What happened
On 26 September 1997, Garuda Indonesia flight GA 152, an Airbus A300-B4 registered PK-GAI, departed Jakarta Soekarno-Hatta International Airport for a scheduled service to Medan. During the flight, the crew received briefings regarding degraded visibility due to smoke, with reports suggesting visibility as low as 400 meters. Additionally, a NOTAM had advised caution when using the Medan VOR due to maintenance issues and restricted radial alignment.
As the aircraft approached Medan, the crew was navigating under Instrument Flight Rules. During the descent phase, air traffic controllers provided a series of heading instructions to vector the aircraft for an ILS approach to Runway 05. At 06:30:04, the crew received an instruction to turn right to a heading of 046 degrees. However, the crew misread the instruction as a heading of 040 degrees and began a left turn instead.
During the confusion, the flight crew engaged in several communications with Medan Approach to clarify whether they should be turning left or right. While the aircraft eventually began to roll right, it continued to descend below the assigned altitude. At 06:31:32, the aircraft struck trees at an elevation of approximately 1550 feet. The aircraft then impacted the floor of a ravine roughly 600 meters further along the flight path. The accident resulted in 234 fatalities, with no survivors.
Findings
Data from the flight recorder indicates that the aircraft was in a descent and performing a left turn when the initial tree impact occurred. The investigation highlighted a misinterpretation of air traffic control heading instructions by the flight crew, which led to the aircraft descending below the safe altitude into terrain.