poorjohn
even after two fires and an OAG (sic) fleet the best way forward is still to leave everything as unchanged as possible, and put a steel box around it.
I think there's a lot more involved in the proposed modification than just putting a box around it. There is talk of cell re-design and battery modification to isolate cells thermally.
Walnut
so with a double engine failure it is essential to start the APU, (from the battery)? I appreciate the windmilling engines should provide some output of both electrical & hydraulics but again the pilot is faced with pressurisation problems
The 787 starts the APU automatically in the case of a double engine failure, yes from the battery, but it would be assisted by windmilling engines and the RAT.
The pressurisation problems are no worse than any other twin when faced with a double engine failure. You're going down anyway, so the most important action for loss of pressurisation is already initiated!