Investigation Summary
The accident occurred during a period of deteriorating weather at Mokpo Airport, which lacked an Instrument Landing System (ILS) and relied on VOR/DME non-precision approaches. After two failed landing attempts, the crew initiated a third approach. During this final attempt, the aircraft was significantly below the required profile: at the 4.0 nautical mile final approach fix, where the altitude should have been 1,600 feet, the aircraft had already descended to approximately 700 feet. The investigation revealed that the crew was improperly using the Flight Management Computer (FMC) to execute the non-precision approach; a critical 1.5-mile final waypoint had not been correctly entered, leading the crew to believe they were closer to the runway than they actually were. This reliance on automated systems for a manual, non-precision procedure in poor visibility led to the premature descent. Furthermore, the captain had limited experience at Mokpo and a history of unsatisfactory proficiency checks, which likely hindered his ability to recognize the altitude deviation.
Final Conclusions
The South Korean Civil Aviation Bureau concluded the primary cause was the captain's violation of standard operating procedures by descending below the minimum descent altitude (MDA) while visibility was below the required 2,800 meters. Contributing factors included poor crew coordination (CRM), the captain's lack of experience with the specific challenges of Mokpo Airport, and the absence of precision approach lighting or ILS at the facility.
Video Analysis
The Crash of Asiana Airlines Flight 733 — A detailed look at the 1993 crash of Asiana Airlines Flight 733 near Mokpo, South Korea, which resulted in 68 fatalities following multiple failed landing attempts in poor weather.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Systems & Failure Modes
VOR/DME
The primary navigation aid at Mokpo; the crew failed to follow the altitude constraints associated with this non-precision approach.
GPWS
The Ground Proximity Warning System alerted the crew to terrain and minimums approximately 30 seconds before impact.
FMC
Flight Management Computer; investigators suggested a waypoint error may have led the crew to believe they were closer to the runway than they were.
Interesting Facts
- 01The crash was the first hull loss of a Boeing 737-500 series aircraft.
- 02Mokpo Airport's runway was only 1,500 meters long and lacked an Instrument Landing System (ILS).
- 03The captain had only one previous official landing experience at Mokpo Airport.
- 04The aircraft struck the mountain at 800 feet, while the peak of the ridge was 1,050 feet.
- 05Two survivors managed to walk to a nearby village branch office to alert authorities of the crash.
Safety Actions & Advisories
Airport Infrastructure Upgrades
The accident highlighted the dangers of operating jet aircraft into airports lacking precision approach aids, leading to calls for ILS installations at regional South Korean airports.
Crew Training and CRM
Asiana Airlines faced scrutiny over its pilot training programs, specifically regarding non-precision approach proficiency and cockpit resource management.