What happened
While performing a scheduled cargo transport from Singapore-Changi Airport, an aircraft carrying mail, software, and textiles was conducting an NDB approach to runway 33 at Kayell. During the flight, air traffic control issued an instruction to descend to 2,400 feet. However, the crew misheard this command as a descent to 400 feet.
As the aircraft continued its descent below the required minimum altitude of 2,400 feet, it collided with trees on a forested slope near the village of Puchong, situated approximately 14 km from the airport. The impact resulted in the total destruction of the aircraft and four fatalities among the crew.
Findings
Investigations into the accident identified several contributing factors related to cockpit management and communication. Although the Ground Proximity Warning System (GPWS) activated within the cockpit, the crew did not take the necessary corrective actions. The investigation also noted that the crew did not follow established approach checklists or published procedures.
Further complications included non-standard phraseology from air traffic control, which led to the critical misinterpretation of the descent altitude. Additionally, poor coordination among the crew and limited visibility at the time of the accident played significant roles in the sequence of events.