For the ‘split thrust lever’ or ‘asymmetric power’ views, see the HF section of the PSM+ICR report, which considers events from the Boeing Engine Malfunction database.
There are 7 throttle and 8 instrument related events in the category ‘Failure to monitor throttle position and engine parameter display.’
These might moderate some of the extreme hindsight biased expectations of human perception. People are not very good monitors, do not observe what we see as obvious after the event, are distracted, suffer fixed mindset, over-focus or react to apparently irrelevant aspects, … etc,
Selected texts;
- #1 eng. throttle retarding toward idle while #2 throttle remains at high thrust level.
- #2 eng. throttle jammed at 94% while #1 eng throttle slowly reducing power under A/T command.
- Failed to notice #2 eng throttle position when diagnosing problem in #1 eng.
- #2 eng. throttle stuck at idle during level off while #1 throttle advanced with A/T engaged; A/P holding left aileron; airplane began to bank right
- #1 eng. went sub-idle during level off at cruise and was not detected for over seven minutes; throttle split, airspeed bleed off, finally 15 degree bank when A/P could not compensate for asymmetric thrust.
- Crew failed to note that #4 eng. had gone sub idle while engines controlled by A/T.
- None of the three pilots on flight deck noticed that #2 throttle had inadvertently been displaced below full power.