Is this a redux of the Air Force One photo-op that terrified Manhattan? The U.S. Coast Guard gave Washington D.C. a scare on Friday, the anniversary of September 11, when it conducted a training exercise in the heart of the capital on the Potomac River. President Obama was near the exercise when it occurred, visiting the 9/11 memorial at the Pentagon. As a result of the exercise, departures from Washington National Airport were halted. Earlier reports that shots were fired during the exercise appear to have been incorrect.