Boeing China Eastern 737 Crash: What Caused the Unusual Cruise Phase Tragedy?

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On March 21, a China Eastern Airlines 737-800 crashed during the cruise phase, a typically safe flight segment, killing all 132 on board. The aircraft reportedly entered a rapid descent, reaching speeds of 30,000 feet per minute, which raises questions about potential causes such as runaway trim or intentional actions. Speculation about pilot suicide or mechanical failure is prevalent, though many argue that a power loss at cruising altitude should not lead to such a drastic outcome. The intact fuselage seen in videos suggests that in-flight breakup is unlikely, but the investigation is ongoing to determine the exact cause. The recovery of flight recorders is crucial for uncovering the circumstances surrounding this tragic incident.
  • #31
This is certainly a peculiar event. If the vertical stabiliser was lost it would have tended to flat spin, which it did not. I could not see the wings in the surveillance video, so either the wings were missing beyond the engines, or roll attitude was under control. Without voice communication notifying an emergency, the obvious explanation of murder-suicide by pilot is possible. In this situation, any evidence of a midair breakup will be on the ground, not lost at sea. We must wait for the results of the investigation before reading the certain explanation.
 
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  • #32
Oldman too said:
I've never seen or heard of an example where an aircraft flies straight down like the one in that image, what would it take to hold the aircraft in that attitude for an extended nose dive?
The video that @anorlunda posted addresses that. It seems to take a non-passive forced nose down attitude from a mechanical failure or a persistent cockpit input.

anorlunda said:
Here's the data I saw at
View attachment 298775
The commentary notes that the dive started very close to the point where the flight
plan would call for beginning descent to the airport.
 
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  • #33
fresh_42 said:
That's a good question. A B-737 is not an aerobatic machine that can perform all kinds of maneuvers. E.g. the extended suicide mentioned above was done by programming the autopilot to a height below the height of surrounding mountains. The determined crash actually took a while, and stuff, as well as passengers, knew it. I assume that such a nosedive is extremely difficult to get in, especially as you can no longer sit and fly.
I'm not a pilot, however I've spent years on MS Flight Simulator, a very good physics model with a good variety of aircraft. Not that I'm suicidal or anything but I've tried to perform that exact same maneuver as described in the article (and image) It's way beyond my ability no matter what plane, weather conditions etc. I have to admit I'm baffled.
 
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  • #34
The glide ratio of a 737 with no power is on the order of 17:1. Starting from 29000 feet, down to 3000 foot mountains, it could glide about 130 km. Air Transat 236 (Airbus 330) ran out of fuel mid-Atlantic. It glided 121 km to the Azores and landed safely. https://en.wikipedia.org/wiki/Air_Transat_Flight_236

For the sake of the pilot's families, please don't speculate publicly about suicide. You can believe it privately, but don't be so cruel as to post it on a forum that is indexed by Google.

Hijacking is another explanation for a deliberate descent.
 
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  • #35
berkeman said:
Thanks for the link. I still call BS (on him, not on you). This senior editor is obviously not a pilot. (of course, neither am I, but I know how my paper airplanes behave when they "lose power"...) :wink:
@Oldman too

Sorry guys, that's my source. I picked it because it had the video link and didn't read the article. Yes, it's clearly BS. Perhaps an opening argument/pre-emptive strike against Boeing?
 
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  • #36
russ_watters said:
There was one I vaguely remember where part came off but it mostly remained intact while it nosed-over into the ground. I can't remember if it was the nose or tail though...
Googling tells me the front section of TWA 800 ripped off and it continued flying for a bit (even climbing) after its center tank explosion. I don't think that's the one I was thinking of though.
 
  • #37
russ_watters said:
Googling tells me the front section of TWA 800 ripped off and it continued flying for a bit (even climbing) after its center tank explosion. I don't think that's the one I was thinking of though.
And AF447 crashed because the pilots were actively working against the machine confused by their misinformation. Or think of AQ243 when parts of the roof went off and the pilots still landed safely. Or JL123 were the heck broke away and the pilots were still flying for quite some time.
 
