Originally Posted by
Ian W
From the newspaper article above:
The certification process relies on crews 'flying the plane' (see magenta line video) when something goes awry. All systems eventually rely on giving the bag of bolts to the flight crew - that's what alternate and direct law are about in A and it is why the flight crew are there. It was expected that a response to inappropriate MCAS would be autopilot off, autothrottle off, manual trim to correct to neutral trim then stab trim off and fly the plane. Perhaps certification should not rely on the crews following these NNC and other checklists? That is a big can of worms and leads to autonomous aircraft that can handle non-nominal cases that the crew were there to handle.
All three crews
did NOT follow the "Approach to Stall and or Stick Shaker" NNM immediately as required by the QRH with stick shaker activation.
Originally Posted by Boeing 737 QRH
"Immediately do the following at the first indication of stall (buffet or stick shaker).
"smoothly apply node down elevator to reduce the angle of attack until until buffet or stick shaker stops".
If they blindly followed the QRH, there would a couple of smoking holes just off the end of the runway as per my post
#3631. I will say that again, all 3 crews failed to immediately perform the required procedure that Boeing requires. Why was that?
It was as obvious to them, as it is to us that there was something was not right and the safest option was to NOT perform the approach to stall NNM. They had good visibility and excellent Situational Awareness (SA) through the windows to overcome the instinct and urge to lower the nose as everything in their training had taught them to do.
It gets much more challenging when you are dealing with a complex problem, noise and incomplete information, your ability keep SA deteriorates very quickly. Boeing also says in the checklist instructions that only single failures are considered, and the crew have to deviate from procedure(s) in the case of multiple problems.
Originally Posted by Boeing QRH Non-Normal Checklist Instructions
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While every attempt is made to supply needed non-normal checklists, it is not possible to develop checklists for all conceivable situations
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In some multiple failure situations, the flight crew may need to combine the elements of more than one checklist. In all situations, the Captain must assess the situation and use good judgement to determine the safest course of action.
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The Flight Crew must be aware that the checklists cannot be created for all conceivable situations and not intended to replace good judgement. In some situations, at the Captains discretion, deviation from a checklist can be needed
All three crews made a good choice not following the Approach to Stall NNM immediately and kept the aircraft flying. So this is a more complex issue than simply failing to follow a procedure. Sometimes you are required to not follow something. That is the difficult part about flying, deciding exactly what the problem is what to do, or not to do.