History of the Flight
On 5 December 2019, a Cessna C208B aircraft registered PK-BVN was operated by PT. ASI Pudjiastuti Aviation (Susi Air) on a scheduled passenger flight. The flight originated from John Becker Airport (WATQ), Kisar, with a planned route to El Tari International Airport (WATT), Kupang. The aircraft had two pilots and twelve passengers on board. The flight was conducted during daylight in visual meteorological conditions.
Prior to departure from Kisar, the second in command (SIC) performed a preflight check and noted that no aircraft system malfunctions were recorded or reported. The SIC was aware that supplemental oxygen was not available in the aircraft; however, it was not required for unpressurized aircraft operating at or below 10,000 feet.
Crew and Aircraft
The pilot in command (PIC) and SIC were both on duty. The aircraft, a Cessna C208B, was in serviceable condition. The PIC acted as pilot monitoring, while the SIC was pilot flying during the sector from Kisar.
The Incident
Approximately 15 minutes after departure at 0359 UTC, the aircraft reached a cruising altitude of 10,000 feet. During the cruise, the crew discussed a health-related topic. Subsequently, the SIC began to feel anxious and experienced shortness of breath. His condition worsened when he recalled the absence of supplemental oxygen in the aircraft, leading to more rapid breathing.
The PIC became aware of the SIC's distress and requested air traffic control (ATC) to allow a descent. ATC instructed the pilots to stand by. The SIC then felt dizzy, experienced tunnel vision, and subsequently a blackout. According to the PIC, the SIC lost consciousness for approximately 20 seconds. The PIC declared a MAYDAY and requested diversion to Presidente Nicolau Lobato International Airport (WPDL) in Dili, Timor Leste. This decision was based on the shorter distance to Dili compared to continuing to Kupang.
The PIC informed ATC that the SIC had experienced a heart attack and requested an ambulance to be on standby. ATC acknowledged and approved the request. The PIC initiated a descent toward Dili. The SIC regained consciousness, drank water, and, upon realizing the aircraft was descending, was able to take deep breaths, which improved his condition.
Landing and Aftermath
The aircraft landed at Dili at 0457 UTC. The SIC was taken by road to a nearby hospital for medical treatment. There were no injuries to any person and no damage to the aircraft.
Investigation
The Komite Nasional Keselamatan Transportasi (KNKT) led the investigation, with participation from the South Africa Civil Aviation Authority and the Timor-Leste Gabinete Prevensaun e Investigasacao Insidente e Acidente com Aeronave (GPIAIA). At the time of issuing the final report, KNKT had not received notification of safety actions taken by Susi Air. The KNKT issued safety recommendations to Susi Air as a result of this occurrence.