the engine thrust back to in-flight idle, once the fatal dive began. [1]EditorASC (talk) 20:42, 7 April 2019 (UTC)
@EditorASC:So this part is confusing. I have read what checklist I could get my hands on, the runaway trim checklist says cut-off and then trim manually and seems to end there (supporting your statement). But look at the November bulletin from Boeing I think it said if unable to trim manually you could go back to electric trim... for how long unclear. The thrust setting 75% N1 flaps up is in the unreliable airspeed checklist. Keep in mind that everything started with left-only stick shaker on rotate means it is complicated to figure out which checklists they were going through in what order. CVR will be key. But until then Max remains grounded, which is why this story is unusual and will continue to evolve.Greenbe (talk) 20:41, 8 April 2019 (UTC)
According to the ET302 Prelim Report (pg. 33), that Boeing bulletin stated: "Electric stabilizer trim can be used to neutralize control column pitch forces before moving the STAB TRIM CUTTOUT switches to CUTTOUT. Manual stabilizer trim [means the MANUAL moving of the stab trim wheels in the cockpit, by the pilots cranking those two wheels with their hands] can be used after the STAB TRIM CUTTOUT switches are moved to CUTTOUT." I find nothing in that bulletin that says the STAB TRIM CUTTOUT switches should be turned back on again, once they have been moved to the CUTTOUT position.EditorASC (talk) 18:21, 13 April 2019 (UTC)
@EditorASC: It depends on interpretation. They followed the checklist, but it has no resolution for the situation when the aerodynamic force on the elevator is stronger than hand-cranking (illustrated explanation [5]): "At 05:41:46, the Captain asked the First-Officer if the trim is functional. The First-Officer has replied that the trim was not working and asked if he could try it manually. The Captain told him to try. At 05:41:54, the First-Officer replied that it is not working." The original trim runaway checklist expects this would not happen. The emergency AD adds "Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before moving the STAB TRIM CUTOUT switches to CUTOUT. Manual stabilizer trim can be used before and after the STAB TRIM CUTOUT switches are moved to CUTOUT." Their only option to fix the mistrim was to re-enable and try the electric trim.
The deleted text needs to be re-instated. It is not just Reuters talking about the bird strike it is being widely reported. [6][7] Reuters say they have sources, not just quoting other stories. Bloomberg has high credibility right now because they broke the story on the 3rd pilot on the Lion Air flight after it was hidden for 5 months, and a week later it was confirmed and rest of that story has not been denied. Better wording would be"reports say bird-strike or debris are being investigated" and then include the Ethiopian denial. If you believe Reuters is biased for or against Boeing you need to cite a credible source. In any event the more important part is the thrust setting, which is noted in the prelim report.Greenbe (talk) 20:33, 8 April 2019 (UTC)
"Bird" is old news; it has been mentioned a month ago, for example https://chicago.suntimes.com/news/boeing-737-max-8-planes-grounded-for-inspections-after-ethiopian-airlines-crash/ . This is an encyclopedic article, not investigation, not news, not rumors. Please stick to that. The most recent and reliable source is the preliminary report, and perhaps expert analyses which directly put the facts from the report into context. Not reports that "a bird strike could have caused the calamity" (standardmedia) or "Investigators are also examining whether an angle-of-attack vane located near the nose of the Ethiopian plane malfunctioned or was damaged, perhaps by debris or a bird strike" (bloomberg - published before the preliminary report). Please leave speculation to the journalists recycling the story over and over again, and do not make a mess out of the talk page. WikiHannibal (talk) 21:11, 8 April 2019 (UTC)
The Chicago Sun Times reference you quoted only says "bird" exactly once "Other possible causes include engine problems, pilot error, weight load, sabotage or bird strikes, he said.". Any others to show this is old news? This could apply to any accident and is therefore meaningless in the context of B73 Max. The reason all the stories I link coincide with the prelim report release is that for the first time the FDR data has been released and shows a data spike, as noted in those stories. If your test of what gets in Wikipedia is restricted to the prelim reports, well the word "MCAS" appears in neither Lion or Ethiopian prelim reports so by that standard we should strike half of most of the articles? I think a balanced article can be written, and all of these speculations are part of the story, the response, the groundings and the political back and forth.Greenbe (talk) 23:51, 8 April 2019 (UTC)

References

  1. ^ "How excess speed, hasty commands and flawed software doomed an..." Reuters. 2019-04-05. Retrieved 2019-04-06.
  2. ^ "Ethiopian Airlines Flight 302 crash: Preliminary report says pilots followed Boeing's guidance". www.cbsnews.com. Retrieved 2019-04-06.
  3. ^ "Preliminary crash report confirms Ethiopian 737 MAX pilots lost control despite following Boeing's instructions". The Seattle Times. 2019-04-04. Retrieved 2019-04-06.
  4. ^ Bekele, Kaleyesus. "Ethiopian Max Pilots Followed Boeing Emergency Procedures". Aviation International News. Retrieved 2019-04-06.
  5. ^ "Vestigial design issue clouds 737 Max crash investigations". The Air Current.
  6. ^ https://www.bloomberg.com/news/articles/2019-04-03/ethiopian-air-pilots-said-to-follow-protocol-on-737-max-flight
  7. ^ https://www.standardmedia.co.ke/article/2001319486/british-newspaper-reports-ethiopian-jet-crash-caused-by-bird-strike

