Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi - Impact on Boeing 737 MAX

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737MAX
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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by 737MAX » 11 Mar 2019, 18:15

Bracebrace wrote:
11 Mar 2019, 15:55
737MAX wrote:
11 Mar 2019, 13:51
MCAS or not, the way "unreliable airspeed" and "runaway stabilizer" should be treated remains the same.
That's a very confusing post...

Unreliable airspeed asks for a specific pitch target (pitch change using the yoke) and throttle selection (thrust change) and no actions with the trim system itself. You don't interfere with the trim system itself.

Runaway stabilizer on the other hand calls for yoke to regain control and activate the yoke cutout switches (no specific pitch target), AT disconnect (no thrust change) and further actions dealing with the trim system itself to de-activate it's function partially or completely.

Two completely different procedures. What goes first? Or only one? Confusing.

If this is the second crash, it is pretty clear there is a problem with the "failure identification". Confusion again.

If the thing is in there, pilots should be informed and have a function demo so they can at least identify what is happening. Confusion is not a problem behind a desk if you have hours and hours to study the case. Confusion is to be avoided at all times inflight. Confusion about failures, confusion about procedures, .... not good.
Huh? Such a situation is clearly confusing, but my post isn't.

Two different procedures, indeed, but both came together in the Lion Air crash, AFAIK.
They had erroneous airspeed + attitude indications and runaway stabilizer.

If you have both problems, you apply both checklists. There is nothing that prevents you to do so.

737MAX
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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by 737MAX » 11 Mar 2019, 18:16

sn26567 wrote:
11 Mar 2019, 15:23


At the time, the cockpit crew were not sufficiently informed of MCAS. Ethiopian pilots should have known by now!
Again, MCAS or not, the procedures are the same !

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by 737MAX » 11 Mar 2019, 18:26

Themax wrote:
11 Mar 2019, 18:04

If you're dealing with both problems, then do both procedures. Personally I would deal with the IAS disagree first, disconnect autopilot, autothrottle, turn off flight directors and fly the aircraft in pitch/thrust until you identify the malfunctioning airspeed indication.

While flying manually (or on autopilot), if there is uncommanded stabilizer movement, then you're dealing with a stab trim runaway --> apply memory items. Basically, disconnect all automatics, if the problem persists, switch the trim off with both cutout switches, and if the problem still persists, grasp the trim wheels manually.

The MCAS system has no "mechanical output" or doesn't "push the nose down", it only gives commands to the stabilizer trim actuators while flying manually. So you see your trim wheels starting to turn nose down, to compensate you will progressively need to pull harder on the yoke, and the movement continues until you don't have any more pitch autorithy to counteract this trim input. Pressing a trim switch on your yoke will inhibit the MCAS system for a few seconds. And if the system still doesn't stop --> stab trim runaway checklist -> kill stab trim inputs.

This was the issue for the Lionair accident. A Boeing bulletin has been issued to inform all crews of the possible issue and the procedures to counteract this issue (what I explained above).

Let's not speculate about what happened to the Ethiopian, as there is no information yet. There are many possible problems can cause trouble maintaining a steady climb after take off.

Greetings from a MAX flyer.
The other issue in the industry is that many airlines discourage manual flight. Some pilots count way too much on automation and are therefore weak in manual flight skills. Good luck to recover from such a situation (unreliable airspeed + runaway stabilizer) if you basically never fly manually (or only when the plane is perfectly in trim and on speed...).

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by Themax » 11 Mar 2019, 18:34

737MAX wrote:
11 Mar 2019, 18:26
The other issue in the industry is that many airlines discourage manual flight. Some pilots count way too much on automation and are therefore weak in manual flight skills. Good luck to recover from such a situation (unreliable airspeed + runaway stabilizer) if you basically never fly manually (or only when the plane is perfectly in trim and on speed...).
I completely agree !

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by jan_olieslagers » 11 Mar 2019, 18:47

A bit of good news among all the misery: one passenger arrived two minutes late and was refused boarding - he may thank his stars!

http://www.spiegel.de/panorama/gesellsc ... ml#ref=rss

737MAX
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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by 737MAX » 11 Mar 2019, 19:10

Inquirer wrote:
11 Mar 2019, 14:18


Is the MAX indeed taking the 737 platform itself too far out of its comfort zone?
Is that why the MCAS is there, to help keep this plane fly safely?
Shouldn't MCAS have been designed far more intelligently then, like on the competing Airbus planes?
To me MCAS seems more like something an undergraduate came up with than a certified solution to a life-threatening weakness in the design by a global aviation firm like Boeing!
You definitely have some points.
The 737MAX is "just" another update of an old 737.

While Airbus could perfectly do that with their A320, I was very disappointed to see Boeing updating their 737 again, again and again... The A320 was already a modern plane, while the 737 is still based on an old thing. And it was about time to start something new to compete with the A320. Too expensive, too slow, and too demanding, I guess... :cry:

That said, it doesn't make the 737MAX unreliable and unsafe either. I'd probably change my mind if the Ethiopian crash has similar causes than the Lion Air one...

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by Luke777 » 11 Mar 2019, 20:19

Can we simplify all this information to the following or not: In the hard competition for more fuel efficient acft, Boeing equipped it's 737 with a big new eco engine that actually didn't quite fit very well on the existing 737 concept, they encountered some negative consequences and had to work around these by means of adding extra software that was able to counteract these consequences...

