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6 August 1997 - Korean Air 801

Korean Air Flight 801 (KE801, KAL801) was a scheduled international passenger flight operated by Korean Air. The flight crashed on August 6, 1997, on approach to Antonio B. Won Pat International Airport, in the United States territory of Guam, killing 229[a] of the 254 people aboard. The aircraft crashed on Nimitz Hill in Asan-Maina, Guam, while on approach to the airport. The National Transportation Safety Board cites poor communication between the flight crew as probable cause for the air crash, along with the captain's poor decision-making on the non-precision approach.

Flight 801 departed from Seoul-Kimpo International Airport (now Gimpo International Airport) at 8:53 p.m. (9:53 p.m. Guam time) on August 5 on its way to Guam. The flight experienced some turbulence, but was uneventful until shortly after 1:00 a.m. on August 6, as the jet was preparing to land. There was heavy rain at Guam so visibility was considerably reduced and the crew attempted an instrument landing. The glideslope Instrument Landing System (ILS) for runway 6L was out of service. However, Captain Park believed it was in service, and at 1:35 am managed to pick up a signal that was later identified to be from an irrelevant electronic device on the ground. The crew noticed that the aircraft was descending very steeply, and noted several times that the airport "is not in sight." Despite protests from flight engineer Nam that the detected signal was not the glide-slope indicator, Park pressed on and at 1:42 am, the aircraft crashed into Nimitz Hill, slightly south of the community of Nimitz Hill Annex, about 3 nautical miles (3.5 mi; 5.6 km) short of the runway, at an altitude of 660 feet (200 m).

The U.S. National Transportation Safety Board (NTSB) investigated the accident.

A special weather observation made at 01:32, ten minutes before the impact, reported:

Wind 090° at 6 knots; visibility—7 miles; present weather—shower vicinity; sky condition—scattered 1,600 feet, broken 2,500 feet, overcast 5,000 feet [above ground level]; temperature—27° C; dew point—25° C; altimeter setting 29.85 inches Hg; remarks—showers vicinity northwest-northeast.

Another special weather observation made at 01:47, five minutes after the impact, reported:

Wind variable at 4 knots; visibility—5 miles; present weather—light rain shower; sky condition—few 1,500 feet, scattered 2,500 feet, overcast 4,000 feet; temperature 26° C; dew point 24° C; altimeter 29.85 inches Hg.

The crew had been using an outdated flight map that was missing a 724 foot obstruction symbol depicted at the NIMITZ VOR and that map stated the Minimum Safe Altitude while crossing the NIMITZ VOR for a landing aircraft was 1,300 feet (400 m) as opposed to the updated altitude of 1,440 feet (440 m). Flight 801 crashed near the NIMITZ VOR, which is situated on Nimitz Hill at a height of 680 feet (210 m) at 1:42 am, when it descended below the minimum safe altitude of 1,440 feet (440 m) during its landing approach. The report also identified that the captain may have mistakenly believed that the airplane was closer to the airport than it was and that there may have been confusion about the location of the Distance Measuring Equipment (DME) in relation to the airport, with the crew anticipating the VOR/DME to be located at the airport. The DME was sited at the NIMITZ VOR some 3.3 nmi (3.8 mi; 6.1 km) from the airport and such a configuration had not been part of Korean Air's simulator training, the crew's training for such non-precision approaches having been carried out in scenarios where the DME was located at the airport. Nevertheless, the correct DME distances were shown on the approach chart.

The NTSB was critical of the flight crew's monitoring of the approach, and even more critical of why the first officer and flight engineer did not challenge the captain for his errors. Even before the accident, Korean Air's Crew Resource Management program was already attempting to promote a free atmosphere between the flight crew, requiring the first officer and flight engineer to challenge the captain if they felt concerned. However, the flight crew only began to challenge the captain six seconds before impact, when the first officer urged the captain to make a missed approach. According to the cockpit voice recorder (CVR), the flight crew had suggested to the captain that he made a mistake, but did not explicitly warn him. The flight crew had the opportunity to be more aggressive in his challenge and the first officer even had the opportunity to take over control of the aircraft and execute a missed approach himself, which would have prevented the accident, but he did not do this. Despite examining Korean Air's safety culture and previous incidents, the NTSB was unable to determine the exact reasons why the flight crew failed to challenge the captain, but at the same time noted that "problems associated with subordinate officers challenging a captain are well known."

Air Traffic Control error also played a role in the accident. The approach controller, 39-year-old Kurt James Mayo, did not give a position advisory to the flight crew, which would have advised them to cross check their position on radar with that of other flight instruments. In addition, he was supposed to monitor the flight even after they switched to the tower frequency, which could have allowed him to alert the rescue response. Mayo did not monitor the flight on the terminal radar display which showed the terrain in the area because radar service had been terminated at the time. The tower controller, Marty Irvin Theobald (also 39), was also criticized for not alerting the crew, as Mayo had been unaware of the aircraft's low altitude, and did not provide an alert to him.

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

Transcript of Air Traffic communications


Guam CERAP: CERAPAgana FCT, Local Control: LCKorean Airline Flight 801: KAL801Ramp Control: RAMPAndersen 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 hasn't 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 haven't i ya
    he hasn't 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 don't have him he's not on my frequency
15.54.18 CERAP well i don't 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 he's 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 thates ryan
15.55.31 RAMP oh thates ryan coming in now
15.55.32 LC affirmative
15.55.33 RAMP o k ill (unintelligible)

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