Nearly 50 NTSB investigators will be searching the Potomac River for evidence to piece together what led to Wednesday night's deadly midair collision between an American Airlines regional jet and an Army Black Hawk helicopter.

A regional jet carrying 64 people collided with an Army Black Hawk helicopter. Reagan National Airport grounded all flights.

Search efforts continue after an American Airlines plane from Wichita, with 64 people on board, collided with an Army helicopter near Washington, D.C., and crashed into the Potomac River.

As recovery operations continue after the midair collision between an American Airlines flight and an Army helicopter, NTSB investigators say they have recovered the two black boxes from the plane and have searched "all accessible areas" of the Potomac River.

No survivors found in crash between Black Hawk helicopter and American Airlines jet over Potomac River near DC

Government agencies are working to understand the cause of a deadly crash between a passenfer plane and military helicopter in Washington D-C last night.The Nat

Several figure skaters, along with their coaches and families, were traveling on an American Airlines plane that crashed into an Army helicopter near Ronald Reagan National Airport in Washington D.C. on Wednesday evening. The plane ended up crashing into the Potomac River.

In the United States, an Airlines regional passenger jet and a Army Black Hawk helicopter crashed into the Potomac River after a midair collision near Reagan Washington National Airport. According to the Washington Post multiple bodies had been pulled from the water. No survivors had so far been found.

Video footage of the incident shows the aircraft flying at a low altitude, before an explosion happened at the moment of impact. The National Transportation Safety Board is investigating.

Authorities say there were no survivors after the two aircraft plummeted into the Potomac River in the country's deadliest aviation disaster since 2001.

Here are 10 key things to know about the Black Hawk helicopter involved in the incident, its capabilities, and the mission it was conducting at the time of the crash.