Departure and Weather Conditions
The aircraft departed during a break in the weather after waiting for a special VFR departure. The departure radio call was the last communication from the flight. Weather conditions remained marginal, with icing reported in clouds and freezing drizzle. The flight was transporting a dentist and a technical assistant for clinical work in area villages under the US Health Department. There was no pressing or urgent need to adhere to a schedule if weather dictated a postponement.
Accident Sequence
Aircraft wreckage was located on the side of a mountain at 650 feet above mean sea level. It had collided with rising terrain while in a descending turn. The aircraft broke apart, leaving wreckage scattered over a distance of 493 feet before coming to rest. The pilot and one passenger remained in the wreckage. The right front passenger was ejected and found near the wreckage site.
Post-Accident Observations
Witnesses at the crash site noted ice measuring from 1/8 to 3/4 inches thick on the broken wings and airframe parts during recovery operations.
Probable Cause
Official findings identified two occurrences:
- Occurrence #1: In-flight encounter with weather during cruise phase, with findings of icing conditions, fog, inaccurate weather evaluation by the pilot-in-command, inadequate preflight planning/preparation by the pilot-in-command, and VFR flight into instrument meteorological conditions performed by the pilot-in-command.
- Occurrence #2: In-flight collision with terrain/water during maneuvering phase, with a finding of rising terrain.