This thread is a bit like watching a train wreck. Its horrible, but I can't look away.
I'm guessing that guys who fly twins have a "there but for the grace of god..." shudder going down their spines. I think we want to know what happened because we're all secretly wondering if we could have done any better.
It seems to me that the guys who fly singles just don't quite understand what it would be like and we're seeing all the old wives tales about twins being trotted out. I think that flying a twin with an engine shut down can never be understood until you've done it. No amount of reading or hangar flying will help.
Its worth the reminder that the Whyalla accident had the pilot crucified for piloting error for some time before the truth about mechanical problems came out.
I'm prepared to assume as a starting point that the pilot was competent and intelligent. He had an issue at good altitude that should have been straightforward to deal with. At that height, I suspect I would have elected to go to home base where you know the area well and there are friendly LAME's etc. He would have known all the landmarks so navigating would have been one less thing to think about. As has been pointed out, climb performance on a single engine is irrelevant because what he really needed was a moderate descent rate. He probably only needed 55% - 65% power on the remaining engine to make Bankstown.
For the Mayday pedants, in my view, the main reason the call is required is to get the attention of ATC. In this case he clearly already had ATC's full attention. There has been extensive discussion of this subject on another pprune thread regarding the recent JFK emergency incident. In many countries (notably the US) there is no requirement to make a formal mayday call to declare an emergency. In this incident, the point at which the line was crossed to declare an emergency, it seems to me that ATC were already handling it as such, so it was essentially redundant. The radio call that would have changed the outcome of this flight does not exist.
It looks like something else has transpired after the pilot shut down an engine to turn this from a difficult situation to a full blown emergency. I'm guessing that by the time this manifested itself and the poor guy processed the new information that he had rapidly diminishing options.
Something very unusual has happened to cause loss of power to both engines. Too much air in the tanks or fueling with JetA1 are the common reasons that we jump to. Both will be quickly determined by the ATSB. JetA1 has an sg of about 0.8 and Avgas about .72, so its heavier. But Avgas & JetA do dissolve quickly, except on the other hand fuel does not mix well in tanks. It tends to stratify. In-ground tanks (eg service stations) do not mix different fuel octane ratings well for example. How well it mixes will be determined by the tank plumbing. If its like other Pipers with hoses interlinking tanks, it might take a while to mix enough to upset the engines. Spark ignition engines will tolerate a level of Jet A / Diesel / Kero. The old side valve low compression car engines (ie Ford Prefect) would run on kero happily once they were hot. Its all too complex to speculate.
At the end of the day, I know I would have done better - except when I'm alone when I worry if I would have done as well.
I've had an engine failure on takeoff in a single and a rough running engine in a single at altitude at night returning to Melbourne. I now mainly fly twins and I'm not prepared to judge the pilot. I really want the ATSB to do a good job of investigating this accident quickly so I can see if there are lessons. In the meantime I just hope I don't suffer the same circumstances.