Originally Posted by l2flare

I'm not 100% on the international 117 stuff, so correct me if wrong, but I'm pretty sure that pairing is illegal.

With only 25:20 rest in LHR you still calculate table limitations off BOS time. Meaning you would have to run an augmented crew (for just the return leg), report later than 5am East coast time, or allow for 36 hours of rest in LHR.