The presumtion of being able to operate a Classic B747 without a Flight Engineer or someone at the panel is that nothing needs to be changed during the flight. There is a very big diffence between setting up an unpressurised aircraft, set tank to engine for a quick circuit and a 12 hour sector say PER/JNB. My 18,000 hours as a B707/747 FE kept me busy constantly adjusting cabin temps, pressurisation and ballancing fuel. Some 747 models have 9f uel tanks which have to be used in a set order. Over a 12 hour sector the fuel use on each engine varies tremendously and rebalancing is a must.
The other presumption is that no abnormal precedures have to be carried out.
For most abnormals that would be difficult co ordinating switching from the pilots seat.On a long sector I found that there was often an abnormal checklist to run. The operator that I spent most of my time with also designated the FE as the checklist handler. While I am in no way saying the pilots couldnt handle a checklist, the crew training had the FE do it. In time of problems we do things as we are trained so no FE means pilots doing what they have not practised and on the B747 multiple checklists are common when a primary system fails.
I agree with earlier comments. The only 2 man situation that works for all circumstances is Capt/FE. I've done it a few times and it works because both can check each other. It's impossible for the F/O to check the FE as the panel can't be seen from the F/Os seat.
As far as the Ansett B767 FEs are concerned, I'ver said on PPRUNE before that I have seen an original B767 sales book which promoted the aircraft as a 3 crew aircraft. Ansett was a launch customer and bought the aircraft as advertised. It then made an agreement with the AAFEA on crewing the aircraft that it purchased. The aircraft then changed but Ansett stuck to its agreement. For the first year at least it was a good decision because of the many problems that they had and the MEL relief that was given by carrying the FE. After that the situation was more equestionable. I can also remember seeing B767 FEs at NRT for an Asian airline??? in the very early days of B767 ops.
For the record I am not ex Ansett and never flew as a B767 FE.
Wunwing