The failure of maintenance personnel to properly maintain the cargo door latch, resulting in an in-flight opening and separation of the cargo door, and substantial damage to the horizontal stabilator when it was struck by remnants of the cargo door.

the pilot's continued VFR flight into instrument meteorological conditions and his failure to maintain adequate altitude/clearance from terrain. Low ceilings and snow covered terrain were factors in the accident.

THE PILOTS VFR FLIGHT INTO IMC CONDITIONS, AND HIS FAILURE TO MAINTAIN SUFFICIENT ALTITUDE WHILE MANEUVERING. CONTRIBUTING TO THE ACCIDENT WERE THE WHITEOUT SNOW AND FOG CONDITIONS.