Ethiopian 737 MAX 8 crash
04-07-2019, 11:28 AM
#551
Gets Weekends Off
Joined APC: Jul 2017
Position: CRJ9 CA
Posts: 4,083
Originally Posted by Chris Close
I have a question. Perhaps a stupid one. And please humbly disabuse (and kindly if you can manage it, though I will not take it personally if this is beyond your abilities, a situation I myself have encountered and failed at, though I endeavour to better myself) me of my ignorance if it is a stupid one. If at or near VMO at that density altitude, with full down trim on the horizontal stab, what back pressure on the yoke is required to maintain level flight? Let alone climb? Is it even possible to maintain altitude under this configuration? Has anyone replicated this situation in a sim? Might it be worth understanding the aircraft's flight characteristics in this particular flight regime before passing judgment on the deceased's attempts to remedy the situation they were presented with?
04-08-2019, 06:09 AM
#554
Gets Weekends Off
Joined APC: Jan 2006
Posts: 222
Originally Posted by Mesabah
Yes, reduce speed, add flaps, situation over. The procedure didn't call for either unfortunately.
04-08-2019, 11:38 AM
#555
New Hire
Joined APC: Apr 2019
Posts: 6
Originally Posted by Mesabah
Yes, reduce speed, add flaps, situation over. The procedure didn't call for either unfortunately.
Also it's mentioned somewhere that with autopilot engaged, MCAS should not be activated (not sure if it's true or not). Shouldn't that be the obvious choice (engage autopilot) and/or continuing the use the electric trim to get the nose up and stabilize the airplane.
It appears the autopilot was briefly engaged but then disengaged in this crash.
Too many what ifs and should have's in this stressful situation that no doubt are the factors with the initial trigger to bring this to a disastrous conclusion.
04-08-2019, 12:09 PM
#556
Line Holder
Joined APC: Apr 2007
Position: GA pilot
Posts: 38
MCAS is software. Unlike fundamental aircraft design, there is a lot of flexibility. Coding MCAS so that it could put the aircraft in a situation where the pilots were struggling with yoke back-pressure is a failure of software engineering. Sure, nudge the trim down near a supposed stall, but set some limits.
This is a Boeing failure, pure and simple. The most important part of the fix that Boeing is proposing to MCAS is limit the amount of AND trim that MCAS can produce.
A bad software design killed hundreds. I have no sympathy for those arguing that maybe if the pilots were faster or smarter they might have pulled it out. No situation that bad should ever have presented itself to them.
Signed,
An aviation software engineer and GA pilot
This is a Boeing failure, pure and simple. The most important part of the fix that Boeing is proposing to MCAS is limit the amount of AND trim that MCAS can produce.
A bad software design killed hundreds. I have no sympathy for those arguing that maybe if the pilots were faster or smarter they might have pulled it out. No situation that bad should ever have presented itself to them.
Signed,
An aviation software engineer and GA pilot
04-08-2019, 01:36 PM
#557
Gets Weekends Off
Joined APC: Apr 2016
Position: 767
Posts: 133
Originally Posted by aaatwood
I have no sympathy for those arguing that maybe if the pilots were faster or smarter they might have pulled it out. No situation that bad should ever have presented itself to them.
04-08-2019, 01:55 PM
#558
Disinterested Third Party
Joined APC: Jun 2012
Posts: 6,026
Originally Posted by aaatwood
No situation that bad should ever have presented itself to them.
The crew took it there.
No crew should have ever taken the airplane there.
No crew should ever take the airplane to a point where MCAS is required, either.
If MCAS activates without being in that region, however, it is controllable, it is stoppable, and the aircraft is flyable.
It may be the difference between who occupies the front office: a pilot or a passenger.
04-08-2019, 02:28 PM
#559
Gets Weekends Off
Joined APC: Nov 2016
Posts: 936
Originally Posted by JohnBurke
It didn't.
The crew took it there.
No crew should have ever taken the airplane there.
No crew should ever take the airplane to a point where MCAS is required, either.
If MCAS activates without being in that region, however, it is controllable, it is stoppable, and the aircraft is flyable.
It may be the difference between who occupies the front office: a pilot or a passenger.
The crew took it there.
No crew should have ever taken the airplane there.
No crew should ever take the airplane to a point where MCAS is required, either.
If MCAS activates without being in that region, however, it is controllable, it is stoppable, and the aircraft is flyable.
It may be the difference between who occupies the front office: a pilot or a passenger.
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