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Ethiopian 737 MAX 8 crash

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Ethiopian 737 MAX 8 crash

Old 03-18-2019, 04:56 AM
  #301  
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Originally Posted by sourdough44 View Post
What would of happened if they left the flaps down longer, 1-3000’+ AGL, and done much of the climbout without the autopilot? Of course we’ll naturally keep that nose parked up to control airspeed.


Those 2 things and we wouldn’t be talking about this.

I know, hindsite is easy.
MCAS doesn’t work with the autopilot on. The whole point is to avoid pitching nose up at high AoA when hand flying. Also, if this is the same thing as the Lion Air incident autopilot was probably not an option.

The flight the night before the Lion Ait crash had stick shaker start at rotation, with associated stall warnings which leads one to believe the airspeed is unreliable. Once they climbed away and raised the flaps, MCAS started trimming nose down. The crew the night before used the stab trim cutout switches and landed.
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Old 03-18-2019, 05:55 AM
  #302  
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Originally Posted by F4E Mx View Post
Seems like a bigger horizontal stabilizer with a bigger elevator or maybe replace both with a stabilator would be the definitive fix. The first would be expensive, the second really expensive, but either solution would be cheaper than what is going to be spent resolving these two accidents. Saying you are going to fix the problem by wiring in another AOA indicator and adding some more software just seems unacceptable.

When Beech was developing the King Air series throughout the years the FAA required three separate Type Certificates as the models grew and became more complex. Maybe the MAX needs to start from scratch.
Software update to the MCAS is like a band-aid solution for a band-aid solution. The 737 has grown too much to fit in the original type, IMO. The elevator should be redesigned to be able to overpower the full nose down stab trim as well as full nose up stab trim in a stall. Then there is no need for MCAS.
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Old 03-18-2019, 08:44 AM
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Originally Posted by nfnsquared View Post
Nope, not there either...
Yes it is, and it's been in several other media reports (which admittedly probably came from the same wire report).
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Old 03-18-2019, 08:45 AM
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Originally Posted by sgrd0q View Post
Software update to the MCAS is like a band-aid solution for a band-aid solution. The 737 has grown too much to fit in the original type, IMO. The elevator should be redesigned to be able to overpower the full nose down stab trim as well as full nose up stab trim in a stall. Then there is no need for MCAS.
That would take a long time and cost a vast amount of money, to develop, certify, and then retrofit. Even more money due to grounding losses from all the airlines that have the MAX. Would stall and possibly break the MAX program.

Dollars to donuts they come up with a better bandaid.
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Old 03-18-2019, 09:33 AM
  #305  
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Originally Posted by rickair7777 View Post
Yes it is, and it's been in several other media reports (which admittedly probably came from the same wire report).

Reading comprehension fails one of us. Where does it say in that link (or any other link) that the jackscrew was found in FULL nose down trim?
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Old 03-18-2019, 12:08 PM
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Originally Posted by nfnsquared View Post
Reading comprehension fails one of us. Where does it say in that link (or any other link) that the jackscrew was found in FULL nose down trim?
Ah, semantics. I don't see where it says that, but what it says is...

"All we can say definitely is that the trim was in a position similar to the position found on the Lion Air airplane"

So if not full down, seriously out of trim in the nose down direction, of a magnitude known to have caused the plane to crash once before.
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Old 03-18-2019, 02:29 PM
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At one time Boeing was looking at developing a lighter weight 757. Think the number of passengers was to be about the same as the MAX is now. Not sure the MAX is really fixable without major airframe design changes. By the time you made those changes you would have.......a lighter weight 757.
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Old 03-18-2019, 02:55 PM
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Originally Posted by F4E Mx View Post
At one time Boeing was looking at developing a lighter weight 757. Think the number of passengers was to be about the same as the MAX is now. Not sure the MAX is really fixable without major airframe design changes. By the time you made those changes you would have.......a lighter weight 757.
The MAX will most likely be “fixed” with a software update and zero airframe modification.

But hey maybe you’re right and they’ll test and then retrofit new wings, landing gear, tail, and cockpit onto hundreds of planes to make “a lighter weight 757”.
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Old 03-18-2019, 03:01 PM
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My guess:

1. Comparator logic, so that MCAS uses data from BOTH AoA vanes. In the event of disagreement, it would either be inhibited, or an alert. Possibly a disable-switch added.

2. Mandatory sim-training where the MCAS runs away.

3. I think it will happen in phases. AoA mod will happen quickly...I believe it’s there, just needs to be modded in the software.

A disable switch would take a year to get delivered airplanes modded. New would include it.

Sim training: they’ll give them six months to train everyone.

Flying again by May 15.

Just a guess.
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Old 03-18-2019, 03:22 PM
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Originally Posted by F4E Mx View Post
At one time Boeing was looking at developing a lighter weight 757. Think the number of passengers was to be about the same as the MAX is now. Not sure the MAX is really fixable without major airframe design changes. By the time you made those changes you would have.......a lighter weight 757.
They are seriously looking at doing that right now. But a bigger plane, it would overlap perhaps the top end of the 737 range in pax but will have much longer range. Different plane for a different market niche. But they can't just cancel the MAX and tell everyone to buy a larger, more expensive plane which they haven't even designed yet... everyone would just buy NEOs instead. From a pilot and pax perspective, that would be great. From an American perspective, that would constitute a massive loss in US export dollars.

Still not clear if the NMA will even be launched, but it's looking highly possible in the next year.
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