Investigation Summary
The investigation highlighted a breakdown in Crew Resource Management (CRM). The captain, who was suffering from fatigue after being reassigned from a Dubai flight, mistakenly believed the glideslope was operational despite being briefed otherwise. During the localizer-only approach, the crew improperly descended below the intermediate approach altitudes of 2,000 feet and 1,440 feet (the step-down fix at the NIMITZ VOR) while still outside the required distance. The first officer and flight engineer failed to effectively challenge the captain's decision to descend. Furthermore, the FAA had inhibited the Minimum Safe Altitude Warning (MSAW) system at Guam due to frequent false alarms, which prevented air traffic controllers from receiving a low-altitude alert that could have warned the crew 64 seconds before impact.
Final Conclusions
The NTSB determined the probable cause was the captain's failure to adequately brief and execute the non-precision approach, and the flight crew's failure to monitor the approach. Contributing factors included the captain's fatigue, inadequate CRM training at Korean Air, and the FAA's intentional inhibition of the MSAW system at Guam.
Video Analysis
Korean Air Flight 801: Controlled Flight into Terrain on Guam — Analysis of the 1997 Boeing 747 crash on Nimitz Hill caused by pilot confusion over a disabled glideslope and descent below minimum altitude during heavy rain.
If playback is blocked, the owner has disabled embedding — use the link above.
Crew Experience
Captain
The captain had close to 9,000 hours of flight time, including 3,192 on the Boeing 747
First Officer
The first officer was 40-year-old Song Kyung-ho, who had more than 4,000 hours flying experience, with 1,560 of them on the Boeing 747.
Flight Engineer
The flight engineer was 57-year-old Nam Suk-hoon, a veteran pilot with more than 13,000 flight hours, 1,573 of which were on the Boeing 747.
Systems & Failure Modes
GPWS
Ground Proximity Warning System; provided 'Sink Rate' and 'Pull Up' warnings 6 seconds before impact.
MSAW
Minimum Safe Altitude Warning; a ground-based safety tool that was inhibited by the FAA at Guam at the time of the accident.
ILS Glideslope
The vertical guidance component of the Instrument Landing System, which was known to be inoperative.
Interesting Facts
- 01The glideslope for Runway 06L was officially out of service for maintenance.
- 02The captain was originally scheduled for a flight to Dubai but was reassigned due to rest requirements.
- 0326 people survived the initial impact and post-crash fire, though one later died of injuries.
- 04The Minimum Safe Altitude Warning (MSAW) system at Guam was inhibited and did not alert controllers.
- 05The aircraft struck Nimitz Hill approximately 3.3 nautical miles from the runway threshold.
- 06The captain improperly descended below the 1,440-foot step-down fix while still outside the NIMITZ VOR.
- 07The emergency response was delayed by nearly an hour due to the remote location and poor coordination between agencies.
Safety Actions & Advisories
MSAW Configuration
The FAA was mandated to review and correctly configure MSAW systems at all airports to prevent unnecessary inhibition.
Korean Air CRM Overhaul
Korean Air implemented significant changes to its pilot training and Crew Resource Management programs to address hierarchical communication issues.
Terrain Awareness Systems
Accelerated the adoption of Enhanced GPWS (EGPWS) which provides a forward-looking terrain display.
Location
ACCIDENT SITE · Coordinates taken from the wikidata coordinate.