A passenger jet and a Black Hawk helicopter collided in midair Wednesday and crashed into the Potomac River near Reagan National Airport near Washington, D.C., officials said. The plane, a PSA Airlines Bombardier CRJ700 regional jet, was carrying 60 passengers and four crew members, CBS News learned. There were three soldiers aboard the Sikorsky H-60, a Defense Department official told CBS News. At least 18 bodies were recovered Wednesday night as the search for survivors continued. Here’s what we know so far about the crash. What happened? A PSA Airlines plane, operated by American Airlines, collided midair with a…..