Turkish Airlines Flight 634: A Night‑time Tragedy Over Diyarbakır

On January 8, 2003, the skies above the historic city of Diyarbakır turned deadly when Turkish Airlines Flight 634 vanished from radar during a routine night‑time approach. The accident, which claimed the lives of nine people, remains a stark reminder of the challenges posed by night operations, terrain awareness, and human factors in aviation.

Flight Profile and Final Moments

Flight 634 was a scheduled domestic service operated by a British Aerospace Jetstream 31 turboprop. After departing from Istanbul’s Atatürk Airport, the aircraft was bound for Diyarbakır Airport, a destination surrounded by rugged hills and subject to rapidly changing weather conditions.

Night Approach and Weather

The flight entered the final approach phase shortly after 22:30 local time. Weather reports indicated light to moderate snowfall and reduced visibility, typical for the region during winter months. Although the runway at Diyarbakır is equipped with instrument landing system (ILS) guidance, the combination of darkness, snowfall, and the surrounding terrain created a demanding environment for the flight crew.

Sequence of Events

  1. The aircraft was cleared for a standard ILS approach to runway 23.
  2. Shortly after beginning the descent, the crew reported a deviation from the glide path.
  3. Air traffic control instructed a go‑around, but the aircraft failed to regain a safe altitude.
  4. Contact with the aircraft was lost at approximately 22:41 UTC, and the wreckage was later located on the slopes of a nearby hill, approximately three nautical miles from the runway threshold.

Investigation Findings

The Turkish Directorate General of Civil Aviation (DGCA) led a comprehensive investigation, supported by the Aircraft Accident Investigation Board (AAIB) and international experts. The final report identified several contributing factors, with pilot error highlighted as the primary cause.

Human‑Factor Analysis