Investigation Summary
The flight was operating a domestic scheduled service from Palembang to Medan. During the approach to Polonia International Airport, the crew was cleared for an NDB approach to runway 05. The pilots encountered difficulties with navigation, reporting to air traffic control that the 'ON' non-directional beacon was unreliable. Consequently, the captain elected to maintain 9,300 feet until passing the beacon. However, shortly after this communication, the pilot reported they were maintaining 6,000 feet until overhead the 'ON' NDB. The aircraft subsequently struck the 7,200-foot-high Mount Sibayak at an elevation of 5,560 feet. The wreckage was located by search and rescue aircraft the following day, with no survivors among the 57 passengers and 4 crew members.
Final Conclusions
The investigation concluded the accident was a Controlled Flight Into Terrain (CFIT). Contributing factors included bad weather and low clouds which obscured the mountainous terrain. The crew initiated a premature descent below the safe altitude for the approach path while navigating in instrument conditions with unreliable ground-based navigation aids.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain
AE Lontoh. Joined Garuda in May 1969.
Systems & Failure Modes
NDB (Non-Directional Beacon)
The pilot reported the 'ON' beacon was unreliable, which may have contributed to navigational errors during the approach.
CVR/FDR
Search teams recovered the cockpit voice recorder and flight data recorder to assist in the investigation.
Interesting Facts
- 01The aircraft was named Mamberamo and was seven years old at the time of the crash.
- 02The aircraft's manufacturer serial number (MSN) was 11055.
- 03The aircraft was previously registered as PK-GJV before being re-registered as PK-GVE in July 1974.
- 04The impact occurred at 5,560 feet on a volcano that rises to 7,200 feet.
- 05The pilot reported the NDB (Non-Directional Beacon) was unreliable shortly before the crash.
- 06This was the second Garuda Fokker F28 lost to CFIT in 1979, following the crash of PK-GVP in March.
- 07The airline paid 3.4 million Rupiah in compensation to the families of each victim.
Safety Actions & Advisories
Navigation Aid Reliability Review
Following reports that the 'ON' NDB was unreliable during the approach, authorities reviewed the maintenance and calibration of ground-based navigation aids in the Medan area to ensure accuracy for instrument approaches.