Some things that stand out to me from the report...
Pg 22:
...High workload leads to a reduction in the number of information sources an individual will search, and the frequency or amount of time these sources are checked (Staal 2004). It can result in an individual’s performance on some tasks degrading, tasks being performed with simpler or less comprehensive strategies, or tasks being shed completely...
Pg 27:
...During the IFER, some ATC transmissions combined multiple requests for information and/or actions and UXG’s pilot generally responded to only one of the items...
page 34: (my bold)
...the aircraft’s radio was located low and forward of the control column, the pilot would have needed to reach forward and down, and possibly to one side, in order to see and manipulate the equipment. If in cloud and reliant on the aircraft’s primary flight instruments to maintain aircraft control, any head movement, inadvertent control movement, or diversion of attention away from those instruments would have interrupted the pilot’s instrument scan and affected his ability to maintain the aircraft’s attitude.
The pilot acknowledged a request to change radio frequencies shortly before the accident. However, the ATSB was unable to determine whether attempting to change radio frequencies contributed to spatial disorientation or some other problem (such as task shedding), which in turn led to the pilot being unable to complete the action. Alternatively, any subsequent transmissions from the aircraft may have been blocked by terrain, or the pilot may have tuned to a frequency that was not monitored, or he may not have actually made any transmissions...
http://atsb.gov.au/media/4478740/ao-2012-130_final.pdf
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