Controlled Flight Into Or Toward Terrain, PT. Spirit Avia Sentosa (Cessna 208B Ex Pk-Fso); Oksibil Area, Papua, KNKT.17.04.11.04

On 12 April 2017, a Cessna C208 aircraft registered PK-FSO was being operated by PT. Spirit Avia Sentosa (FlyingSAS) for unscheduled cargo flight from Tanah Merah to Oksibil.

At 1144 LT on daylight condition, the aircraft departed Tanah Merah with intended cruising altitude of 7,000 feet. Prior to departure, there was no report or record of aircraft system malfunction. On board the aircraft was one pilot, 1,225 kg of general cargo and 800 pounds of fuel which was sufficient for about 3 hours of flight time.

At about 29 Nm from Oksibil, the PK-FSO aircraft passed a Cessna 208B aircraft which was flying on opposite direction from Oksibil to Tanah Merah at altitude 6,000 feet. The Cessna 208B pilot advised to the pilot on radio frequency 122.7 MHz that the PK-FSO aircraft was in sight. The pilot responded that the aircraft was maintaining 7,000 feet on direct route to Oksibil.

At 1240 LT, the Oksibil tower controller received another phone call from the FlyingSAS officer at Jakarta which informed that the FlyingSAS flight following system received SOS signal (emergency signal)from PK-FSO aircraft which located approximately 6 Nm north of Oksibil. Afterwards, the Oksibil air traffic controller advised the occurrence to the Search and Rescue Agency.

On 13 April 2017, at 2211 UTC, the PK-FSO aircraft was found on ridge of Anem Mountain which located about 7 Nm north of Oksibil. The aircraft was destroyed by impact forces and the pilot was fatally injured.

The investigation determined that the aircraft serviceability was not issue in this occurrence. Therefore, the analysis discussed the aircraft flight profile; pilot medical condition and activities; organization oversight; and pilot medical examination. The investigation concluded the contributing factor of the accident was the possibility of the pilot being fatigue, physical and environment condition increased pilot sleepiness which might have made the pilot inadvertently falling asleep indicated by no pilot activity. The absence of GA-EGPWS aural alert and warning was unable to wake up the pilot.

The KNKT has been informed safety actions taken by the FlyingSAS and Balai Kesehatan Penerbangan (Aviation Medical Center) resulting from this occurrence, however, there still remain safety issues that need to be considered. Therefore, the KNKT issues safety recommendations addressed to the FlyingSAS, Aviation Medical Center and Directorate General of Civil Aviation.