China 737-800 Plane Crash

Was it a 737 Max?

No...

Thanks, a bit like a spot-the-difference puzzle!

Was it a 737 Max?

No, it was a 737-800, an earlier version than the max.

https://www.cnn.com/2022/03/21/business/boeing-jet-crash/index.html

It was in a very steep dive at the end...

https://mentourpilot.com/crash-china-eastern-737-lost-with-132-on-board/

Thanks

I heard that it wasn’t…

Pilots are trained to effectively deal with decompression. The flight data recorder should supply the reason for the disaster.

Right now, it’s all speculation…

but like flight 1549 where Captain Sully landed on the Hudson… the training never covered that type of situation, and it was experience that saved the passengers.

No reason to dive to a lower altitude, the plane is equipped with supplemental oxygen masks.

Passenger oxygen only last for a few minutes (10 to 15 minutes is what I read), so yes, the plane does need to dive to lower altitudes before the oxygen runs out.

However, you don't need to do a steep dive (as long as you get to 10,000 feet within a few minutes) because a steep dive puts the airframe under stresses that could damage it. You may get to 10,000 feet fast but the plane might be too damaged to continue flying.

regards,

Vulcan

A descent rate of 31000 ft/min reported (~350 mph) does not seem to be consistent with an airplane that is still flyable.

A skydiver's terminal velocity is around 10k ft per min...

Are you suggesting a possible 9/11 type of high-jacking?

There's not enough information to eliminate anything at this point. It's amazing that investigators can determine a cause just from collected debris. Hopefully the black boxes survived and can be read.

That's a huge part of the investigation where it takes time, clearing out a hanger and somewhat laying out the recovered pieces on the floor as to the position where they were on the plane.

Quite a forensic operation and investigation.

SOP for commercial jets. Masks are emergency only and the descent profile fits the traing manuals ... after that...?

Lets wait for proper evaluation not guesstimations from guesstimators shall we?

https://www.geo-fs.com/geofs.php

They hit the ground at near Mach 1...

Who knows at this stage.
I doubt the mach 1 bit though.
SOP for decomp is (it varies somewhat with weight and temp - but near enough for this purpose) go flight idle, speed brakes deployed, initiate nose down -1g max (not trim down), IAS below 350kts deploy 15º flaps, commence 1g pull up at 15,000' - there are a truck load of other checks and stuff you and your right seat will be doing at this time as well.
That link ironically bought up the plane I learnt to fly in back when Methuselah was a young bloke.

Max speed is about 288 mph below 10k ft...flaps cannot be deployed at speed without damage to the horizontal stabilizer...max speed at altitude is 583 mph....mach 1 is 767 mph...speed was est from film footage of dive to ground...

http://www.b737.org.uk/limitations.htm

It could have been a downdraft or microburst or wind shear that caused the initial loss of control and altitude...

https://safetyfirst.airbus.com/wind-shear-an-invisible-enemy-to-pilots/

Mach = 767 mph at sea level at≈20ºC
V_max at 39.000' ≈ M 0.88 and they do not cruise at V_max
Cruise is normal at a little < M0.8
Incremental lowering of the flaps is SOP in decomp and the buffeting the horizontal stabilisers suffer is akin to the edge of a cyclone - not recommended but trained for ... damage? Doubt it. Tear the tail feathers off it would have impacted via ballistics.

If they were just cruising along getting ready for descent for landing and they experienced a micro-burst that forced them down, I believe the proper procedure is to throttle up and try to regain control, now after dropping so far the speed may have increased and finally clearing the down force the g-force, upon hitting an air mass in the opposite direction, could have exceeded 4 G's enough to cause a temporary blackout for everybody on the plane, then somehow the angle of attack went negative and the final plunge began, at this point the speed could have been too great to restore control...the typical glide path for landing approach is something like 2.5° below horizon with throttle back....

(Attempt 2)
Who knows at this stage.
I doubt the mach 1 bit though.
SOP for decomp is (it varies somewhat with weight and temp - but near enough for this purpose) go flight idle, speed brakes deployed, initiate nose down -1g max (not trim down), IAS below 350kts deploy 15º flaps, commence 1g pull up at 15,000' - there are a truck load of other checks and stuff you and your right seat will be doing at this time as well.
The main image shows about 1 minute to descend 19,000' so vertical speed was only about 3.6 miles per minute which when you work with a basic cruise of the 737-800 it could have possibly got way up there but 639kts at 10,000' I doubt - the impact would have been markedly different.
Following your first post I would though give credence to a deep stall scenario meaning velocity of airflow over wing is massively disrupted.
Dunno maybe some fighter jock some where has got into a stall post mach at low altitude - high I know it is a very distinct possibility ... low, yes pull to may g and you may get a weird response like the plane flicking out of a turn or some such (Mirage III was good at it)
Your link ironically bought up the plane I learnt to fly in back when Methuselah was a young bloke. Ah the bush chasing cattle......

Until they recover the flight data recorder, and the flight-deck voice recorder, we can only speculate...

So they've finally analysed the contents of the FDR... and, https://www.youtube.com/watch?v=n0EDSRrexug

It is possible that the masks were already down for some time. Mentour pilot say that the pilot requested to drop lower which was denied because of traffic below them. They did not reply on the question if it was an emergency.

