China Eastern Airlines flight MU5735 737-800 Crash 17

[Eufalconimorph]

Avherald.

Reuters.

Dash cam footage showing crash angle.

Video of security camera video, straight on (angle of descent looks steeper than reality).

 

[Debirlfan]

Twitter "Aviation expert David Learmount explained to @CGTNEurope ..." argues for emergency decent.

But why would they be in that big of a hurry to descend? It's not like they were high enough that breathing would be an urgent issue.

 

[Sym P. le]

If they recover anything off the voice recorder, maybe we will soon find out. None of this makes much sense.

 

[dik]

Not a great news source... The flight crew did not respont to ATC, it would appear. A possible explanation is that, if you're up to your neck in gators, no time to answer the call...

https://www.dailymail.co.uk/news/ar...d-multiple-calls-air-traffic-controllers.html

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[verymadmac]

It is possible to shake the tail off a plane, even without manufacturing or maintenance defects.

While that load case is missing from FAR 25, it is noted that missing that load case was actually an Airbus problem, rather than a Boeing problem.

 

[verymadmac]

But why would they be in that big of a hurry to descend? It's not like they were high enough that breathing would be an urgent issue.

At 28000 ft the Time of useful consciousness is 1.25 to 1.5 minutes, noting those figures are for 20 somethings. 25,000 ft is I seem to recall about the limit of survival (you may be unconscious but probably unlikely to die).

 

[Alistair_Heaton]

29000 ft time of useful consciousness is 60 seconds if a explosive decompression occurs. But we have oxygen systems and quick donning masks.

It is a possibility but even an emergency descent you wouldn't get anywhere near the attitudes that this aircraft did. Its done with automatics anyway. Dial in 10000ft flight level change which brings the thrust back to idle, max spoilers speed 350 knts and the plane will go down at about 6000 to 8000 ft per min depending on weight.

Eastern China has 3 pilots in the front all of the time. And this flight was a command upgrade flight apparently. So LHS was the new Captain. RHS was a trainer who had over 20 000 hours and the jump seat had a normal first officer.

Suicide always comes up with these sort of things but in the grand scale of things its unlikely. But for some reason people seem to prefer it to component failure then messing up a drill.

Most of the time its a technical issue which is not handled correctly by the crew. But as we saw in the MAX threads the 737 NG and MAX are pretty much unique these days for commercial jets not having an EICAS and ECAM system and have a distributed caution warning system. And having a colossal paper QRH to find and then find the correct card and read through it.

https://www.737ng.co.uk/737-800 Quick Reference Handbook (QRH).pdf

Its actually very hard to get the aircraft into that attitude with manual control inputs but not impossible. And then we have the inability to manually trim the aircraft once its outside a speed window of the current setting. Which we discussed at great length in the MAX threads.

The tail empennage produces down force (in the aircraft xyz coordinate system) from my understanding of the system even if the jack screw goes to the stab the elevators should still work. Bit of a mind screw because to get the nose to go down you would apply back pressure which the elevator would then float the stab to give it. But it might work.

My gut feel is something has gone wrong with the trim system but what I have no clue. There was issues with the wiring runs of various things came to light in the MAX which were deemed to be outside compliance with the NG as well. Now they have the CVR and it looks like its in a good state hopefully the FDR will turn up soon. Quite what the investigators will release was behind my question above

What's your feeling for how they are going to investigate it?

 

[dik]

I posted that link, because I thought it was added info... not to point to possible suicide. I don't know yet, but I suspect the crash was the result of a catastropic electro/mechanical failure of some kind, of the system and that all the aircrew were desperately trying to remedy it. Communication with the rest of the world would be the last of my concerns at a time like that.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Alistair_Heaton]

While that load case is missing from FAR 25, it is noted that missing that load case was actually an Airbus problem, rather than a Boeing problem.

It was everyone's problem all OEM's changed the manuals after that one and put a warning in about cyclic input of all controls.

You can break every aircraft doing it.

