This is a whole-of-government effort." The flight data recorders, often called "black boxes," have not been recovered yet, Homendy said.Start the day smarter. Get all the news you need in your inbox each morning.

Investigators from the Federal Aviation Administration will join the NTSB-led investigation of Wednesday night’s midair collision between an American Airlines passenger jet and a military helicopter near Reagan Washington National Airport.

All are feared dead in a crash involving a Black Hawk helicopter built by Connecticut's Sikorsky and an American Airlines plane in Washington, D.C.