Originally Posted by
yoko1
Could also be the result of attempt at using the manual trim wheel, as it was a relatively small movement. It is also possible that it was an anomaly in the data.
DFDR/CVR data won't have an error in a variable like trim position that suddenly happens at that time. A loss of data, that happens, but the engineering values are fixed, so any sensed variable will give an outcome with a constant ac and dc correction/slope and bias. Occasionally the engineering value conversions are incorrect, and the data outcome would be incorrect for all outputs of that variable, that is not the case here. The conversions are post process values... The crew holding very high back pressure against a trim are unlikely to have manually trimmed further forward against their control input, that is not a credible event, so we are left with the possibility that the force on the stab is sufficient to cause creep, and given the design, and IMHO, that should give concern to anyone designing or certifying the plane of that type.