The National Transportation Safety Board (NTSB) urged the public not to “speculate” about the cause of the deadly midair collision near Ronald Reagan Washington National Airport in a Thursday

National Transportation Safety Board Chairwoman Jennifer Hommendy described the investigation into the crash Wednesday night as an “all-hands-on-deck event” for the agency during a news conference Thursday in which she appeared with members of the board and a senior investigator overseeing the probe.

Divers return to the Potomac River as part of the recovery after the United States’ deadliest aviation disaster in almost a quarter century

The National Transportation Safety Board is an independent federal agency tasked with examining serious transport-related accidents.

Fatal crashes like the one that happened near Washington on Wednesday are increasingly rare because of modern aviation safety procedures.

Fatal crashes of commercial aircraft in the U.S. have become a rarity. The deadliest recent crash was in 2009 near Buffalo, New York. All 45 passengers and the four crew members were killed when the Bombardier DHC-8 propeller plane crashed into a house. One person on the ground also was killed.

An American Airlines jet with 60 passengers and four crew members aboard collided Wednesday with an Army helicopter while landing at Ronald Reagan National Airport near Washington, prompting a

Continental Airlines Flight 3407 crashed into a house in Clarence Center, killing everyone on board the plane.

Air crash investigations can take months, and federal investigators told reporters they would not speculate on the cause.

Air crash investigations can take months, and federal investigators told reporters they would not speculate on the cause.

May 11, 1996: A Valujet Airlines flight crashed into the Everglades about 10 minutes after takeoff from the Miami International Airport. The crash killed all 105 passengers and five crew members. Oct. 31, 1994: An American Eagle flight in Roselawn, Indiana, crashed, killing 64 passengers and four crew members.

Authorities have switched to a recovery mission in the Potomac River following a midair collision between an American Eagle flight and an Army Black Hawk helicopter near Reagan National Airport in Washington,