What happened
On 26 November 2011, a Cessna 208B Grand Caravan, registration PK-VVG, was conducting an unscheduled cargo flight from Nabire to Bilogai in Papua, Indonesia. The aircraft was transporting a payload of food, cement, and palm oil.
As the aircraft approached the Bilogai airstrip, the crew observed a local villager walking near the edge of runway 27. To avoid a collision, the pilots initiated a go-around maneuver. During this climb, the aircraft's nose pitched up significantly. While attempting to maneuver the aircraft to avoid the surrounding terrain, the aircraft entered a right bank and subsequently lost altitude. The aircraft crashed into a corn field, resulting in one fatality and one serious injury.
The investigation
The investigation conducted by the NTSC established that the aircraft was airworthy and the crew held valid licenses and medical certificates. The investigation focused on the aerodrome environment and the flight dynamics during the aborted landing.
Investigators found that the Bilogai airstrip lacked perimeter fencing and had no warning signals or sirens to alert local residents of approaching aircraft. Furthermore, the terrain in the valley south of the runway was noted to be too narrow to safely accommodate a successful go-around maneuver for this aircraft type. The investigation also noted that communication for Susi Air flights at this location was handled through a ground agent rather than direct air traffic control.
Findings
- The primary cause of the accident was an aerodynamic stall occurring during the go-around maneuver.
- The stall was triggered by an excessively high angle of attack as the crew attempted to climb and maneuver away from the terrain.
- The necessity of the go-around was caused by an unauthorized person walking on the runway shoulder.
- The lack of airport infrastructure, specifically the absence of fencing or warning systems, allowed for the runway incursion.
- The narrow geography of the local valley limited the available margin for error during an aborted landing.