NTSB Investigates Altitude Data and Missed Directive in Deadly D.C. Midair Collision

The crash between an Army Black Hawk helicopter and an American Airlines jet over the Potomac killed 67 people, making it the deadliest U.S. air disaster in 23 years.

Investigators are examining conflicting altitude data from the Black Hawk helicopter, suggesting the pilots may have had inaccurate information during the flight.
The helicopter crew possibly missed a critical air traffic control instruction to pass behind the American Airlines jet seconds before the collision.
The Black Hawk was flying above the 200-foot altitude limit for its route, but it is unclear if the pilots were aware due to discrepancies between altimeter readings.
Night vision goggles worn by the Black Hawk crew may have impaired their visibility during the nighttime training flight.
The Federal Aviation Administration has restricted helicopter and airplane traffic in shared airspace near Reagan National Airport following the crash.