There is a system for telling the pilot the aircraft speed , this is not macos

There is no o in MCAS

The issue may be a sensor is failing or mcas is failing that’s neither here nor there
The pilot knows his airspeed and should switch off mcas and take control

no, they were not lying in am sure , but they were mistaken not because of the instrumentation in their cockpit
that may or may not  have been correct., that is always the case in any aircraft they would have been flying to that speed , there are always situations were there can be false or faulty readings of course , that is when pilots disengage from autopilot , and should also switch off mcas
And take manual control

It’s seems the pilots may have been confused , I don’t know
It’s a combination of poor design as I said before and pilots not fully understanding the systems , perhaps

and mine before that

my aircraft is unflyable, my instruments are giving me unreliable info, we're pulling 10G and falling like a stone, i've never seen anything like this in my life, it must be mcas ... right

What’s difficult about that ?

I know it’s not simple , it’s complex
That’s the problem , it is the fault of poor design
You don’t bring in computer systems to compensate for fundamental problems in the aircraft design
That’s a disaster waiting to  happen

not what you were saying before, you were saying how come the pilots didn't turn off mcas and recover

can you think of any reasons why they didn't turn mcas off?

im asking you, you seem to know everything

go on surprise yourself ...

"macos" ... genius

I see lfc has trapped someone else.

if him being a fckwit is trapping someone then yes, i'm well and truely trapped

anythings possible detraveller I suppose

This post taken from a 737 pilot on PPRuNe is as good an appraisal of why it's not as simple as just turning MCAS off as I have seen:

Originally Posted by Aloha_KSA  View Post
As a long-time 737 driver I'll just chime-in a few points. Regarding the trim wheel ability to move the stab at high speed from full deflection: I seriously doubt that there would ever be too much force on the elevator that the trim wheel could not move it. There is a lot of leverage in the jack screw, and the turns of the trim wheel make very minute changes to the angle of the stab.

But know that moving from full deflection to neutral would take a painfully long time. On the -200 we used to wind the trim full fore and aft as part of the preflight checks. (We stopped doing that on the NG.) . Using the motor-driven trim this took about a minute to go full forward, full aft, then back to about 4 units. It is not physically possible to wind the trim wheel that fast for that long manually, especially when your aircraft is lurching about like a rodeo bull. Also note that it doesn't take much movement to change the aircraft's attitude significantly, and the aircraft is very controllable using manual trim. Back in the cargo days I once did a 20 minute flight using only the rudder and stab trim and manual power (on the -200) from after flaps up to 10000' on descent. That's right - I didn't touch the yoke, autopilot-off from climb-out to descent. It was very controllable and stable. (That was a good training exercise, too.)

My First Point: If we don't catch this mis-trim early, un-doing it manually will take a very long time and maybe more time than is available when your aircraft is only 1000' AGL. AND to use the trim wheel for more than small changes, one has to fold the handle out. A handle that has injured many a knee in simulator sessions because combined with the trim motor's speedy rotation of the wheel, it can leave one with a permanent limp.

Second: For all the arm-chair Monday morning QB's who are saying: "Oh, they should have recognized it immediately and disconnected the trim:"

(1) Just after takeoff there is a lot going on with trim, power, configuration changes, and as noted above, the darn speed trim is always moving that trim wheel in seemingly random directions to the point that experienced NG pilots would treat its movement as background noise and normal ops. Movement of the trim wheel in awkward amounts and directions would not immediately trigger a memory item response of disconnecting the servos. No way.

(2) The pilots could very reasonably not have noticed the stab trim movement. Movement of the stab trim on the 737 is indicated by very loud clacking as the wheel rotates. On the -200 it was almost shockingly loud. On the NG, much less so. HOWEVER, the 737 cockpit is NOISY. It's one reason I am happy to not be flying it any more. The ergonomics are ridiculous. Especially at high speeds at low altitudes. With the wind noise, they may not have heard the trim wheel moving. The only other way to know it was moving would be yoke feel and to actually look at the trim setting on the center pedestal, which requires looking down and away from the windows and the instruments in a 'leans'-inducing head move. On the 717, for example, Ms. Douglas chimes in with an audible "Stablizer Motion" warning. There is no such indication on the 737.

(3) The fact that they were at high power and high speed tells me the stick shaker was activated. With that massive vibrator between your legs, alternating blue sky and brown out the window, your eye balls bouncing up and down in their sockets as the plane lurches up and down in positive and negative G's, it would have been a miracle if one of the pilots calmly reached down, flicked off the stab servo cutout switches, folded out the trim handle, and started grinding the wheel in the direction of normalcy. These pilots said over the radio that they had "unreliable airspeed". So they did not even know which instruments to rest their eyes on for reliable info. Their eyes were all over the cockpit looking for reliable info, the plane is all over the place like a wild boar in a blanket not behaving in any rational way. And the flying pilot may have been using the tiny standby IFDS for airspeed and attitude. Ouch.

Finally, runaway stab trim is a very, very rare occurence up until now. We trained it about once every other year in the sim because it is so rare. And when we did it was obvious. The nose was getting steadily heavier or steadily lighter with continuous movement of the trim wheel. That is a VERY different scenario than what these pilots faced.

We also trained for jammed stabilizer, the remedy for which is overcoming it with force. The information they were faced with could very reasonably have been interpreted that way, too.

An URGENT AD from the FAA/ Boeing after Lion Air would have helped get it back to the front of the pilot's minds for sure. Extra training by the airline or an urgent pilot memo would have helped. Maybe one was issued, we don't know yet.

A better question might be: given this nose down attitude, high speed, and fully nose down or almost fully nose down stab, how much altitude would they have had to have to be able to recover. I'm thinking at least 10000 feet to recognize the problem, disconnect the switches, fold out the handle and start frantically winding the stab back to normalcy while the flying pilot tries to gain control via the elevator. It's entirely possible that this scenario, if not recognized early on, is unrecoverable at any altitude.

so the question remains is there a switch that disables mcas or not, if not that's a problem right there with the design
With auto pilot it is a matter of the pilot pulling back on the controls quite sharply
that makes sense
If it is complicated and tricky to disable mcas that is a design fault

how can there be a system that gives control of the aircraft to a computer that cannot be brought back under control by the pilot and quickly if not immediately