The FAA is investigating an incident at Ronald Reagan Washington National Airport (DCA) on Tuesday afternoon, after the presidential helicopter Marine One and a departing regional jet appeared to have lost separation. Roughly one minute after Marine One took off, Envoy Air flight 3742 from Reagan National to Pensacola International Airport (PNS) departed, despite rules in place preventing commercial planes from operating while Marine One is active in the area. Sources told Reuters that the two aircraft appear to have breached separation rules, which require aircraft operating near an airport to remain at least 1.5 miles apart horizontally and 500 feet apart vertically. This includes closing the Washington Helicopter Route Four between Hains Point and the Wilson Bridge and barring controllers from using visual separation to handle helicopter traffic. ATC staffing has been a major issue at DCA, with the latest FAA figures revealing close to a third of controller positions are still unfilled.