211–220 of 347 posts
Earlier quoted context omitted.
MCAS is not an emergency system, it is a trim control system designed to make the plane behave predictably in an otherwise unstable flight regime. If you wanted it to move fast, you would use a stick pusher; moving the trim takes many seconds.
I wonder why Boeing didn't use a stick pusher, then.
>The left Indicated Airspeed increased, eventually reaching approximately 458 kts and the right Indicated Airspeed reached 500 kts at the end of the recording. The last recorded pressure altitude was 5,419 ft on the left and 8,399 ft on the right. How can the sensors record such different readings?
>the First-Officer mentioned Master Caution Anti-Ice.
Earlier quoted context omitted.
Just out of curiosity, will there actually be any punishments handed out beyond just a slap on the wrist? Or is Boeing far too large of a corp to take on?
I've read a couple of these things (strongly recommended — aviation postmortems are a model for us all) and my impression is that "too large" or "slap" are foreign terms in their debugging culture. Their priority list is, AFAICT: 1. Find out what happened. 2. Find out why. 3. Find out how to make sure it doesn't happen again. 4. See point 3. 5. See point 3.
Not that I think that's going to be the result of step 2. It was a contributing factor, probably, but it's not the whole story by any means.
Earlier quoted context omitted.
For comparatively trivial things like what to do when we get too much traffic on servers, engineers do “game day” testing. How does anyone expect pilots to run through these crazy scenarios and perform flawlessly unless they have done it in a simulator many times?
Um, they do? Endless simulator drills of various emergency scenarios is a large part of becoming a pilot and staying certified.
Reading through the chronology in section 1.1, it feels like a movie where the aircraft is a malevolent entity that's trying to kill them. So if I were in the cockpit I'm sure it would've been some mix of fear and anger. My life's not in danger though, so I'm only left with the anger, on their behalf, knowing some greedy bunch of assholes were effectively that malevolent entity, whose will was expressed via the aircr…
Anyway, I'm on your side. Two planes falling from the sky killing hundreds I mean that's a non negligible percentage of 9/11 casualties. Maybe we don't know exactly the cause (tho it seems we do) but at any rate I'd wager a large sum of money that this is boeings fault.
Earlier quoted context omitted.
Being capable of performing a glide without electricity does not necessarily imply that a no-power glide can safely be entered from extreme conditions like diving too fast with trim set to insane.
Why is it possible to set the trim to insane? Is there a legitimate scenario where that would be used?
It appears that Boeing's directive was simply wrong, and doomed them. The right response to faulty MCAS is not to do a stab trim cutout and then manually retrim, but to first use the manual electric trim switches to fix the trim and then immediately do a stab trim cutout. This is mentioned at the end of the directive, but reads more like an afterthought when it should be the standard procedure.
We're now talking about pilots having to have abnormal levels of skill and possibly even strength to fly this aircraft.
That's an untenable state of affairs. Boeing have really screwed this one up.
Am I mistaken or is there a missing item in the chronology where the pilots reactivated the electric stabilizer trim? The timeline mentions stab trim being switched to cutout, and if you look at the FDR graphs there's a (relatively) long period of more-or-less stable trim after that. But then there's an automatic trim down, which is only possible if the electric stab trim is switched back on, and there's no mention o…
The graphs record the AND trim movement even if the electric trim is disabled. You can see that by comparing the pitch trim absolute position to the manual and automatic electronic trim graphs.
Earlier quoted context omitted.
During normal flight conditions, the nose does not pitch up beyond the pilot's ability to control with the elevator, and the pilot doesn't fly especially close to the critical angle of attack. MCAS is for an unusual combination of conditions where both elevator and trim might be needed to reduce the angle of attack. An example would be if the pilot set a fairly high nose-up trim to maintain the slow speed of final ap…
> An example would be if the pilot set a fairly high nose-up trim to maintain the slow speed of final approach, then decided to go around (abort the landing), applied full thrust, and fully raised the flaps too early. This scenario seems it would apply to previous generation 737s as well. But for some reason, MCAS was required for the MAX 800. Everything I have read so far indicates the MAX 800 has some 'pitch up on…
The elevator is not enough to overcome the nose-up pitching moment of the MAX under certain conditions, but the trim is.
Earlier quoted context omitted.
> It's possible that aerodynamic load (of the stabilizer opposing the elevator) made it physically impossible to manually trim given any mistrim at the time the cutout happened, given the airspeed they had. Its been noted in previous discussions that while it would be difficult, the load can be overcome if both pilots were to operate the manual trim wheel at the same time. Not that its a good situation to be in.
> Its been noted in previous discussions that while it would be difficult, the load can be overcome if both pilots were to operate the manual trim wheel at the same time. I haven't seen that noted anywhere, and have seen it theorized as impossible without motor assist, given their airspeed and with the elevator opposing. Got a link?