OK465, whilst the discussion is about airspeed, the ASAGA study, and inference in this accident, suggests that it is the combination of factors which challenge pilot’s mental resources. In the extreme, and for a short period, the overall situation / task appeared to be beyond human capability. I doubt that any simulator experiment would accurately determine the combined effects; neither would a comparison with a dial equipped fight deck. In addition, the study involved more conventional approaches and automation which worked as imagined, … up to the point of GA.
All that might be deduced about the speed display in this accident is that it is possible that the tape display contributed higher mental workload than might have a dial instrument, based on background research, but what the effect was in comparison to the mental effort in understanding the state of automation or aircraft flightpath cannot, and should not be judged.
Other aspects with potential for greater influence could arise from management policies. It is reported that the operators automation policy was to maximise the use of automation, which could be interpreted in three ways: AP+AT, Man pilot+AT, and Man thrust+AP, but there was no specific clarification or advice. Yet the excluded combination Man pilot+Man thrust, if used could have had significant influence on the approach and crew performance.
Also, aspects of the report could be interpreted as the training policy / economics only allowing (allocating) one attempt at each training scenario, thus both the trainee and instructor may have expected to succeed at all times. If this view influenced the crew then there could have been greater pressure on the trainee to resolve the situation, and for the inexperienced instructor not to fail a candidate (a form of press-on-itis). Whereas the situation (from hindsight) actually required early intervention, which without judging pass/fail or allocating blame, was an ideal learning opportunity (experience) from the debrief.
As with airspeed, the contribution of policy cannot be judged, but these should be considered under ‘what if’, inviting individuals and organisations to look at the details or interpretations of their policies and procedures.