Page:KAL801Finalreport.pdf/186



 After the flight crew made an initial sighting of Guam, Korean Air flight 801 encountered instrument meteorological conditions as the flight continued on its approach to Guam International Airport. Although flight 801 likely exited a heavy rain shower shortly before the accident, the flight crew was still not able to see the airport because of the presence of another rain shower located between Nimitz Hill and the airport. By not fully briefing the instrument approach, the captain missed an opportunity to prepare himself, the first officer, and the flight engineer for the relatively complex localizer-only approach and failed to provide the first officer and flight engineer with adequate guidance about monitoring the approach; therefore, the captain's approach briefing was inadequate. The captain's expectation of a visual approach was a factor in his incomplete briefing of the localizer approach. For flights conducted at night or when there is any possibility that instrument meteorological conditions may be encountered, the failure to fully brief an available backup instrument approach compromises safety. The Korean Air airport familiarization video for Guam, by emphasizing the visual aspects of the approach, fostered the expectation by company flight crews of a visual approach and, by not emphasizing the terrain hazards and offset DME factors, did not adequately prepare flight crews for the range of potential challenges associated with operations into Guam. The challenges associated with operations to Guam International Airport support its immediate consideration as a special airport requiring special pilot qualifications. <li>Although the captain apparently became confused about the glideslope's status, the flight crew had sufficient information to be aware that the glideslope was unusable for vertical guidance and should have ignored any glideslope indications while executing the nonprecision localizer-only approach.</li> <li>Navigation receivers, including glideslope receivers, may be susceptible to spurious radio signals.</li> </ol>