page_title: Trigana Air Flight 267
section_title: Investigation
hierarchical_section_title: Trigana Air Flight 267 / Investigation
caption_attribution_description: English: A Trigana Air Service ATR 42 at Labuan Bajo's Komodo Airport, operating as a TransNusa flight. Digital photo of PK-YRN taken at Labuan Bajo Airport, Indonesia and uploaded for use in the Trigana Air Service article.
context_page_description: Trigana Air Flight 267 was a scheduled passenger flight from Sentani to Oksibil in the eastern Indonesian province of Papua. On 16 August 2015, the ATR 42 turboprop operating the service crashed on approach in the Bintang highlands region of Oksibil, killing all 49 passengers and 5 crew members.
  With 54 deaths, it is the deadliest accident involving the ATR 42, and the airline's deadliest accident since its establishment in 1991.
  The Indonesian National Transportation Safety Committee published its final report into the accident in December 2017.
  Deviation from visual approach guidance and visual flight rules without regard to weather and terrain, and the likely deactivation of the EGPWS system contributed directly to the crash, compounded by shortcomings in Trigana Air's safety culture.
context_section_description: The Indonesian National Transportation Safety Committee (NTSC or KNKT) opened an investigation to the crash. In line with international regulations, as the aircraft was built in France, its Bureau d'Enquêtes et d'Analyses pour la Sécurité de l'Aviation Civile (BEA) participated, sending three investigators. Aircraft manufacturer ATR also assisted and sent four technical advisers.
  The flight manifest released by Trigana was found to be wrong, being for another Trigana flight. As a result, the Chairman of Sentani Airport was fired by the Transportation Ministry. Sixteen workers were also investigated by the police because of their involvement. Two of Trigana's staff remained in custody. Ignasius Jonan, Indonesian Minister of Transportation, criticized the airport staff saying the situation was a "big mess" and needed to be cleaned up.
  Investigators rebuilt the predicted flight path of Flight 267, using Google Earth and data from the CVR and its spectrum analysis. They noted that the Flight Data Recorder was unusable. The analysis of the CVR revealed that at 14:55 local time, the flight crew of Flight 267 stated their intention to make a direct left base. Immediately after that, Flight 267 deviated from its predicted flight path.
  Flight 267 deviated to the right. The area on the right side of Flight 267 was surrounded by mountainous terrain. Some of the terrain was as high as 8,000 ft. In addition, Papua's unpredictable weather would endanger the flight easily. Pilots have reported that fogs sometimes "came out of nowhere", which could limit the pilot's visibility. Though good condition was reported in the area, there were also localized fogs in the mountains. According to the NTSC, based on the CVR analysis, Flight 267 entered clouds and fogs. The altitude of Flight 267 was not sufficient enough to pass the mountains. The mountains were covered by fog at the time. It is plausible that their proximity to terrain was not noticed by them.
  The investigation team decided to investigate the crew's motivation to deviate from the flight's predicted flight path. They checked on the crew's previous flight from Sentani to Oksibil. It was revealed that the crew did exactly the same thing: making a direct left base by deviating from its predicted flight  path. Investigators then stated that the crew might have been overconfident with their flying skill. Similar to TransAsia Airways Flight 222, due to their previous success on landing an aircraft prior to the accident (by flying below the minimum safe altitude), the crew believed that they were able to do the same thing in the future without considering the consequences. The crew had accrued thousands of flight hours and were familiar with the airport. Because of their familiarity with the terrain, they tend to be confident with their skill. Thus, their situational awareness were reduced significantly.
  However, these were all preventable had the EGPWS sounded and warned the crew of their proximity to terrain. The NTSC noted that the EGPWS didn't sound at all during the flight's final moment, even though Flight 267 was going to hit the mountain. Investigators revealed that the circuit breaker which was responsible for the activation of the EGPWS had been pulled off by Flight 267's crew. Similar to the Mount Salak Sukhoi Superjet tragedy, the crew had shut down the EGPWS warning on purpose. Trigana Air's management personnel stated that some pilots had stated that the warnings sometimes sounded during inappropriate condition. This led some pilots to think that the EGPWS had malfunctioned. Thus, the EGPWS was de-activated by pulling the circuit breaker. The management had identified some pilots including the accident pilot of the pilot with behaviour of pulling the EGPWS's circuit breaker.
  As per the final report, the investigation concludes that the EGPWS power supply circuit 
  breaker was pulled during the accident flight and the two previous flights, explaining the absence of altitude call out during the two previous approaches and warning prior to the impact. Further investigation revea
caption: PK-YRN, the aircraft involved, in 2008
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