Washington plane crash: What we know so far

American Airlines flight 5342 was preparing to land on runway 33 at the Ronald Reagan Washington National Airport last night when it collided with a military helicopter. There were no survivors - how could such a tragedy happen?     On this episode, Niall Paterson is joined by former Royal Air Force Air Vice-Marshal Sean Bell to look at what might have led to the mid-air collision.     Niall also speaks to Dr Michael McCormick, a US air traffic control expert who has developed policies for commercial aircraft to operate in the same airspace as the military.  Producers: Soila Apparicio, Natalie Ktena Editor: Wendy Parker