Arsenal play at Man U on Sunday 28th Feb - Sky TV game - and then scheduled to play again in the PL Weds 2nd March. It's very congested.
If it went to a replay my guess would be that our home game with Brentford on tuesday March 8th could get hooked. ? Arsenal are free that mid-week.
Surely no chance? That would leave just a few days to sort out tickets etc for the quarter final (12th March weekend). It would have to be week commencing 29th February. Probably Wednesday 2nd March as Arsenal play on the Sunday. Birmingham v City and Arsenal v Swansea would have to be rearranged.
It's all about TV rights now. A City v Arsenal replay will surely be on TV (BBC or BT) so it can't clash with any PL game Sky might be showing on 1st or 2nd March or any Champions League game (8th or 9th March)