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Controlled flight into terrain, Korean Air Flight 801, Nimitz Hill, Guam, August 6, 1997
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Event Summary

Board Meeting : Controlled flight into terrain, Korean Air Flight 801, Nimitz Hill, Guam, August 6, 1997
11/2/1999 12:00 AM

Executive Summary

On August 6, 1997, about 0142:26 Guam local time, Korean Air flight 801, a Boeing 747-3B5B (747-300), Korean registration HL7468, operated by Korean Air Company, Ltd., crashed at Nimitz Hill, Guam. Flight 801 departed from Kimpo International Airport, Seoul, Korea, with 2 pilots, 1 flight engineer, 14 flight attendants, and 237 passengers on board. The airplane had been cleared to land on runway 6 Left at A.B. Won Guam International Airport, Agana, Guam, and crashed into high terrain about 3 miles southwest of the airport. Of the 254 persons on board, 228 were killed, and 23 passengers and 3 flight attendants survived the accident with serious injuries. The airplane was destroyed by impact forces and a postcrash fire. Flight 801 was operating in U.S. airspace as a regularly scheduled international passenger service flight under the Convention on International Civil Aviation and the provisions of 14 Code of Federal Regulations Part 129 and was on an instrument flight rules flight plan.

The National Transportation Safety Board determines that the probable cause of the Korean Air flight 801 accident was the captain's failure to adequately brief and execute the nonprecision approach and the first officer's and flight engineer's failure to effectively monitor and cross-check the captain's execution of the approach. Contributing to these failures were the captain's fatigue and Korean Air's inadequate flight crew training. Contributing to the accident was the Federal Aviation Administration's (FAA) intentional inhibition of the minimum safe altitude warning system (MSAW) at Guam and the agency's failure to adequately manage the system.

The safety issues in this report focus on flight crew performance, approach procedures, and pilot training; air traffic control, including controller performance and the intentional inhibition of the MSAW system at Guam; emergency response; the adequacy of Korean Civil Aviation Bureau (KCAB) and FAA oversight; and flight data recorder documentation. Safety recommendations concerning these issues are addressed to the FAA, the Governor of the Territory of Guam, and the KCAB.


As a result of the investigation of the Korean Air flight 801 accident, the National Transportation Safety Board makes recommendations to the Federal Aviation Administration, the Governor of the Territory of Guam, and the Korean Civil Aviation Bureau.

To the Federal Aviation Administration:

Require principal operations inspectors assigned to U.S. air carriers to ensure that air carrier pilots conduct a full briefing for the instrument approach (if available) intended to back up a visual approach conducted at night or when instrument meteorological conditions may be encountered. (A-00-7)

Consider designating Guam International Airport as a special airport requiring special pilot qualifications. (A-00-8)

Disseminate information to pilots, through the Aeronautical Information Manual, about the possibility of momentary erroneous indications on cockpit displays when the primary signal generator for a ground-based navigational transmitter (for example, a glideslope, VOR, or nondirectional beacon transmitter) is inoperative. Further, this information should reiterate to pilots that they should disregard any navigation indication, regardless of its apparent validity, if the particular transmitter was identified as unusable or inoperative. (A-00-9)

Conduct or sponsor research to determine the most effective use of the monitored approach method and the maximum degree to which it can be safely used and then require air carriers to modify their procedures accordingly. (A-00-10)

Issue guidance to air carriers to ensure that pilots periodically perform nonprecision approaches during line operations in daytime visual conditions in which such practice would not add a risk factor. (A-00-11) Develop a mandatory briefing item for all air traffic controllers and air traffic control (ATC) managers, describing the circumstances surrounding the performance of the Combined Center/Radar Approach Control controller in this accident to reinforce the importance of following ATC procedures. (A-00-12)

Require that all air carrier airplanes that have been equipped with on-board navigational systems capable of providing vertical flightpath guidance make use of these systems for flying nonprecision approaches whenever terrain factors allow a constant angle of descent with a safe gradient. (A-00-13)

Require, within 10 years, that all nonprecision approaches approved for air carrier use incorporate a constant angle of descent with vertical guidance from on-board navigation systems. (A-00-14)

Include, in nonprecision approach procedures, tabular information that allows pilots to fly a constant angle of descent by cross-referencing the distance from the airport and the barometric altitude. (A-00-15)

Evaluate the benefits of depicting terrain and other obstacles along a specific approach path on the profile view of approach charts and require such depiction if the evaluation demonstrates the benefits. (A-00-16)

Provide user groups, along with Federal Aviation Administration Form 8260, draft plan and profile views of instrument procedures to assist the groups in effectively evaluating proposed new procedures. (A-00-17)

Consider the accident and incident history of foreign air carriers as a factor when evaluating the adequacy of a foreign civil aviation authority's oversight and whether a reassessment may be warranted. (A-00-18)

To the Governor of the Territory of Guam:

Form, within 90 days, a task force comprising representatives from all emergency response agencies on the island, including the appropriate departments within the government of Guam, Federal Aviation Administration, Guam International Airport Authority, U.S. Navy, U.S. Air Force, U.S. Coast Guard, Federal Emergency Management Agency, and all other affected agencies, to define and coordinate emergency notification and response procedures to ensure that timely emergency notifications are made to all local and Federal agencies according to need, location, and response time capability. (A-00-19)

Require periodic and regularly scheduled interagency disaster response exercises, including an off-airport aircraft accident scenario, in addition to those response drills already required at Guam International Airport in accordance with 14 Code of Federal Regulations Section 139.325. (A-00-20)

To the Korean Civil Aviation Bureau:

Require Korean Air to revise its video presentation for Guam to emphasize that instrument approaches should also be expected and describe the complexity of such approaches and the significant terrain along the approach courses and in the vicinity of the airport. (A-00-21)

Enter the YouTube ID of each video separated by a semi-colon (;). Example: "LV5_xj_yuhs; QgaTQ5-XfMM; VWW8DMpfI9U; BgAlQuqzl8o;"


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