What happened
On December 11, 2007, a Fletcher FU2 single-engine aircraft, registration PK-PNB, was engaged in routine aerial fertilization operations at the Cendrawasih Estate in Sentani, Papua. Operated by Sinar Mas Super Air, the aircraft had successfully completed ten consecutive fertilizer drops that morning without incident.
During the eleventh flight, the pilot attempted to adjust the GPS settings to target specific areas of the plantation. Shortly after takeoff, the aircraft performed a steep left turn at an extremely low altitude. During this maneuver, the aircraft drifted outside the plantation boundaries into a forested area. The left wing struck several tall trees, causing the outer wing to break and the main spar to fail. The loss of structural integrity led to a total loss of control, and the aircraft crashed. The pilot sustained fatal injuries, caused by the impact and the forward movement of 1,300 kg of fertilizer that crushed the cockpit area upon impact.
The investigation
The investigation examined the aircraft's structural failure, the operational management of Sinar Mas Super Air, and the regulatory environment in Indonesia at the time. Investigators analyzed wreckage from the left wing, which showed clear evidence of impact with trees. The engine and propeller were also inspected; findings indicated the engine was at high power during the impact.
Beyond the physical wreckage, the inquiry looked into the company's organizational structure. It was established that the aerial manuring operations were overseen by a coordinator lacking aviation expertise. Furthermore, the investigation reviewed the lack of standardized training syllabi, the absence of a dedicated chief pilot, and the lack of formal communication equipment between ground staff and the pilot.
Findings
- The primary cause of the accident was the left wing striking trees during a low-altitude, steep turn outside the designated plantation area.
- The pilot died due to severe trauma from the impact and being crushed by the heavy fertilizer load shifting forward during the crash.
- The operator, Sinar Mas Super Air, lacked an official Agricultural Operating Certificate and did not have formal company manuals for operations or maintenance.
- There was a significant lack of organizational oversight, with flight training being conducted informally by senior pilots without a standardized syllabus.
- Regulatory gaps existed, as the Directorate General of Civil Aviation had not yet implemented specific safety regulations (CASR Part 137) for agricultural aviation, and the distribution of Airworthiness Directives (AD) regarding wing spar fatigue was ineffective.
Safety action
Following the accident, recommendations were made to the Directorate General of Civil Aviation to establish specific regulations for agricultural flights and to improve the monitoring of Airworthiness Directives. Sinar Mas Super Air was advised to appoint aviation-qualified management, implement formal training and maintenance controls, and improve airstrip safety equipment, such as wind speed indicators and communication tools.