I remember going into DCA in the evening push last year when they were having all the flooding problems and the tower equipment was going in and out of service. Potomac was telling all of us not to be surprised if we couldn't get radio contact with tower as it had been a problem all day and if needed look for a light gun signal. True not identical as that would be an old school clearance but, not the first time DCA has had tower issues. Also, if you read the story you'll see that the first plane DID go around when they couldn't get an answer and recontacted Potomac for help.