Clearly the next few months are going to be critical, a refusal from the DoT will have a massive impact on LGW, not only will 10's of thousands of long haul flights need to rebooked/refunded, there are also many connecting flights into/out of LGW that have been pre sold.
If at the end of the summer the LGW/US flights are operating and the 787 starts to settle down with 6 or 7 aircraft operating things might improve on the cost side, but adding 12 pilots a week for the first 3 months is a big up front investment.......