Bracebrace
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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by Bracebrace » 11 Mar 2019, 20:21

Themax wrote:
11 Mar 2019, 18:04
If you're dealing with both problems, then do both procedures.
How can you identify correctly if you want to shut down a system that protects you at low airspeeds (close to stall angle of attacks) and be able to identify an airspeed unreliable situation? The system is supposed to work in low airspeed scenario's. It opens huge doors to negative training.

I'm waiting for the first pilot to shut down the (in this case correctly working) system on an ILS after a glide approach and allow the aircraft to fall down to planet earth aiming for 10° pitch up and 80% N1 (whatever the values on the MAX), shutting down the nose down trim, all while he doesn't realise what is actually happening...

But indeed, this is the Indonesian crash.

737MAX
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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by 737MAX » 11 Mar 2019, 20:27

Bracebrace wrote:
11 Mar 2019, 20:21
Themax wrote:
11 Mar 2019, 18:04
If you're dealing with both problems, then do both procedures.
How can you identify correctly if you want to shut down a system that protects you at low airspeeds (close to stall angle of attacks) and be able to identify an airspeed unreliable situation? The system is supposed to work in low airspeed scenario's. It opens huge doors to negative training.

I'm waiting for the first pilot to shut down the (in this case correctly working) system on an ILS after a glide approach and allow the aircraft to fall down to planet earth aiming for 10° pitch up and 80% N1 (whatever the values on the MAX), shutting down the nose down trim, all while he doesn't realise what is actually happening...

But indeed, this is the Indonesian crash.
If you are at the controls, bracebrace is definitely the right username for all your passengers! :lol:

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by Bracebrace » 11 Mar 2019, 20:43

Touché :-)

I know, at least I warned them lol ;-)

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by luchtzak » 11 Mar 2019, 21:34


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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by luchtzak » 12 Mar 2019, 01:24

Two more to the list:
  • GOL Linhas Aéreas
  • Aeromexico

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by luchtzak » 12 Mar 2019, 01:25

#update Senator Diane Feinstein to FAA—ground the Max: “Until the cause of the crash is known and it’s clear that similar risks aren’t present in the domestic fleet, I believe all Boeing 737 Max 8 series aircraft operating in the United States should be temporarily grounded”

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by luchtzak » 12 Mar 2019, 07:24

  • SpiceJet and Jet Airways, but at least 1,000 hours experience on the type for a captain and 500 hours for copilots (Indian civil aviation authorities), Jet Airways' Boeing 737 MAX aircraft are grounded anyway after the non-payment of lease rentals
  • Civil Aviation Authority of Singapore (CAAS), affecting SilkAir (6)

telspace2005
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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by telspace2005 » 12 Mar 2019, 07:46

luchtzak wrote:
12 Mar 2019, 01:24
Two more to the list:
  • GOL Linhas Aéreas
  • Aeromexico
I am so relieved ! Good news.

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by luchtzak » 12 Mar 2019, 08:29

“Ever since the Lion Air crash, Boeing has been developing a flight control software enhancement for its Boeing 737 MAX type, designed to make an already safe aircraft even safer,” the U.S. aircraft manufacturer announced. The FAA says it anticipates mandating this software enhancement with an Airworthiness Directive (AD) no later than April. Boeing have worked with the FAA in development of this software enhancement.

The update includes updates to the Maneuvering Characteristics Augmentation System (MCAS) flight control law, pilot displays, operation manuals and crew training. The enhanced flight control law incorporates angle of attack (AOA) inputs, limits stabilizer trim commands in response to an erroneous angle of attack reading, and provides a limit to the stabilizer command in order to retain elevator authority.

https://www.aviation24.be/manufacturers ... -max-type/

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by Acid-drop » 12 Mar 2019, 08:31

What is TUI waiting ?
My messages reflect my personal opinion which may be different than yours. I beleive a forum is made to create a debate so I encourage people to express themselves, the way they want, with the ideas they want. I expect the same understanding in return.

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by Acid-drop » 12 Mar 2019, 08:36

luchtzak wrote:
12 Mar 2019, 08:29
“Ever since the Lion Air crash, Boeing has been developing a flight control software enhancement for its Boeing 737 MAX type, designed to make an already safe aircraft even safer,” the U.S. aircraft manufacturer announced. The FAA says it anticipates mandating this software enhancement with an Airworthiness Directive (AD) no later than April. Boeing have worked with the FAA in development of this software enhancement.

The update includes updates to the Maneuvering Characteristics Augmentation System (MCAS) flight control law, pilot displays, operation manuals and crew training. The enhanced flight control law incorporates angle of attack (AOA) inputs, limits stabilizer trim commands in response to an erroneous angle of attack reading, and provides a limit to the stabilizer command in order to retain elevator authority.

https://www.aviation24.be/manufacturers ... -max-type/
What a bad PR !!
They basically say that the crash of this week could have been avoided !!
My messages reflect my personal opinion which may be different than yours. I beleive a forum is made to create a debate so I encourage people to express themselves, the way they want, with the ideas they want. I expect the same understanding in return.

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by luchtzak » 12 Mar 2019, 08:47

Acid-drop wrote:
12 Mar 2019, 08:31
What is TUI waiting ?
André Berger, Flight Operations director, flight instructor and TRI/E B737/767/777/787 of TUI fly Belgium wrote: We operate a fleet of #B737max8 for more than a year and can only say it performed excellently from a safety, operational and customer satisfaction perspective.

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Re: Ethiopian Airlines Boeing 737 MAX crashes between Addis Ababa and Nairobi

Post by luchtzak » 12 Mar 2019, 09:10

Unconfirmed: Australian CAA to ban 737 MAX from its airspace.

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