WPR17FA170 · Beech 19A

The private pilot and three passengers departed on a local flight in day visual meteorological conditions. Radar data identified the flight shortly after takeoff at 1,800 ft mean sea level (msl), traveling on a northwesterly heading. As the flight continued, the altitude varied between about 1,100 ft and 1,800 ft as the airplane conducted three 360° turns. Following the third turn, the airplane was heading west, climbing from 1,800 ft to 2,000 ft msl as it approached a ridgeline that ran perpendicular to its flight path. Data indicated that the airplane then entered a left turn; the data ended in the vicinity of the accident site at an altitude about 1,900 ft msl.

The wreckage was located on steep, mountainous terrain at an elevation about 1,900 ft msl. The airplane collided with the densely-vegetated terrain in a nearly wings-level attitude about 50 ft below a ridge that ran perpendicular to the main north/south running ridgeline. The highest point of the ridge line near the accident site was about 2,800 ft. The accident site was located south of a pass in an area commonly used by pilots to transition the inland mountains of the island. The lowest point of the pass was about 2,100 ft.

Postaccident examination of the wreckage did not reveal evidence of any mechanical failures or malfunctions that would have precluded normal operation, and a witness reported that the engine was producing power until impact.

It is unknown if the pilot was attempting to cross the ridge through the pass, was planning to fly along the ridgeline when the impact occurred, or was going to attempt to climb over the higher ridge. Regardless, the pilot decided to fly at low altitude, providing him little margin for error and he failed to maintain sufficient altitude above the mountainous terrain.

Verbatim NTSB analysis and probable cause from the NTSB dataset