[sokoloff]

> it should be pretty bloody obvious if dual control is going on.

Yet we have an example here where it wasn't obvious to a (presumably) fully competent crew who got to the point of missing an approach and declaring an emergency for a flight control anomaly that they couldn't diagnose as being the other human 4 feet away from them also being on the controls.

"Should be" obviously wasn't "is" in this case.

Edit to add: Also from the report:

  The following factors may have contributed to the simultaneous inputs on the controls:
  <snipped 5 other bullets> 
  • the conviction that simultaneous inputs on the controls would be quickly perceived by crews on this type of aeroplane.

[traceroute66]

> fully competent crew who got to the point of missing an approach and declaring an emergency

I think you need to re-read the PDF. My reading of it is that the missed-approach decision was made by the PF on the basis of the unstablised approach, and that it is what happened after that decision that is under investigation in this report. Undertaking MAP due to unstable approach is pretty standard stuff that occurs all day, every day.

The report states there were zero force inputs by PM prior to the missed-approach, which correlates with the other note in the report that the PM ghosted the controls in the period following the missed-approach and that is when the apparent reflex action occured.

[sokoloff]

My read is that the approach was not unstable (it met stabilized approach criteria at all significant checkpoints) at the moment when the PF (co-pilot) become spatially disoriented and began giving improper control inputs.

This disorientation of the PF was the triggering event, which caused him to call the go-around [prior to stabilized approach criteria being violated], the approach to be terminated, and required the PM (the captain) to make corrective [and conflicting] control inputs. These conflicting inputs were not accompanied by the normal exchange of controls communications.

You are correct that the missed approach procedure was initiated before the controls conflict between humans began (but after the co-pilot's disorientation made him suspect a flight controls problem). I was wrong on that point.