[quote author=Colonel Sanders link=topic=9535.msg27340#msg27340 date=1553607931]
I would strongly suspect that this is going to be added
to the sim training, as part of BA's upcoming changes.
[/quote]
Funny how when they fully disclose the system and train the pilots on how to recognize and deal with it, it becomes easy!
Gerry
Re: 737 max groundings.
Posted: Wed Mar 27, 2019 3:22 am
by cgzro
Would not both of these accidents have had the same results had the problem been a real run-away nose down trim after take-off? Eg .. Say the pilot's nose down control column trim button got stuck? Isn't the procedure to deal with a real run away trim the same as the MCAS triggered nose down trim? Actually I'd have thought a real runaway nose down trim would be worse because it won't pause and restart so you'd have even less time to correct it.
Having said that it does seem silly to have a single AOA input as the driver when there are two that could be queried to ensure they are in approximate agreement.
Would not both of these accidents have had the same results had the problem been a real run-away nose down trim after take-off? Eg .. Say the pilot's nose down control column trim button got stuck? Isn't the procedure to deal with a real run away trim the same as the MCAS triggered nose down trim? Actually I'd have thought a real runaway nose down trim would be worse because it won't pause and restart so you'd have even less time to correct it.
Having said that it does seem silly to have a single AOA input as the driver when there are two that could be queried to ensure they are in approximate agreement.
[/quote]
Full nose down stabiliser cannot be overcome with elevators - look at the difference in surface area between the two. Going to take a lot of turns on the wheel to get the trim back to a semi correct location - all while the aircraft is heading down at increasing speed. You also need to think about that before you disable the stab trim. At low altitude I doubt you'd have the time.
A triple system is the way to go - 2 AOA with different inputs - which one is correct?
An even better option is to start with a brand new design instead of tweaking a 50+ year old aircraft.
Re: 737 max groundings.
Posted: Wed Mar 27, 2019 2:17 pm
by Colonel
[quote]2 AOA with different inputs - which one is correct?[/quote]
Check the news today - BA and the FAA agree with me that MCAS
should look at both AOA and will disengage if they disagree. See
my previous comments.
For example, this one from March 18:
[img width=500 height=326][/img]
Re: 737 max groundings.
Posted: Thu Mar 28, 2019 3:26 am
by cgzro
Agreed, and this is standard practice in safety critical software. When you have multiple systems and one disagrees with the others it is voted out and ignored. If you have two systems that disagree the only thing you can do is disable and ask a human. Kind of redundant software 101.
Re: 737 max groundings.
Posted: Mon Apr 01, 2019 1:24 am
by Eric Janson
MCAS was required for certification.
If the system is disabled then the aircraft no longer meets certification standards.
I'm not sure this 'fix' is going to be accepted quite so easily by the regulators.
They never fixed the battery problems on the 787 either - building a steel box around them with a pipe venting overboard is just laughable imho. I understand the aircraft still has a lot of electrical issues.
Re: 737 max groundings.
Posted: Mon Apr 01, 2019 4:47 am
by ScudRunner-d95
Gee maybe Boeing should have looked a little longer at that clean sheet design,
Kind of reminds me of BBD not taking pause after the CRJ200 and saying "Is this really worth it"
How about that BRJ-X program we just shelved?
I stumbled across this in my wanderings. Just shows how fucked up the media and the propaganda announcements are. What on earth are they talking about when stated that the crew reacted correctly. Ya still need to fly the fucking aeroplane. The guy in the video comes across as having knowledge and not sure how he got the detailed recorder read outs. He was getting thumbs up from 73 max drivers in the comments.