Originally Posted by
Tractor Boy
You are making 2 huge assumptions:
1. that the 789s will have 30J
2. that the fuel hog 77Ls will keep 42J after PE is added
.
fuel hog?? the drama.

What insight.
Label a frame a fuel hog that, currently, there is no replacement in service and it's a frame that closed down a competing aircraft in the last 5 years.
Is PE on the 77L confirmed? Or is that a huge assumption?