It is likely the Black Hawk pilots “stepped on” the communication for less than a second by pressing the microphone key to communicate back to the control tower, she said.

National Transportation Safety Board officials said Friday that a key transmission from Reagan National Airport’s air traffic control tower may not have been heard by Army Black Hawk helicopter pilots just before they were collided with an American Airlines regional jet last month,

The Black Hawk that collided with an American Airlines jet in January may not have had accurate altitude readings, investigators said.