Interpretation of the Preliminary Report[edit]

The preliminary report contains, in the appendices page 26 and 27, part of the flight data as extracted from the FDR presented as graphs. From these graphs can be seen that the AOA sensor signal became erroneous immidiately after lift-off. Approximately one minute into the flight, after flap retraction, the automatic trim system is enabled. Data shows the system to act upon the erroneous AOA signal, but also clearly indicates that manual trim (trim as commanded by the pilots through the trim switches on both control wheels) has priority. The manuaul trim commands interrupt and are countering the automatic nose down inputs from the automatic system. From about two minutes after take off the stabilizer position stops to follow opposing manual and automatic command inputs. This concurs with the CVR recording indicating that the stab trim cut-out switches are used to stop stabilizer movement. About the same time the aircraft exceeds Vmo, the maximum allowable airspeed for the airframe. During the next two-and -a-half minute the flight is continued with a lot of manual elevator up input to counter for the now 'frozen' but seriously mistrimmed down stabilizer setting. With the stabilizer trim in cut-out the only way to remedy this situation is manual trim. The CVR transcript suggests that the first officer tried to do so but failed. This failure may have to do with an additional technical issue, but operating the stabilizer in this way quite strenuous, the more so if the other pilot is not available to handle the second crank of the manual trim wheels. In the same time interval, some 2.5 minutes, no attempt seems to be made to keep the flights speed in the normal range. Speed is allowed to increase to well above Vmo, increasing the airloads on the stabilizer and thus possibly further impairing manual control. Approximately 5 minutes after lift-off, two very short manual nose up trim commands are issued, after 5 seconds followed by an automatic nose down command. The stabilizer position follows through on these commands, thus strongly suggesting that the cutout switches, by this time, are reset to normal. At the end of the last automatic (nose down) movement of the stabilizer a short lapse in applied back-pressure to the yoke can be observed, resulting in an immidiate pich down. By this time the airspeed is close to 400kts, meaning that compressibility effects are shifting the effectivenes of pitch control over the aircraft away from the elevators towards the stabilizer as a whole. With the stabilizer mistrimmed nose down, the nose continues to drop and speed increases even further.

@92.110.148.249: "a short lapse in applied back-pressure to the yoke can be observed, resulting in an immidiate pich down" — the pitch down is result of the 5 second, 1.3 degrees automatic nose down trim by Mcas. The decreased pull on the yoke (8° to 5°) happened a few seconds later, while the pilots experienced negative G. Detailed reply below. — Aron Manning (talk) 03:35, 17 April 2019 (UTC)

The data suggests that the crew handled the initial runaway stabilizer situation correctly. Also returning the stab trim cut-out switches to their normal positions can be explained from Boeings suggestion, following the earlier 8max crash, as an attempt to use electrical trim to reset the stabilizer to an appropriate setting for the actual flight conditions. However, in order for this scheme to work a simultanouos manual nose up input of sufficient duration should have been issued. With this vital action not accomplished the automatic system, still acting upon erroneous AOA data, was allowed to worsen the situation further. The significant overspeed that had accumulated over the previous 2.5min robbed the crew of any elevator effectiveness that might have saved the flight. Why the crew allowed the overspeed to accumulate is yet unknown. Reducing power seems obvious, although fear for an additional pitch down moment may have been an argument.Cite error: There are <ref> tags on this page without content in them (see the help page). — Preceding unsigned comment added by 92.110.148.249 (talk) 15:32, 9 April 2019 (UTC)

