Originally Posted by
FullWings
That would apply if you were in the cruise and experienced a trim malfunction. In this case it was an aircraft getting airborne and having the symptoms of UAS. Would you expect the aircraft to be in trim when you’re unsure what speed you’re doing or whether you are speeding up or slowing down? No.
Also, the trim switches were probably working but the system would likely trim back the other way a bit later. Very insidious and difficult to deal with shortly after takeoff, especially as the operation of MCAS was unknown to the pilots...
Your description doesn't make sense. The crew radio'd a return to base early in the flight. Assumption is they disengaged autopilot at that point, or it abdicated. They then had the aircraft under some sort of control (basically level at 5000 feet) for six minutes. That's a long time. If they were counteracting insidious MCAS trim for those six minutes then they knew they had a stabiliser runaway. Did they complete the checklist ? If so, was it ineffective ? Or did some other failure overwhelm the aircraft ? All unanswered...