Ethiopian Airlines crash

SYB_DC

Winger
There was a plane then ended up being flown upside down sure that was to do with that?

Edit: This


Jammed stabalizer so controls were fooked.
Totally different type of plane. The 1990s rudder hardovers were earlier-generation 737s. The jackscrew failure followed by upside down flying and a splash into the Pacific was an MD-80. That one was a maintenance issue, whereas the 737s were a design flaw.
 

dangermows

Striker
Totally different type of plane. The 1990s rudder hardovers were earlier-generation 737s. The jackscrew failure followed by upside down flying and a splash into the Pacific was an MD-80. That one was a maintenance issue, whereas the 737s were a design flaw.
Was it the same issue though?

the transcript of what was being said on that Brazil to France crash is one of the worse things I have read
The knacker pulling up instead of pushing the nose down.
 

SYB_DC

Winger
Was it the same issue though?
Not really. The issue on the Alaska bird is that the jackscrew broke (well, the threads ripped off, but it makes the thing equally useless).

With the 737MAX the assembly itself appears to have been fully operational for both crashes, it's just what the onboard computers (in this case, the MCAS system, which is new for the MAX) were telling it to do. The real mystery here is why the pilots didn't just turn off the system that was causing the control inputs. After the Lion Air crash, this issue became well-known. What seems likely is that this one won't be solely MCAS-caused. Something else was wrong as soon as this flight took off. Apparently the stick shaker was on as soon as the plane left the runway, which means the plane thought it was stalling right above ground level, with the flaps still down - MCAS doesn't become active until the flaps are retracted.
 

gards2

Striker
Rudder hard-over? Oh, that would be awful if that's the case. The plane determined to pitch it's nose down.I also saw that AI episode. Pilot helplessly fighting the controls. That was the pin that came loose wasn't it. Threads gone because it wasn't lubricated enough.

These are new planes!
 

dangermows

Striker
Not really. The issue on the Alaska bird is that the jackscrew broke (well, the threads ripped off, but it makes the thing equally useless).

With the 737MAX the assembly itself appears to have been fully operational for both crashes, it's just what the onboard computers (in this case, the MCAS system, which is new for the MAX) were telling it to do. The real mystery here is why the pilots didn't just turn off the system that was causing the control inputs. After the Lion Air crash, this issue became well-known. What seems likely is that this one won't be solely MCAS-caused. Something else was wrong as soon as this flight took off. Apparently the stick shaker was on as soon as the plane left the runway, which means the plane thought it was stalling right above ground level, with the flaps still down - MCAS doesn't become active until the flaps are retracted.
Thank you, very interesting.
 


Just picked this up from the PPRuNe forums. Its parameters from the Lion Air crash. The person who posted it specifically mentions the automatic & manual trim detail and that it looks "chilling". To me it looks like whatever the pilots are doing, the software/autopilot is doing the opposite.

@HillView Aviator is this something you can shed more light on?
 

SYB_DC

Winger
Rudder hard-over? Oh, that would be awful if that's the case. The plane determined to pitch it's nose down.I also saw that AI episode. Pilot helplessly fighting the controls. That was the pin that came loose wasn't it. Threads gone because it wasn't lubricated enough.

These are new planes!
It's very unlikely. The hardover issues were caused by failures of a component in the tails of earlier 737s (up to the -500 series) that had no redundancy. That component has redundancy in the -600s and onwards, including the MAX.



Just picked this up from the PPRuNe forums. Its parameters from the Lion Air crash. The person who posted it specifically mentions the automatic & manual trim detail and that it looks "chilling". To me it looks like whatever the pilots are doing, the software/autopilot is doing the opposite.

@HillView Aviator is this something you can shed more light on?
Chilling is the right word, and also entirely consistent with what is leaking from the Ethiopia crash: captain-side stick shaker on immediately after takeoff, airplane trimming itself into the ground. Note also that it seems the pilots had some idea of the issue: they retracted the flaps and then tried re-engaging them. And it looks like it flew much better with the flaps down...
 
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Just picked this up from the PPRuNe forums. Its parameters from the Lion Air crash. The person who posted it specifically mentions the automatic & manual trim detail and that it looks "chilling". To me it looks like whatever the pilots are doing, the software/autopilot is doing the opposite.

@HillView Aviator is this something you can shed more light on?
We have been told that the pitch trim can be overridden manually by firmly holding the trim wheel, and that the power to the trim can be removed with the stab trim disconnect switches. It seems this information may not have been known by the pilots.
 

Bishop Boy

Striker
That trim trace is scary, looks like something is playing with them, you turn it off, I'm going to turn it back on.

Can't imagine how the crew felt knowing this was all going wrong.
 

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