What happened
On December 31, 2016, a Pilatus Porter PC-6, registration PK-BVM, was conducting an unscheduled cargo flight from Timika to Ilaga Airport in Papua, Indonesia. The aircraft was operated by PT. ASI Pudjiastuti Aviation, carrying 853 kg of cargo with a single pilot on board.
During the approach to runway 25, the pilot communicated with the Ilaga Flight Information Services Officer (FISO), receiving reports of calm winds and ground fog. After completing the landing sequence, the aircraft touched down approximately 100 meters from the start of the runway. Upon touchdown, the pilot noted the aircraft was drifting left of the centerline. An attempt to correct the deviation using right rudder and moderate braking caused the aircraft to yaw sharply to the right. In a subsequent attempt to recover using full left rudder and heavy braking, the aircraft veered off the paved surface. The right wing tip struck an elevated slope at the edge of the runway shoulder, causing the aircraft to rotate 45 degrees and come to a stop 20 meters from the runway pavement. There were no injuries reported, though the aircraft sustained substantial damage, including a broken right wing, a bent tail section, and damaged propeller tips.
The investigation
The investigation examined the flight path, meteorological conditions, and aerodrome data. Investigators noted that the pilot was highly experienced, with over 5,300 total flying hours, though only 99.5 hours were on this specific type. The investigation also reviewed discrepancies in airport documentation, noting that the official Aeronautical Information Publication (AIP) and the operator's airstrip booklet provided conflicting information regarding the elevation and runway slope at Ilaga.
Findings
- The aircraft's right wing struck a shoulder slope that was higher than the runway elevation.
- Conflicting airport elevation and runway slope data existed between the official AIP and the operator's internal documentation.
- There was no dedicated meteorological station at Ilaga; weather data relied solely on observations from the FISO.
- No standard VFR arrival or departure routes were established for the Timika to Ilaga sector in the published AIP.
Safety action
Following a series of similar occurrences in the region, the KNKT proposed several safety recommendations. These included calls for the DGCA to review runway extensions and the installation of visual aids like PAPI to prevent pilot illusions caused by the runway's upward slope. Additionally, recommendations were made to standardize arrival routes and to improve the resolution of terrain databases used by EGPWS in the mountainous Papua region.