Someone or something initiated a dive . There were attempts to pull back at 25000 , 19000 but the down instruction was stronger . The pull back below 10000 was to late and could have produced too much G's . Then the down instruction won again.

At least the black (red) box has been recovered today. Unfortunate loss for many.

That’s…

Bit there are actually (2) black boxes… hopefully they are able to recover both and both are intact.

The first box is the flight data recorder (FDR), which records flight data. The second box is the cockpit voice recorder (CVR), which records audio in the cockpit.

Looks like a wing tip...

https://www.bloomberg.com/news/articles/2022-03-24/china-crash-mystery-deepens-as-evidence-suggests-midair-breakup?srnd=premium

https://www.quora.com/Can-a-planes-wing-break-due-to-heavy-turbulence

That does look like a composite structure...

..."Airplanes don't constantly break because the limit or “design” load — 3.8G positive for normal category and half that negative—is not the load beyond which the airframe is expected to fail completely.

...Composite structures behave quite differently from metal ones.

Fiber-reinforced composite materials do not exhibit plastic deformation; they deform elastically to a certain point and then fail with explosive suddenness."...

..."Glass or carbon fibre-reinforced plastic nosecone, fairings and fin tip. "...

..."The nosecone, wing and fuselage fairings, fin tips, the fairings of the flap actuators and other non-stressed components are constructed from glass and carbon fibre reinforced plastics (GFRP and CFRP). The rear of the engine nacelles are constructed of graphite, Kevlar and glass fibre composites.

In February 2000 an advanced carbon graphite winglet developed by Boeing became available as an option on the 737-800."....

https://aviation.stackexchange.com/questions/79539/what-materials-form-the-structural-elements-of-the-boeing-737

This shows how things can quickly get out of control...and why the rules must be followed so closely, not to mention training on that specific aircraft for the pilots...

This is about a 747 back in 1985 chronicling the loss of situational awareness from a simple problem with one of the 4 engines...

this may be an armchair pilot opinion.

Its unbelievable how tough that plane was/is. It appears, that one item if done would have avoided it all of this and that was shutting down that bleed valve.

I can understand the situational awareness issue flying through a clouds like that…

Fighter pilots go through training when doing a water landing, of exiting a flooded cabin/cockpit… they may lose which way is up.

I would also think, that experience is good, to a certain extend. Highly experience like this pilots had it went the other way.

Also I believe now-a-days, airline pilots are tested in simulators given certain random situations to access the pilots abilities.

It's easy to become disoriented when flying different maneuvers, if you can't see anything but clouds or darkness, then it's almost guaranteed, that's why you must have complete faith in your instrumentation....lose that, and anything can happen...why this sensor wasn't changed to begin with is a mystery to me...and why pilots don't get a full maintenance history as part of pre-flight, is also a mystery...

Friend of mine was a chopper pilot in the Army… as part of his training, they blacked out the windows on him and he had to fly the chopper by instrumentation alone.

"...and why pilots don't get a full maintenance history as part of pre-flight, is also a mystery..." um, no it isn't.
The "...full maintenance history ..." for, even a reasonably new'ish, 3-5,000hr 737 is multiple huge volumes. You do get the latest maintenance sheet and any outstanding beef's.

Wouldn't you think that would be informational overload for the pilots.

Yep. Big time.
AND it would take you a month+ to read them and half of it you wouldn't understand anyway, unless you were certified on the engine/s, airframe, avionics, life systems, etc ...
ANNND yes they are available if you ask. (You normally get and/or should ask for the last pilots beef sheets and responses)
In, a hypothetical, and you work for a big airline that has 200 of the said BoingBus 373Minimums, you could in theory get to drive every single one in a calendar year, so you would have to read, in the said year, 200 x 8 150mm thk binders (ave per ship. A 10,000hr one could be 20+ if you want to see the lot) = 1,600 binders per year plus do all your normal flight planning ... for the said minimum 200 flights ...
I use the term "binders" for a specific reason. I've seen unsigned sheets. I like to see the originals WITH a signature, and yes they can be scanned into a computer, and are, BUT a big beef I'd want to sight the original so that when I come back from hell I know which idiot to take back with me.

Never happen, with the shortage of pilots we have now, even before the idiotic presidential mandates, making it even worse with pilots now leaving or taking early retirements.

or wait, maybe have even one more presidential mandate requiring it, where now you make an announcement…

Hey, you on the bike… do you know how to fly a plane? We need a pilot.

theoretically…

I'm talking about access to the full maintenance history, the pilot could go back as far as he wanted.....I would like to see at least the last half dozen of those sheets...If something was failing intermittently, I would want that changed...just because something is working on the ground doesn't mean it will be working while in flight...those records should be digitally available anyway...

This guy's videos about aviation matters are pretty good.

https://www.youtube.com/user/blancolirio/videos

This had happened back in 2018 where an engine exploded/tore apart, and the pilot landed it.

So what did the "black boxes" tell us...? The co-pilot was having a bad day, and decided to murder all the people entrusted to his care...you can't fix crazy, but you can eliminate it when you see it, and you stand a better chance of seeing it if you are looking for it....every passengers' worst nightmare, a suicidal pilot....He shouldn't have been demoted, he should have been banned from flying and institutionalized...