What happened
After the twelfth parachute jump of the day was completed following sunset, observers on the ground witnessed the aircraft descending into the ocean. The plane was noted to be in a nose-down position with its left wing low. Witnesses reported that the descent did not involve any audible engine malfunctions, such as sputtering or popping, and the aircraft did not exhibit erratic movements prior to the impact.
During the flight in question, which took place at an altitude of 20,000 feet, a skydiver reported experiencing nausea and difficulty breathing. The crew also observed that the pilot struggled to maintain a consistent flight path and failed to respond effectively to small course adjustments. While previous jumps that day had been performed at 18,000 feet, this final mission involved higher altitudes.
Findings
Investigations revealed that no supplemental oxygen was present on the aircraft during the recovery or inspection processes. Furthermore, the skydivers did not observe the pilot utilizing any oxygen systems during the flight. The manufacturer of the aircraft type indicated that the cockpit door was not properly sealed, which would have prevented the pressurization system from functioning correctly.
Analysis of the airframe, engines, and propellers showed no evidence of pre-existing damage or anomalies. The investigation focused on the physiological effects of oxygen deprivation, noting that the lack of a pressurized environment at high altitudes could lead to impaired judgment and delayed reactions. The absence of supplemental oxygen was a critical factor in the flight environment.