This ATR 42 Should Not Have Been Here — What Happened?

Hello aviators, how are you today? My name is Magnar Nordal, and I am an instructor and former captain on ATR aircraft. 2026 began with some heartbreaking news. On 17 January, an ATR 42-500 operated by Indonesia Air Transport crashed into a mountain near Sultan Hasanuddin Airport in Makassar, located on Sulawesi Island in Indonesia. My heartfelt condolences go out to the families and colleagues of those affected. This is what we know so far: The aircraft was built in 2000 and delivered to Air Dolomiti in Italy. In 2010, it was transferred to Indonesia Air Transport and registered as PK-THT. It operated in a 46-seat passenger configuration for 15 years before being reconfigured into an airborne surveillance platform in April 2025. In this configuration, the aircraft was operating under contract for the Marine and Fisheries Resources Surveillance Agency. Indonesia Air Transport was established in 1968. The airline is headquartered at Halim Perdanakusuma International Airport in Jakarta. At present, it operates two Embraer Legacy 600 aircraft configured for VIP transport. On the accident flight, the aircraft departed Yogyakarta International Airport at 01:09 UTC (08:09 local time) with 11 people on board. It climbed to 11,000 feet and proceeded toward the Java Sea, where it later descended to 2,000 feet to conduct its mission. After completing the mission, the aircraft climbed to 6,000 feet and continued toward Sultan Hasanuddin Airport in Makassar. According to the Indonesian Ministry of Transport, Makassar Area Terminal Service Center cleared the ATR for an approach to Runway 21 at Sultan Hasanuddin Airport at 04:23 UTC (11:23 local time). Data from FlightRadar24 appears to support this, with the last recorded plot at 04:20 UTC. However, AirNav Indonesia reported that the aircraft disappeared from radar at 06:17 UTC (13:06 local time). The Ministry of Transport also stated that air traffic control observed the aircraft was not on the correct approach path and instructed the crew to adjust their flight path. Several additional course corrections were issued before contact was lost, approximately 11 nautical miles northeast of Runway 21. Local media later reported that a climber discovered debris at the foot of Mount Bulusaraung, which has an elevation of 5,135 feet. A picture showing a recovered page from the aircraft’s manual has been published. The page is about icing procedures. This triggered speculations that the aircraft encountered icing conditions, and that the crew consulted the manual in response. This interpretation is illogical for two reasons. First, the page in question addresses ground de-icing procedures, which apply when an aircraft is contaminated by snow or ice prior to takeoff. Second, in a tropical climate, icing conditions occur only at altitudes above 15,000 feet. On 18 January, the aircraft was located on the mountain. When plotting the position on the radar vectoring chart for Makassan, we can see the minimum altitude is 7,000 feet in the area the aircraft was found. This is the ILS approach chart for runway 21. The approach starts at waypoint COPAC, where the minimum altitude is 5000 feet. From there, the aircraft must track 165 degrees until intercepting the ILS localizer at 7. 9 NM from MAK VOR/DME. It is important the aircraft follows this procedure, as the terrain is high to the east Weather reports for the Airport between 04:30 and 06:30 UTC indicated westerly winds, good visibility, rain showers, cloud base around 1,700 feet, and cumulonimbus clouds present in the approach area for the entire period. And now to the question everyone wants answered: why did the aircraft crash? It is apparent the aircraft deviated from the planned track and hit high terrain outside the protected area. But why? That’s what the investigators will have to find out.

As a pilot who has flown the ATR 42-500, I can share some relevant information about the aircraft itself. The ATR 42-500 has an endurance of more than six hours. Therefore, whether the aircraft disappeared after three or five hours of flight, depending on the source, both scenarios fall well within the aircraft’s operational capabilities. Ultimately, endurance depends on the amount of fuel on board at departure. Does the aircraft have GPS? Yes, it’s the primary navigation system. Does the ATR 42-500 have a Ground Proximity Warning System? Yes, it does. The system consists of two subsystems. The first is based on a radio altimeter and provides warnings if the aircraft is descending rapidly toward the ground or flying toward rising terrain. The second subsystem is the Enhanced Ground Proximity Warning System, or EGPWS, which uses GPS and a global terrain database to alert the crew to high terrain ahead of the aircraft. Was there a technical failure? We do not know. Did the pilots lose situational awareness? Apparently, they did. Was weather a contributing factor? Possibly. The presence of cumulonimbus clouds indicates adverse weather conditions, but at this stage, it is unclear how, or to what extent, the weather affected the flight. Why did the crew not respond appropriately to air traffic control instructions? We do not yet know what was said on the radio frequency. Hopefully, the Flight Data Recorder and Cockpit Voice Recorder will provide answers. The role of the investigators is to collect factual information, analyse it, and draw conclusions. This process takes time. Hopefully, a preliminary report will be available within a month. Until then, we must remain patient. As always, a big thank you to the supporters of this channel. Thank you for watching.