Garuda Indonesia Flight 152

Garuda Indonesia Flight 152 was a scheduled domestic flight operated by Garuda Indonesia from Soekarno–Hatta International Airport, Tangerang, Indonesia, to Polonia International Airport, Medan, Indonesia. On 26 September 1997, the Airbus A300 flying the route crashed into mountainous woodlands near the village of Buah Nabar, Sibolangit, killing all 222 passengers and 12 crew members on board. It is the deadliest aviation disaster in Indonesia's history, and the fourth-deadliest involving an Airbus A300.

Accident

At 1:13 pm (local time), air traffic controllers in Medan cleared Flight 152 for an ILS approach to Runway 5 from its 316 degree heading. The crew, led by Captain Hance Rachmo Wiyogo (41), a pilot with 19 years of flying experience at Garuda Indonesia and nearly 12,000 flying hours, and First Officer Tata Zuwaldi (also 41), a former flight engineer who recently upgraded to pilot, were instructed to turn left to a heading of 240 degrees so as to intercept the ILS localizer. Two minutes prior to impact, the crew was asked to turn further left, to 215 degrees. At 1:30 pm, Medan instructed the crew to descend to 2,000 ft, and to turn right heading 046 degrees to line up for arrival into runway 05, and asked the crew to report their heading. Air traffic controllers then became confused as to which plane they were talking to, as another flight with the same number (Merpati Nusantara Airlines Flight 152) was also in the area at the time.

Earlier in the day, another Flight 152, Merpati Nusantara Airlines Flight 152, was handled by the same air traffic controller. This led to the controller mistakenly saying "Merpati one five two turn left heading 240 to intercept runway zero five from the right side"; as the wrong call sign was used, the Garuda pilots disregarded these instructions. The controller, on not receiving a response, queried the pilots to get their attention, this time using the correct call sign, "Indonesia 152". The controller then repeated most of his instructions, but specifically failing to repeat that the flight would be making its approach on the south side of the runway, or right side. The pilots believed they were flying the approach on the north side of the airport, which reflected the information on the approach chart the pilots were using. Thus, when the pilots were instructed to turn right to a heading of 046 maintaining 2,000 ft to capture the localizer for the ILS to runway 05, out of habit – or possibly due to the detailed approach chart – the captain initiated a left turn to a heading of 046. The First Officer was distracted during the turn and did not notice for a while that the aircraft was turning left. When he did notice, he told the captain he was turning the wrong way, and the captain questioned the controller over which way they needed to turn, to which the controller confirmed they were to turn right. A confusing conversation took place over which way to turn, with the controller not having a clear picture of what the flight was doing, due to being unaware that he had left out some critical instructions after his "Merpati 152" mistake and due to the Medan radar system having a refresh time of 12 seconds.

Without a constant up-to-date view of the flight's heading, the controller thought the plane was continuing left, when it was actually turning right and over high terrain. During this time the flight descended below 2,000 feet, probably due to the captain inputting the wrong altitude. The pilots did not notice this while they were focused on turning to the correct heading. Five seconds prior to initial impact with the treetops, the First Officer made a comment about the airplane's altitude. The FDR recorded increases in pitch and engine power, likely commanded by the crew in an effort to correct their altitude. Shortly before the recording ended, the cockpit voice recorder registered the sound of the plane striking trees, followed by shouting from the pilots. The aircraft crashed into a ravine 27 km from the runway 05 threshold, 18 km to the south of the center line. The aircraft hit the ground at 1:32 p.m., right wing low, turning towards the airport in the process at a heading of 230-240 degrees and an altitude of 1,550 ft MSL. All 234 people on board were killed.