Shutting down 1 pack on a 2 Pack aircraft to save fuel....
Ok on 767 A330 etc when you are in cruise with 2 packs operating. The pack out put is aroung 60%. Built in fuel saving by manufacturer.
If you lose a Pack the servicable Pack 767 defaults to 146% flow and the A330 goes to High flow (not sure of the figure but is similar). regardles of "high flow" switch position
So staright away your bleed loads are higher ... therefore higher fuel burn with 1 Pack running.
It will take a clever aerodynamicist to tell us whether the reduced drag due to 1 Packs cooling doors closed will compensate for the added fuel burn due to higher bleed loads.
