What to know about the NTSB, the agency investigating the DC plane crash

▶ Follow the AP’s live coverage of a midair collision between a passenger plane and a military helicopter. WASHINGTON — A collision between an American Airlines passenger jet and an Army helicopter near Washington, D.C., that killed 67 people brought renewed focus on the federal agency charged with investigating aviation disasters. The NTSB is an independent federal agency responsible for investigating all civil aviation accidents as well as serious incidents in the U.S. involving other modes of transportation, such as railroad disasters and major accidents involving motor vehicles, marine vessels, pipelines and even commercial space operators. For the investigation into Wednesday’s crash, the NTSB will establish several different working groups, each responsible for investigating different areas connected to the accident, board member Todd Inman said. Inman said those groups include operations, which will examine flight history and crewmember duties; structures, which will document airframe wreckage and the accident scene; power plants, which will focus on aircraft engines and engine accessories; systems, which will study the electrical, hydraulic and pneumatic components of the two aircraft; air traffic control, which will review flight track surveillance information, including radar, and controller-pilot communications; survival factors, which will analyze the injuries to the crew and passengers and crash and rescue efforts; and a helicopter group.