  • #38
fresh_42 said:
And AF447 crashed because the pilots were actively working against the machine confused by their misinformation.
Yes, that's the one I was referencing when I said "riding a stall all the way down". The first officer held the stick all the way back throughout almost the entire sequence of events after the angle of attack sensor airspeed indicator failed. Inexplicable actions.
 
  • #39
russ_watters said:
Yes, that's the one I was referencing when I said "riding a stall all the way down". The first officer held the stick all the way back throughout almost the entire sequence of events after the angle of attack sensor airspeed indicator failed. Inexplicable actions.
I recall that, isn't that the one that the ground crew forgot to remove the airspeed indicator cap prior to take off ?
 
  • #41
Oldman too said:
I recall that, isn't that the one that the ground crew forgot to remove the airspeed indicator cap prior to take off ?
No, it just flew through the top of a thunderstorm and iced-up a little.
 
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  • #42
Oldman too said:
I recall that, isn't that the one that the ground crew forgot to remove the airspeed indicator cap prior to take off ?
AFAIK one of the two Pivot tubes was iced due to washing the machine before the start and water came in.
 
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  • #43
fresh_42 said:
AFAIK one of the two Pivot tubes was iced due to washing the machine before the start and water came in.
No, that one was an aoa sensor on a different plane:
https://en.wikipedia.org/wiki/XL_Airways_Germany_Flight_888T

[edit] This one had implications for the Boeing 737 Max/MCAS issue as two sensors froze in the same position, one didn't and the computer rejected the functioning sensor because it was the outlier.
 
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  • #44
Oldman too said:
I recall that, isn't that the one that the ground crew forgot to remove the airspeed indicator cap prior to take off ?
At the risk of one more irreverent sidebar...

I recently designed a spaceship for a sci-fi game whose ship name, emblazoned in red on its flank, was "Remove Before Flight".
 
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  • #45
Quite a few years back a commercial airliner augered into swampland in Florida IMS. The impact crater of this flight reminded me of that event. Data recording boxes eventually recovered. Seem to remember a cargo fire severed controls to the tail or the flight crew was attempting to fix an errant indicator lamp, as mentioned above.

Learned a new term today for cockpit monitors listening to video from @anorlunda 's post: 'glass'.
 
  • #46
fresh_42 said:
Honorable. However, the B737 is a workhorse for decades. Mid-flight almost rules out a maintenance problem, an intact plane rules out a bomb or other causes for physical breaks. The fire rules out a fuel problem. The stall almost rules out a steering or trim problem.

There is not much left for reasonable causes.
From what I saw, it looked like a good portion of the tail was missing. Is that enough for an aircraft to come down so extremely?
 
  • #47
valenumr said:
From what I saw, it looked like a good portion of the tail was missing. Is that enough for an aircraft to come down so extremely?
Where did you see that?

Airplanes are nose-heavy. A broken-off horizontal stabilizer will make a plane pitch down toward the ground.
 
  • #48
russ_watters said:
Where did you see that?

Airplanes are nose-heavy. A broken-off horizontal stabilizer will make a plane pitch down toward the ground.
I saw this, but I can't really testify to it's veracity:
fark_IxtwyaYTTL16CLrpTPK_pUk2QkA.jpg
 
  • #49
valenumr said:
I saw this, but I can't really testify to it's veracity:
Where? Please provide the source.

The vertical stabilizer is so-named because it is oriented vertically, so it obviously has nothing to do with vertical motion. American 587, which crashed in Queens just two months after 9/11 did so because its vertical stabilizer separated. It lost lateral stability as a result. A plane would act like a lawn dart if the horizontal stabilizer detached. The description in the image is basically technobabble.
 
  • #50
russ_watters said:
Where? Please provide the source.

