Not sure this is a pilot thing but …

DCA-EWR flight this afternoon (4413, dep 4p), delayed inbound means outbound delay.

however, the plane for the next DCA-EWR flight (dep 5:15p) has arrived already.

At least in theory this plane could be turned and reduce the delay of the 4pm flight, and the 5:15 flight could use the late inbound plane, and still depart on time.

all are CRJ-550s.

Any idea why they wouldn’t make this swap? Do the
pilots or crew need some amount of “rest” before turning (i
assume the same pilots just turn around)