The victims include top figure skaters from the US and Russia, a young pilot, flight attendants, and a lawyer travelling home on her birthday. Here are some of the people believed to have been on board the helicopter and the plane.

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 BBC's Analysis Editor Ros Atkins on the unanswered questions around a fatal crash between a commercial airplane and a military helicopter near Washington DC.