Originally Posted by
ignorantAndroid
Obviously there's no way for a controller to know whether a pilot truly has the correct aircraft in sight.
Absolutely, but he does have the benefit of his own experience and common sense. Yes I accept that his experience may well have deviated to the ‘new normal’ at DCA over time, but common sense would still cast serious doubt on a report of visual on traffic that’s seven miles away at night, even using NVGs. The evidence suggests the LC did subsequently have his doubts, because he asked PAT again if he had the CRJ visual, since he wasn’t manoeuvring to maintain separation. Really a proactive revised clearance would have been more appropriate.