Originally Posted by
bill fly
Also Memberberry and Derfed,
This illustrates my point that the stab runaway checklist is unsuitable for the false MCAS operation case. Point two in the stab runaway checklist presumed that AP was on and that AP trim was the trouble maker, if runaway stops after disconnecting, so now try thumb trim etc.
You can’t just pick bits out of a drill and say “I’ll use this point now”.
What is needed is a QRH checklist with memory items to cover the specific fault, including possible accompanying distracting indications.
As MCAS logic is in the process of being modified, a checklist which might have covered the two fatal cases may well not be suitable for the new mod.
What these men were faced with was a checklist for a different situation, nevertheless recommended by Boeing - no time to reflect on its merits and no ground study of any other suitable procedure.
We can all sit here and sort out measures at our leisure, which those pilots couldn’t.
A new and case specific drill needs to be made before further ops.
Precisely.
Reading the emergency AD and revised runaway trim checklist issued after the Lion Air accident it is hard to avoid a conclusion that it was carefully crafted to address the newly revealed MCAS system while preserving the 'party line' that the existing checklist would have worked, hence no blame to Boeing.
Especially for english as a second language crews it would be difficult to 'read between the lawyerse lines' to extract the needed critical information, only some of which was in a 'note' not part of the flow.
Had a new clear and forcefull MCAS misbehave checklist been issued at that time we almost certainly would not be 3500 posts into a discussion of an event that cost 157 lives and billions of dollars.
Plenty of good suggestions here so I will add just one for what should have been in the checklist:
In case of a suspected MCAS issue momentary activation of up then down trim every 3 seconds will effectively disable the MCAS system.
The trim and other issues can be addressed in the normal manner while this sequence is continued.