And the FAA completely changed the US flight upset training. Prior to that all commercial FAA pilots were taught to lift the wing in flight upsets using the rudder. In EASAland we were/are taught to only use the rudder to control the yaw. And then correct any roll attitudes using roll control inputs.

The latest gen simulators have a structural load module now and when we do flight upset training we get plots of structural loading compliance. With FBW machines with it in normal mode the aircraft protects itself in xyz. In direct mode (failure mode without any protections) you can easily step outside the limits if you don't keep the yaw indicator centred.



In fact its not uncommon to get FDR exceedance emails when you hit turbulence on approach when your in a 30 deg bank. You can get round it by applying half bank to the autopilot but that really screws up ATC vectoring if you do that. But I think they are working on some software change to deal with it. As you more than likely know it generates a phase 1 inspection which is more of a paperwork PIA for the technicians than actually does any damage.

High Lateral Acceleration [Lateral G - max abs = 0.42 G]

That's one I got in the storms last month

All pilots are taught Aviate Navigate Communicate. And to be honest how is declaring a Mayday going to help this situation. Also the problem is as soon as you start talking then you will be asked questions like how many souls on board, do you have any dangerous goods what the problem is etc etc in most places in the world. There are a few exceptions. The Dutch controllers at Schiphol are poo hot dealing with sick aircraft no nonsense off them.

 

[dik]

Neat... the index items are hot links to the section referenced... that's really handy.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Alistair_Heaton]

that's not what they have on the aircraft. Its a 1" thick plastic ring binder.

EICAS systems links into the ECAM system and automatically bring up the correct electronic checklist for the system failure A220 also prioritises them as well. As sometimes by the time you have finished the first one its fixed all the others and they disappear.

 

[AusG]

Anyone covered accidental deployment of reverse thrust?

 

[Alistair_Heaton]

Here is a report of a 767 that had that.

http://www.rvs.uni-bielefeld.de/publications/Incidents/DOCS/ComAndRep/LaudaAir/LaudaRPT.html

 

[1503-44]

Hey, its a new spreadsheet.
Gs were indeed wrong.
New max is 3.7

Gx Gy G total
0.0 0.0 0.0
0.0 -0.3 0.3
0.0 -1.8 1.8
-0.2 -0.7 0.7
0.2 -2.8 2.8
[highlight #FCE94F]0.5 3.6 3.7[/highlight]
0.1 0.5 0.5
0.0 -0.7 0.7
0.0 -0.2 0.2
0.2 0.7 0.7
-0.1 0.7 0.7
-0.2 0.7 0.8
-0.2 0.3 0.4
-0.1 -0.3 0.3
0.0 -1.1 1.1
-0.5 0.7 0.9


A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[Sym P. le]

Whew! I thought I would pass out there for a bit. How does 3.7 compare to a roller coaster? I still imagine it was uncomfortable but at least at this rate it's more plausible that the aircraft stayed together.

 

[AusG]

reverse thrust accident report

Thanks. that was both horrifying and informative. It that a real possibility here? seems so to me but I am not knowledgeable in such things

 

[Alistair_Heaton]

Without G pants +3.7G will give some people eyesight issues. But it depends on the duration.

The normal max G is 2.5 G under FAR25 flaps up.

 

[1503-44]

60° bank pulls 2g. I did that exactly once. On a Braniff flight through a Houston-Dallas wintertime storm front in 1969 with 40k ft thunderstorms on each side, there was a stewardess and a drink service cart and a lot of glasses riding on the ceiling for 30 seconds. That was all I ever wanted to see. Not kool.

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[Alistair_Heaton]

Don't know if its a possibility or not. I have never been rated on the 737 so don't know.

I would have liked to think that there are multiple interlocks to stop it being deployed in cruise. I think also they are depowered from the hydraulic system via the gear three position handle.

Trim runaway nose down would be more likely in my opinion.

 

[Debirlfan]

They found a piece of the plane 10 km away.

https://www.reuters.com/world/china/chinese-search-second-black-box-crashed-jet-2022-03-24/

 

[thebard3]

Finding a piece 10 km away certainly changes the story.

Brad Waybright

The more you know, the more you know you don't know.