737 grounded???

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Aerowerx

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Another "bottom of the hour" news report.

Evidently, Canada has grounded all Boeing 737 Max (whatever that is).

That is all they said. What's this about?
 

DangerZone

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Could be software. Like, some pilots soft were. Pilots who are not that soft could continue to fly after switching the freaking autotrim and autopilot off.

If anyone wodered what the pilots could have done, the following video might provide a hint or two.

 

Swampyankee

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Could be software. Like, some pilots soft were. Pilots who are not that soft could continue to fly after switching the freaking autotrim and autopilot off.

If anyone wodered what the pilots could have done, the following video might provide a hint or two.

Yes, if they had been told how to do so. The reports are that they were not.
 

DangerZone

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Yes, if they had been told how to do so. The reports are that they were not.
You're right about that, many pilots are not taught to Aviate first. You know, the simple 'old school' - Aviate, Navigate, Communicate. The problem nowadays is that many are expecting to be told to do something instead of using common sense and making decisions. Remember Sully? That guy is my hero. Even though he was told to do something else, he used common sense and landed on the Hudson.
 

BJC

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Yes, if they had been told how to do so. The reports are that they were not.
Even private pilots know how to determine if an unexpected pitch down (or up) is valid, and then to immediately disable auto trim and or the autopilot.

I’m not trying to make the case that there was no need for better information on the 737 Max MCAS to be provided to pilots transitioning to the Max. I am saying (and agreeing with DZ and others here) that a competent pilot should be able to deal with a failure of the MCAS without specific training.

I’m also not saying that a MCAS failure was the root cause of either crash. Those causes are yet to be determined, AFAIK.


BJC
 

markaeric

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I didn't know the trim wheels were that visible on a 737, nor that there were permanent cutout switches (only heard about momentary disengage). But why even have MCAS at all? If the aerodynamic tendency of the Max 8 is to pitch up under certain conditions can be counteracted by a relatively slow stab trim, why not just warn the pilot instead the same way approaching stall always is; via stick shaker and CAS/alerts/AoA indicator? Was it really so important to maintain the feel of previous 737 versions?
 

DangerZone

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I didn't know the trim wheels were that visible on a 737, nor that there were permanent cutout switches (only heard about momentary disengage). But why even have MCAS at all? If the aerodynamic tendency of the Max 8 is to pitch up under certain conditions can be counteracted by a relatively slow stab trim, why not just warn the pilot instead the same way approaching stall always is; via stick shaker and CAS/alerts/AoA indicator? Was it really so important to maintain the feel of previous 737 versions?
Remember the Air France flight from Brasil to France when two pilots stalled a fully operational Airbus from FL 380 all the way down to the ocean surface? They stalled the aircraft for 3 minutes and 30 seconds before the older captain entered the cockpit and realized what the two copilots were doing. It was too late by then, the aircraft did not have enough altitude to recover.

https://en.wikipedia.org/wiki/Air_France_Flight_447

The MCAS was supposed to prevent pilots from stalling a perfectly good airplane. I guess it was not meant to be idiotproof, but let's wait for the final report and experts to determine the exact cause. From what I heard the MCAS was supposed to allow easier pitch down when full power is added with the more powerful Max 8 engines. This might lead to PIOs if a novice pilot is not used to the autocorrection system.

Every pilot should be strong enough (and slightly headstrong, too) to switch the autopilot and autotrim off the moment he/she realizes the aircraft has a nasty tendency to pitch down into the ground. The kid flying the Ethiopian 737 Max 8 had around 200 hours, and I bet it was all integrated instead of modular. In such a situation, one has to think fast and act immediately, experience is a good thing to have.

There is a shortage of pilots worldwide. Both pilots of the crashed jet were in their twenties. The one flying had around 200 hours, possibly a minimum of around 150 hours of aircraft and the rest on simulators. It is very likely he was not trained for such a situation. It is possible he never experienced some aircraft system malfunction on board, he probably never had to override and fly manually before.
 

