I actually typed my response without seeing your reply (you submitted it while I was typing) but it is a somewhat clear example of what I’m talking about...ok...say it....racist comments.
Then is was a solution to a problem that doesn't exist.
What? Just because a problem hasn’t occurred and isn’t likely to occur doesn’t mean you don’t provide a solution. Furthermore it did provide a “solution” to the problem of maintaining the 737 type commonality. Whether or not that is a desirable thing to solve and whether or not MCAS is the best solution is another discussion.
I doubt I can find it, but in one of the articles I read, it was either one of the union guys or an airline executive who said they had studied it and found exactly zero MCAS activations in US fleets. Which makes sense - why should you be slow with no flaps and a high angle of attack in a 737? I've thought from the beginning that in the end there will be an environmental aspect to both of these accidents. Extremely high DA in both places, plus throw in dust and sand in Addis Ababa.
That's a new insight, and plausible.
And even with that light, if pilots aren’t even informed that MCAS exists and how it works and it’s limited fault tolerance, they would not be able to deduce the possible consequences of an AOA disagree.
My intent was to say we expect an ATP to be able to meet minimum qualifications and we need to design to that minimum. What's the old saying? What do you call the guy who graduates last in his medical school? "Doctor". Similar with an ATP. What happens if that minimum starts to drop? Not that the PTS, or whatever, requires lower standards, but the candidates are edging closer to the bottom edge.
I'm not talking zero "incidents", I'm talking zero activations of MCAS in US fleets.The birds in the US know better than to hit our AoA vanes.
There have also been zero incidents in China, Canada, Turkey, Germany, Ireland, India, Japan, the Czech Republic, Singapore, Kazakhstan, Morocco, Qatar, Norway, Mauritania, Iceland, Brazil, Dubai, Fiji, Poland, Panama, South Africa, Mexico, and Argentina... All countries that also have airlines that have taken deliveries of the 737 Max.
But we're Americans, our pilots are better than all those. USA! USA!
The extra cost option was for an AOA disagree light as has been stated many times in this thread. AOA cross checking and redundancy for MCAS purposes was not available, although is slated to be implemented in a future Boeing software update.
In the case of an unschedule MCAS activation due to faulty AoA data then each activation will run for the full 9.3 seconds unless interrupted by either the use of primary electric trim or the stab trim switches being selected to cutoff.
It's not the trim wheel that you're trusting, or not. It is the repeated need to retrim the airplane nose-up. Every time you re-trim the airplane it is going out of trim again five to ten seconds later. After a few cycles, you should know that you have a trim runaway. The problem, on the accident flights, was that the crews (F/O on Lion Air, Capt on Ethiopian) were not retrimming each time so they didn't detect the repeating pattern and arrest the trim problem before it had run the trim to nearly full nose-down.
Only if the stab trim is already at the extreme end of its range and, even then, not impossible; difficult.
Why would you retract the flaps when you have a stick shaker (stall warning) going off?
It does not because is presumes that the pilots have been flying the airplane instead of allowing a malfunctioning system to run the trim to the nearly full nose-down position.
They did. Stick-shaker at liftoff, unschedule MCAS activation at flap retraction. All three flights.
So based on all that, it sounds like the first crew error was retracting the flaps with the stick shaker going off. Once that error was made, the situation could still have been salvaged by making sure that the airplanes were properly re-trimmed each time the primary electric trim was used, and once it was realized that there was a trim runaway, making sure that the airplanes were at least approximately trimmed when the stab trim switches were selected to cutoff. Do I have that right?
I wouldn't say that retracting the flaps was an error, especially not for the first crew. It's just something that I wouldn't do. Just seems a little strange that they would retract them with a stall warning going off.
And as being discussed elsewhere, part of the "flying the aircraft" would have been to reduce power. It is reported that the engine power settings where kept at takeoff levels through the entire sequence. Not only did this add air flow pressure to the out of trim condition but brought them to the maximum maneuvering speed rather quickly, instead of giving them option of proceeding at the minimum air speed to work the nose down problem.
The purpose of trying to figure out whether doing something differently could have saved the flight is to learn, not to lay blame.
Engine thrust is below the cg, so I'd suspect more thrust may have made things better.
Most of this thread has been a pretty good analysis. We've all seen "Well, if they would have only...", a lot. But they didn't, and the "why" is where the learning comes in. "They" could be the crew's decisions and the Boeing design decisions.
I don't think so. The pitch-up from full thrust isn't all that much. They were flying roughly 150kts faster than they needed to, though, which adds a lot of authority to the mis-trimmed stabilizer and increases the air loads on it making manual trimming much more difficult. I think the excessive airspeed was a lot bigger problem than the nose-up moment from thrust was a help.
I think the exact opposite. The speed was helping them.
Perhaps. But as stated elsewhere by flying 737 pilots the excessive engine power on a severly out of trim 737 will get you down quicker than up over an obstacle. Their examples point to if the 302 crew had throttled back to 80% or 75% with flaps 1, they could have retrimmed and dealt with the miscompare air data. Fly the aircraft is was their main point. Same as the Lion pilot did before handing off controll to the SIC. They also state that selecting engine power at 75% and flaps 1 would have removed the mcas and allowed the option of manual trim that wasn't readily possible at 94% engine power.
