Pilot error, lack of proficiency and operational issues were factors in the deadly collision of two Marine Corps CH-53 helicopters in January, a media investigation revealed. The helicopters, from a squadron of Marine Aircraft Group 24, 1st Marine Aircraft Wing in Hawaii, crashed in the ocean during a late-night training mission on Jan. 14, killing 12.
Source: avwebReport: Pilot Error, Training Cited In Marine Heli Crash