The Mojave is a great aircraft, just a little heavy. There is only one reason why the Mojave would not maintain height on one engine and that is if the operating engine was "sick". The pilot possibly guesstimated that he could reach YSBK on his descent.....he miscalculated, gee he was only 3nm from the threshold. he lost a lot of height in the turn which he couldn't regain.
Fog viz....well its bloody hard to land in fog, those that have had to be there understand where i am coming from. Landing in fog with a sick aircraft against the calculated chance of returning to and reaching base......it was his call. If the poor bugger had made it, there wouldn't be a post on here, but he didn't. A command decision with the cards stacked against you both ways.... is a very difficult one.