Thanks for the replies everyone.
Skiesfull, now we're getting to the crux of the original question
Firstly, I realise the example I've given at EGLL with no radar is a little unrealisitic, but there is at least one port we operate from with no radar, and a few others where ATC is a little ..cough.. unreliable
and I would be very hesitant asking for vectors for the ILS with Wx at minima.
The idea of descending to circling minima, with the radar out and Wx at minima, is to then remain within the circling area (5.28nm), thereby maintaining obstacle clearance, and circle for a short final (2-3nm) and couple up to the ILS.
The second option is to maintain MSA and carry out the full ILS procedure.
FWIW, the TSB of Canada conducted a study into inflight fire/smoke events and found that the
average time from first detection of a fire until the aircraft landed/ditched/crashed was 17 mins.
I had a bit of a play around with both the above options on MSFS (sad, but this has been bugging me) and the first option (2-3nm final) takes about 7-8 mins to get back on the ground. The second option (full ILS) takes about 14-15 mins, which when you compare to the average 17 mins quoted above, could be pushing your luck.
Obviously the first option is the best as far as time is concerned. However, what I am unsure about is if the A/P on the 767 will cope with such a close in intercept of the ILS on 1 engine, or would you be setting yourself up for an unstable approach?
Cheers