Why oh why would you try and stay under control steps when you are having engine problems?????????
6:1 profile in a PA31 will give you a TOD of 42NM at 7000 feet. I'd assume he had both the engines at a decent power setting, maybe one feathered and was aiming for the 1000 feet target. I heard him on LIVE ATC requesting immediate return to Bankstown and descent to 1000 feet. When he powered up perhaps she just kept going when the new problems presented themselves. He couldn't have been more than 20 mile out when he turned back so he would have needed 1000 feet a minute or so to get back in to Bankstown.