Accident Details
On 23 December 2017 at 00:10 UTC (10:10 local), a Britten Norman BN-2A Islander, registered P2-ISM and operated by North Coast Aviation, struck a ridge at approximately 9,500 ft near the Sarawaget Ranges in Morobe Province, Papua New Guinea. The pilot had elected to fly from Derim Airstrip to Nadzap Airport, tracking across the Sarawaget ranges at an altitude not above 10,000 ft. The aircraft flew northwest from Derim for 6.5 nm, then turned southwest toward the Saidor Gap. GPS data showed a shallow descent toward the ridge prior to the last fix. The impact occurred about 150 meters beyond that fix.
Wreckage and Rescue
No ELT distress signal was reported. During the search, what appeared to be the right aileron was found hanging from a tree near the ridge top. The remainder of the wreckage lay about 130 meters along the projected track. The aircraft struck the ground in a steep nose-down, right wing-low attitude, with most wreckage concentrated at the impact point. The aircraft was destroyed. The pilot, the sole occupant, initially survived the impact and made contact with another company pilot at 16:15 on 23 December. The pilot was reported deceased by the rescue team on 27 December at 22:10; the death certificate recorded the time of death as 10:40 local on 24 December. Rescuers felled trees near the wreckage to construct a helipad.
Probable Cause
The official findings state that cloud buildup along the pilot’s chosen route may have forced him to maneuver closer to the ridge to avoid flying into cloud. The aircraft’s right wing struck a tree protruding from the forest canopy during controlled flight into terrain. It is likely that the right aileron mass balance became snagged on the tree, rapidly dislodging the aileron. The loss of roll control and aerodynamic differential forced the aircraft to descend steeply through the forest and impact terrain.