6 August 1997 - Korean Air 801

The aircraft, a Boeing 747-300 with registration HL7468, was conducting a night-time approach to Guam runway 06L. Because of the unavailability of the ILS glide slope system (due to upgrading of the system), a VOR/DME approach was flown. Flight 801 had descended 800ft below the prescribed altitude, struck the 709ft Nimitz Hill at a height of 650ft and crashed in a jungle valley, breaking up and bursting into flames. The aircraft ended up at a height of 560ft, 250m from the UNZ VORTAC (located on the top of Nimitz Hill). It was established a.o. that the software fix for the Minimum Safe Altitude Warning (MSAW) system at Agana Center Radar Approach Control (CERAP) had rendered the program useless. A software patch had been installed since there had been complaints of the high rate of false MSAW alarms at Guam. This made KAL801's descent below MDA go undetected at the Agana CERAP.

Special Link: Radar Data with selected ATC and CVR communication excerpts

Transcript of the Cockpit Voice Recorder (CVR)


Agana FCT, Local Control: LC
Korean Airline Flight 801: KAL801
Ramp Control: RAMP
Andersen AFB Control Tower: Andersen

15.38.06 CERAP inbound
15.38.12 LC agana tower
15.38.13 CERAP twelve west korean air eight zero one seven forty
    seven i I s six left k m
15.38.18 LC understand seven four
15.38.20 CERAP thats what i show
15.38.22 LC all right thanks t o
15.39.23 CERAP km
15.41.07 KAL801 agana tower korean air eight zero one ah
    (unintelligible) localizer six left
15.41.14 LC korean air eight zero one heavy agana tower runway
    six left---wind-zero niner zero at seven cleared to
    land verify heavy boeing seven four seven tonight
15.41.26 KAL801 korean eight zero one roger (unintelligible) six left
15.41.30 LC korean eight zero one heavy roger
15.44.02 CERAP was that nine eighty eight youre looking for
15.44.07 LC say again
15.44.09 CERAP guam to saipan is that nine eighty eight
15.44.11 LC affirmative
15.44.12 CERAP yeah i think we lost a flight plan so im just gonna
    make one up here---oops
15.44.18 LC ah he hadnt called me yet so they may not have
    put it in either he may have they may have cancelled
15.44.23 CERAP ok
15.44.24 LC why dont we just hold off till he calls for it
15.44.26 CERAP km
15.44.28 LC to
15.45.25 LC korean air eight zero one heavy tower how do
    you hear
15.47.03 RAMP this is juan
15.47.05 LC yeah korean air eight zero one heavy ah---aircraft
    change on the type is that a permanent change
15.47.11 RAMP ah no thats just ah one of those temporary deals
15.47.14 LC is that one of the temporaries
15.47.15 RAMP yeah they they their normal is an airbus its just
    i guess
15.47.19 LC yeah
15.47.19 RAMP they have more passengers this time around
15.47.21 LC all right what gate is he on
15.47.22 RAMP ah hes going to gate twelve
15.47.23 LC all right thanks t o
15.47.24 RAMP (unintelligible)
15.48.05 LC korean air eight zero one heavy agana tower
15.49.51 RAMP this is juan
15.49.52 LC yeah korean air come up to you
15.49.53 RAMP ah no
15.49.54 LC all right thanks t o
15.49.55 RAMP *(all right)
15.49.56 LC approach agana
15.50.15 LC korean air eight zero one heavy agana tower
15.50.23 LC approach agana did korean air come back to you
15.50.28 CERAP eight zero one
15.50.29 LC affirmative
15.50.35 CERAP no
15.50.35 LC he checked in with me i cleared him to land i
    dont know where hes at--never did have him in
15.50.41 RAMP you never saw him
15.50.45 CERAP he didnt land
15.50.46 LC negative
15.50.50 CERAP oh my god
15.50.52 LC stand by a second
15.50.58 RAMP this is juan
15.51.00 LC yeah did korean air
15.51.01 RAMP no in fact im listening to cerap i dont even hear eight
    zero one i can hear you on the radio
15.51.06 LC yeah i tried to get a hold of him he called me ah
    i cleared him to land
15.51.09 RAMP yeah (unintelligible)
15.51.10 LC i never had him in sight
15.51.11 RAMP (unintelligible) you said cleared to land and i was
    looking around and i said wheres he at and thats
15.51.14 LC yeah i never had him in sight hold on a second
15.51.17 LC andersen tower agana tower
15.51.18 CERAP dont see him on the radar
15.51.27 LC i dont see him either standby a second
15.51.30 Andersen go ahead
15.51.31 LC you didnt have a boeing seven forty seven land up
    there did you
15.51.35 Andersen just now
15.51.36 LC affirmative
15.51.37 Andersen hu hu ah no i dont have any lights on so i dont i dont
    see anybody out there
15.51.41 LC well we're missing a boeing seven forty seven stand
15.51.45 LC just checked with andersen they dont know where
    hes at either
15.51.49 CERAP is it raining out there
15.51.50 LC i got wet runway but ah--ive got a small ah shower
    pushing through but i dont have ah but i can see the
    approach end---standby a second
15.52.04 LC korean air eight zero one heavy agana tower
15.52.16 LC is that him talking to you
15.52.19 CERAP negative
15.52.26 LC i dont have him---he called me once i cleared him to
    land told him not in sight and i dont have him
15.52.34 CERAP well he must have crashed then
15.52.38 LC korean air eight zero one heavy agana tower
15.52.45 CERAP I'll talk to you later
15.52.46 LC to
15.52.47 LC you there---i do not have him---not in sight and i
    have a shower pushing through the field now im
    losing my visby
15.53.22 RAMP (unintelligible) *(lost him)
15.53.24 LC why we dont know where hes at we're still looking for
15.53.27 RAMP what about cerap cerap
15.53.28 LC center doesnt have him either he hasnt gone back to
    center center doesnt have him on the radar
15.53.33 RAMP yeah last time he was with you right he was about
    what---ten out
15.53.37 LC something like that
15.53.38 RAMP yeah cause i heard you say you said not in sight but it
    sound like he was already ten out or something---from
    the time cerap let him go
15.53.45 LC yeah um he hasnt called you on your frequency
15.53.47 RAMP no
15.53.48 LC all right thanks
15.53.49 RAMP ok
15.53.50 LC approach agana
15.53.55 CERAP center
15.53.56 LC yeah i just checked with ramp they a ah havent i ya
    he hasnt called them either
15.54.02 CERAP well---he must have crashed then west of the airport
15.54.08 LC he was what ah about twelve out when you gave him
    to me ten or twelve out when you gave him to me
15.54.12 CERAP yes
15.54.14 LC o k i dont have him hes not on my frequency
15.54.18 CERAP well i dont know how you can have--somebody
    search west of the airport for the airplane
15.54.25 LC whos that ah inbound
15.54.27 CERAP I'll ask ryan
15.54.28 LC thanks t o
15.54.30 LC korean air eight zero one heavy agana tower
15.55.10 CERAP tower center inbound
15.55.13 LC agana tower
15.55.14 CERAP six south ryan seven eighty nine visual runway six left
15.55.17 LC is he gonna be able to go out and take a look
15.55.19 CERAP yeah hes looking now
15.55.26 LC thanks t o
15.55.28 LC tower tower
15.55.28 RAMP is that him behind you
15.55.29 LC no thats ryan
15.55.31 RAMP oh thats ryan coming in now
15.55.32 LC affirmative
15.55.33 RAMP o k ill (unintelligible)

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