What happened
On 25 October 2022, a Cessable 208B Grand Caravan, registration PK-RVA, was performing an unscheduled cargo flight from Timika to Ilaga, Papua. The aircraft, operated by PT Reven Global Airtranspor, was carrying six motorcycles and various groceries.
Upon approaching Runway 25 at Ilaga, the pilot noted a 3-knot tailwind and an airspeed of 83 knots. As the aircraft touched down, the landing roll was interrupted by a series of three bounces. During these oscillations, the aircraft experienced significant vertical speed changes and fluctuations in engine torque. Realizing the aircraft would not stop within the available runway, the pilot shut down the engine by cutting the fuel lever. The aircraft eventually came to a halt approximately 77 meters beyond the end of the runway. While the two crew members evacuated safely without injury, the aircraft sustained substantial damage, including a detached nose wheel, bent propeller blades, and damage to the left main landing gear and right wingtip.
The investigation
The investigation focused on the operational and maintenance factors surrounding the landing. Analysis of the Garmin flight data logger confirmed that the aircraft experienced excessive normal acceleration during the initial touchdown, which triggered the subsequent bounces.
Regarding maintenance, investigators examined the brake system following reports of a "spongy" brake pedal. The investigation revealed that the average thickness of the brake disc was below the minimum allowable limit. Furthermore, the inquiry found that maintenance practices for the brake system had deviated from the approved Aircraft Maintenance Manual (AMM). Specifically, the investigation noted that the procedures for replacing brake linings and performing the necessary "burn-in" process were not strictly adhered to, which may have allowed air to remain in the system.
Findings
- The primary cause of the overrun was excessive normal acceleration during touchdown, which led to the aircraft bouncing multiple times.
- These bounces resulted in insufficient remaining runway distance to bring the aircraft to a stop.
- Maintenance deviations regarding the brake system contributed to improper system rectification and potential brake instability.
- The operator's training modules lacked specific instruction on bounce-recovery techniques.
Safety action
Following the accident, the Directorate General of Civil Aviation (DGCA) issued a safety circular emphasizing compliance with maintenance regulations for the Cessna 208 series. The operator, PT Reven Global Airtranspor, implemented several quality notices, including mandatory procedures for brake lining replacement, stricter requirements for the brake burn-in process, and improved communication between maintenance and operational departments.