This is Ask An Expert, where every weekday at 9:20am on KCBS, we're giving you direct access to top experts in various fields. All eyes have been on Washington DC following the deadly plane crash that killed more than 60 people and involved a military helicopter. And the question atop everyone's mind: how did this happen? For some insight, KCBS Radio anchors Margie Shafer and Eric Thomas spoke with Keith Cianfrani, owner of Aviation Safety consultants. He's a retired US Army Lieutenant Colonel, and has experience as an aviation safety officer, helicopter pilot and accident investigator for the US Army safety center.