At the moment there is an odd dynamic in the 756 and 76T fleet in IAD. L-CAL types have some loathing, fear, disdain, or something else that prevents them from bidding L-UAL metal and a large number of IAD 76T folks were actually JFK transplants that have since returned to EWR 756. Prior history was JFK junior and IAD senior. IAD had a 73 base before United parked their 73s to make way for the merger and those 73 captain's mostly went to 777 IAD FO so I suspect there will be a fair amount of senior 777 FOs that will take the IAD 73 positions. I just have to laugh when I see CAL types not willing to take A320 Captain bids or 76T FO bids. They could dramatically improve their trips and/or pay but the anti-UAL bias is so high in the junior CAL ranks that they can't bring themselves to take the bid. No worries for me 'cuz it's making the EWR A320 Cap bids way more junior than the 73 EWR Cap bids and that's ok by me