Voidhawk9

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and then to immediately disable auto trim and or the autopilot.
Every pilot should be strong enough (and slightly headstrong, too) to switch the autopilot and autotrim off the moment he/she realizes the aircraft has a nasty tendency to pitch down into the ground.
You both may have missed it - MCAS is active only when the autopilot is off! So likely in the pilot's minds, they had already deactivated any automatic flight control inputs. Plus, MCAS is an intermittent input. It's a human factors nightmare, really.
 

BJC

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You both may have missed it - MCAS is active only when the autopilot is off! So likely in the pilot's minds, they had already deactivated any automatic flight control inputs. Plus, MCAS is an intermittent input. It's a human factors nightmare, really.
My comment, quoted above, was not about MCAS, but was about unexpected pitch trim or control action, and any pilot’s response.

My understanding is that when MCAS trims, it operates through the standard trim system and the manual trim control wheel turns. That would be an indication of what was causing an uncommanded nose down force.


BJC
 

Vigilant1

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The MCAS was supposed to prevent pilots from stalling a perfectly good airplane.
I think it might be more accurate to say that the MCAS was designed to give the 737 MAX the same "feel" and trim requirements as earlier 737 models. This facilitated certification under the existing tyoe rating and also reduced crew training requirements. Without MCAS, the plane would be no more dangerous than any other 737 when hand-flying. Add power and you might need to retrim--nothing different there, just the magnitude of the trim.
You both may have missed it - MCAS is active only when the autopilot is off! So likely in the pilot's minds, they had already deactivated any automatic flight control inputs. Plus, MCAS is an intermittent input. It's a human factors nightmare, really.
But there are trim malfunctions in non-MCAS aircraft that are not far off (trim cycles back and forth from stop to stop). Or other failures (intermittent switch?). The memory procedure for any trim anomaly is the same, and they all work with an MCAS malfunction (incl one caused by a faulty AoA sensor).
 

davidb

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You both may have missed it - MCAS is active only when the autopilot is off! So likely in the pilot's minds, they had already deactivated any automatic flight control inputs. Plus, MCAS is an intermittent input. It's a human factors nightmare, really.
There’s two other auto trim modes (auto trimming with the autopilot off) that have been moving the trim for the last 25 years that I know of. The reason we have the runaway stab trim procedure is because it has always been a possibility with the autopilot on or off. This new mode certainly needs the forthcoming improvements but I wouldn’t go so far as to call it a nightmare. We really need the cvr info to analyze the human factors.

I want to know why one crew can successfully handle the malfunction while another crew crashes for the same malfunction. Sure, it’s important to have the safest design possible. I say it is just as important to have the most capable crew possible. I say we save half the stones for training and qualification programs.
 

Kyle Boatright

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Even private pilots know how to determine if an unexpected pitch down (or up) is valid, and then to immediately disable auto trim and or the autopilot.
I could make a case that the MCAS accidents and the Air France accident all happened because of a lack of a thorough understanding of some fundamentals of flight. They may have understood "If A, then B." but maybe weren't comfortable outside of trained or canned scenarios.
 

BBerson

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If both pilots are pulling back with all their might do they need a third pilot to crank the trim back up?
 

TFF

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Training. Sim training is constant damage control. Flying the plane with big things broken without flying with a real broken airplane. It seems that many of these advanced flying system airplanes are bought by companies in countries that are hoping the smart plane can cover the low time pilots they have to hire. Do these guys go to sims? I bet many don’t, and the get the pilot jobs because of family status not skill. There is a problem with the Max. US pilots were taught to deal with the problems even if they should not be there. These foreign pilots clearly are relying on the plane and not training. AOA vanes and pitot tubes break. I have changed plenty when I work at a regional. When they are primary inputs for a flight controlling computer, they have to work or the plane will crash. Pilots don’t have a choice then.
 

davidb

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If both pilots are pulling back with all their might do they need a third pilot to crank the trim back up?
I suspect you are coyly referring to the fact that a jump seat pilot helped in the previous flight. That is a salient point. It’s not the first time a jump seater saved the day from their unique perspective. It’s a lot easier to analyze the situation from that seat.

The situation doesn’t require a third person to crank the trim but it does require a pilot to recognize the situation and not allow the trim to runaway to the point of both pilots needing to pull back with all their might. The trim wheel gets progressively harder to turn when one is pulling harder on the yoke.
 
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