The vertical stabilizer is so-named because it is oriented vertically, so it obviously has nothing to do with vertical motion. American 587, which crashed in Queens just two months after 9/11 did so because its vertical stabilizer separated. It lost lateral stability as a result. A plane would act like a lawn dart if the horizontal stabilizer detached.
It was a repost in a forum from a tweet from a blog or something. I don't have the original source, thus I have little faith in it's truth. It is claimed to be a zoom from the live video (which happened) of the plane crashing. But it could just be a photoshopped picture of a plane rotated 90 degrees.

My question was, that if the plane lost most of the tail section, would it lose so much lift that it would just go straight down?
 
  • #51
valenumr said:
It was a repost in a forum from a tweet from a blog or something. I don't have the original source, thus I have little faith in it's truth. It is claimed to be a zoom from the live video (which happened) of the plane crashing. But it could just be a photoshopped picture of a plane rotated 90 degrees.
Ok. I think it's likely to be fake.
valenumr said:
My question was, that if the plane lost most of the tail section, would it lose so much lift that it would just go straight down?
As I said above, the vertical section of tail (shown broken off in the likely fake pic) doesn't do anything for up/down motion. But if the horizontal section broke off, yes, it could go straight down. As I said, planes are nose-heavy. The tail (horizontal stabilizer) doesn't add lift directly, it pushes down to push the nose up.
 
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  • #52
valenumr said:
My question was, that if the plane lost most of the tail section, would it lose so much lift that it would just go straight down?
It would not lose lift, no. It would lose attitude control.
 
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  • #53
Update
1648072103561.png

1648072238379.png

Blue, airspeed
Grey, Vertical speed
Yellow, Ground speed

The source says that they appeared to pull up at some point. It is possible that they stalled the wings during the pull-up.

He also talks about the picture of a plane diving with no tail (the one discussed earlier in this thread.) He says, that picture is not the accident aircraft, it comes from a TV show about some other accident.

Misinformation abounds.

My source:
 
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  • #54
anorlunda said:
...
The source says that they appeared to pull up at some point. It is possible that they stalled the wings during the pull-up.

He also talks about the picture of a plane diving with no tail (the one discussed earlier in this thread.) He says, that picture is not the accident aircraft, it comes from a TV show about some other accident.

Misinformation abounds.
...
The video in this interesting post clears up misapprehensions concerning stalls, attitude and their relation to angle of attack. Descriptions of inflight data recording also excellent.

Learned that air traffic controllers speak Mandarin communicating with pilots on these internal flights, presuming the voice record is authentic. English standard on international ATC comms?

[edited meandering post. Thanks, Mike :wink:]
 
Last edited:
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  • #55
anorlunda said:
Misinformation abounds.

My source:
Great info, thanks anorlunda. I like your source -- he seems very straightforward and knowledgeable. It's great that they are finding the flight recorders, and seems very significant that there was an attempt near the end of the descent to recover the aircraft.
 
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  • #56
berkeman said:
the radio report of the crash, the commentator (CBS? NBC?) said
Oldman too said:
From the NYPost article.
MSM never gets this aviation stuff right initially. We'll just have to wait a bit and see. But if you want good reporting try this guy:

 
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  • #57
Referencing the video in post #53 (https://www.physicsforums.com/posts/6613522) by @anorlunda:

Around 7:46 of the video, the presenter asks for help removing the music from the recording.
The voice comes thru rather clear with the following equalizer settings:
Code: 
 Hz      db
100     -12
200      +2
600      +3
1k      -12
3k      -12
You may want to optimize the higher frequencies a few db.

I do not have a good way to extract and save the audio here. Hopefully someone reading this can use the above settings for extraction.
Also I could not find a way to directly commumicate to the author of the video. With over 700 comments it's probably useless to post there.

Hope it helps.

Cheers,
Tom
 
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  • #60
Yeah, that PPE is not just to keep them from contaminating the crash site...
 
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