What happened
A Tupolev 134 was operating a flight from Mbala, Zambia, to Maputo, Mozambique. During the descent toward the destination, the flight crew mistakenly tuned into the frequency for the Matsapa VOR. This navigational error led to an unintended 37-degree turn during the approach phase.
While the pilot expressed concern regarding the deviation, the crew did not utilize other available instruments to confirm their position. The aircraft continued its descent into an area where visibility was limited by darkness and cloud cover, eventually dropping below the 3000-foot altitude limit without establishing visual contact with the airfield. During this period, the crew mistakenly believed a power failure had occurred at Maputo.
Despite a GPWS warning that lasted for 32 seconds, the descent continued until the aircraft struck the terrain at 2187 feet. The impact caused the plane to bounce and crash into an upward slope, leading to the structural breakup of the airframe. The wreckage slid across the border between South Africa and Eswatini and subsequently ignited. There were 34 fatalities among the occupants.
Findings
The investigation determined that the crew failed to adhere to established procedures for an instrument let-down approach. Specifically, the crew continued to descend under visual flight rules despite having no visual contact with the ground. This descent below minimum safe altitude was compounded by the fact that the crew ignored the GPWS alarm.