A preliminary analysis of the flight data and voice recorder on board a Black Hawk helicopter leading up to the collision with a commercial flight over Washington, DC, on January 29, indicated the helicopter’s altimeter may have been inaccurate and the pilots may not have heard some calls from the Reagan National Airport control tower,

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.

The National Transportation Safety Board says altimeter in the Black Hawk helicopter may have malfunctioned before the DCA mid-air collision with an American Airlines jet. All 67 people aboard died.

The Army on Friday released the names of two male aviators who were killed when their Black Hawk helicopter collided with an American Airlines regional jet on Wednesday night. But in an extraordinary step, the Army did not identify the third crew member, a female pilot, citing her family’s request for privacy.