[IP User amended the above and re-signed] 92.110.148.249 (talk) 19:02, 9 April 2019 (UTC)
Do you have anything that is not original research that can improve the article ? MilborneOne (talk) 15:48, 9 April 2019 (UTC)
@MilborneOne: There are lots of sources but apparently we are not allowed to quote them. Where is there a written rule on this? [1][2][3][4] and many more can be found. If you want a section on this you should reinstate the the section I already wrote that was deleted and we can clean it up and summarize. The key points are the thrust remained 94% and was unchanged the whole flight, this is called out in the prelim report for the first time. Why that happened is unknown, but since that is what the investigation is focusing on it can be written. I think it is becoming clear that until the full sequence is better understood the B737 Max will remain grounded.Greenbe (talk) 01:04, 10 April 2019 (UTC)
I tried to do that. WikiHannibal (talk) 08:53, 10 April 2019 (UTC)
@WikiHannibal: @92.110.148.249: Your point about Bloomberg saying the captain called for 238 kts yet that is not in the prelim report seems correct, report just says that 238 kts was selected not by who. The captain had called for the autopilot to be engaged earlier by calling "Command" which is in the report. Since Bloomberg state they are quoting a group of 737 captains analyzing the prelim report you can correct it is a mistake (as you did), but if they are quoting a confidential source with access to more data then need to be more careful (if it is a super important point, which I do not think this is .... yet). Crew interactions have yet to be dissected.
I re-read sections of the prelim report and have realized they do not mention autothrottle. Random online info says TO/GA switch is usually set for takeoff which engages autothrottle - that setting is also not mentioned in prelim report for reason unknown. You can start to read the sequence as they either expected the automation to reduce %N1 at some point, or they "forgot" that when autopilot disengaged on its own (or some other caution) that autothrottle would disengage and the speed setting would be ignored ... or something like that. Most of 92.110.148.249's summary is reasonable I think but the statement "The data suggests that the crew handled the initial runaway stabilizer situation correctly" is of course a very controversial topic. I reviewed the Boeing/FAA AD from November and it also says stab trim should stay in cutoff "for remainder of flight", as does QRH checklist. I don't think you can escape with the word "initial". But .... it's not so simple. We don't have the full CVR transcript, only a few select items that the prelim report mentioned. Greenbe (talk) 21:08, 10 April 2019 (UTC)
@DonFB: I took your suggestion and added speed select on autopilot and tried to restructure it to make if flow better. If you can see further improvements please edit.

References

The above interpretation is based solely on the priliminary report as published by the Etheopian Accident Investigation Bureau in the light of general principles of flight handling and some specific B737 characteristics. As usual, the preliminary report describes the facts known at this. With the available data a seemingly fairly complete picture of what happened can be drawn. It does not answer the question of why it happenend.92.110.148.249 (talk) 15:20, 10 April 2019 (UTC)
"...but also clearly indicates that manual trim (trim as commanded by the pilots through the trim switches on both control wheels) has priority."
That is not what is meant by the phrase "manual trim." MANUAL TRIM is when the pilots try to move the HS by manually cranking the two trim wheels in the cockpit, that are located on both sides of the center pedestal.EditorASC (talk) 18:07, 11 April 2019 (UTC)
@EditorASC:@92.110.148.249: The prelim report uses the term "manual electric trim" in a number of places, that is clearly what 92.110.148.249 means as per the brackets. The question remains: Can we have a paragraph trying to tie together some of the key items from the report?
"Also returning the stab trim cut-out switches to their normal positions can be explained from Boeings suggestion, following the earlier 8max crash, as an attempt to use electrical trim to reset the stabilizer to an appropriate setting for the actual flight conditions." Is there any reference link to support this statement? Greenbe (talk) 19:11, 11 April 2019 (UTC)

I think your guess is probably correct (that was how 92.110.148.249 interpreted the Prelim comments). This kind of problem is created when the writers of that Prelim Rpt invented some different nomenclature that is inconsistent with that which Boeing uses in its FOM NNC checklist procedures, or in the subsequent Boeing November bulletin.

Boeing does not combine the word "manual" with "electric trim." When Boeing uses the term "manual trim," it is talking about the pilots manually cranking the two cockpit wheels that are connected via cables to the HS.

As to a Boeing "suggestion," I haven't run across anything like that. From page 33 (last page of the ET302 Prelim Report):

"Electric stabilizer trim can be used to neutralize control column pitch forces before moving the STAB TRIM CUTTOUT switches to CUTTOUT. Manual stabilizer trim [means the MANUAL moving of the stab trim wheels in the cockpit, by the pilots cranking those two wheels with their hands] can be used after the STAB TRIM CUTTOUT switches are moved to CUTTOUT."

I find nothing in that bulletin that suggests the STAB TRIM CUTTOUT switches should be turned back on again, once they have been moved to the CUTTOUT position. However, I do think Boeing should add some statements which strongly emphasizes that pilots should countermand unwanted HS trim with their yoke electric trim switches, until they get the HS back to the position they want, and then IMMEDIATELY move the CUTTOUT switches to the CUTTOUT position.EditorASC (talk) 22:08, 13 April 2019 (UTC)

a short lapse in applied back-pressure to the yoke can be observed, resulting in an immidiate pich down
— User:92.110.148.249

I suggest revising this. According to the preliminary report, page 10:
"At 05:43:20, approximately five seconds after the last manual electric trim input, an AND (Aircraft Nose Down) automatic trim command occurred and the stabilizer moved in the AND direction from 2.3 to 1.0 unit in approximately 5 seconds. The aircraft began pitching nose down. Additional simultaneous aft column force was applied, ..."
The FDR data diagram on page 26 shows "Pitch Attitude Disp" starts decreasing from ca. 3 degrees at 05:43:22, while the mcas Nose Down trim is active between :20 and :25 seconds. 3 seconds later at 05:43:25 the "Ctrl Column Pos" starts to move from ca. 8 degrees to 5°, the same time as the "Accel Vert (g)" fell from 1.0g (level flight) to -0.4g (nosedive). The sudden negative G environment and stronger forces on the elevator control surface might be the cause for the column position moving forward. — Aron Manning (talk) 03:35, 17 April 2019 (UTC)