Voice recordings from the Black Hawk helicopter involved in the crash with a commuter plan in Washington, DC, on January 29 have been released by the NTSB in a briefing for reporters Friday.

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.

Accident investigators are seeking to determine the accuracy of cockpit altimeter readings presented to pilots of the Sikorsky UH-60 Black Hawk that collided with a MHIRJ CRJ700 regional jet near Ronald Reagan Washington National airport on 29 January.