Good on the pilot for admitting his error,at the end of the day what can they do about it,just sack him. He wouldn't be the first that has been sacked from there.
What CASA and the ATSB need to do is look at how the pilots error in judgement come about,to assist the company/industry in preventing accidents like this in the future.
Pritty tough work flying a loaded Chieftain in crappy wx and having to do a circling approach when the wind is blowing 50 knots.
I wish the pilot all the best for the future,he has proven he isn't dishonest.