A Marine helicopter that slammed into a snowy mountain peak in Southern California last year, killing all five service members on board, was not equipped with a device that preserves flight data ...

Adina Azarian, 49, Aria Azarian, 2, Evadnie Smith, 56, and Jeff Hefner, 69, died in the crash on June 4 ... due to a lack of oxygen during the flight and became incapacitated, the NTSB wrote ...