JAL B763 near Seoul on Sep 12th 2014, upset injures 7 cabin crew

Last Update: May 28, 2015 / 14:26:56 GMT/Zulu time

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Incident Facts

Date of incident
Sep 12, 2014

Classification
Accident

Airline
JAL Japan Airlines

Departure
Tokyo Haneda, Japan

Destination
Seoul Gimpo, South Korea

Aircraft Registration
JA654J

Aircraft Type
Boeing 767-300

ICAO Type Designator
B763

Airport
Gimpo International Airport, Seoul

Airport ICAO Code
RKSS

A JAL Japan Airlines Boeing 767-300, registration JA654J from Tokyo Haneda (Japan) to Seoul Gimpo (South Korea), was descending through FL160 about 50nm southeast of Seoul when the aircraft encountered an upset that caused injuries to 7 cabin crew. The aircraft continued for a safe landing at Seoul's Gimpo Airport about 17 minutes later at 17:51L (08:51Z). The injured were taken to hospitals.

Japan's TSB reported that one cabin crew was in hospital for two weeks, the 6 others received cervical sprains. The JTSB reported they received unconfirmed information that three passengers may have received injuries as well, the JTSB is attempting to get more information. The JTSB did not report what caused the upset.

On May 28th 2015 the JTSB released their final report concluding the probable cause of the accident was:

In this accident, it is highly probable that the aircraft was strongly shaken because it encountered turbulence when flying at around 16,000 ft, causing cabin crewmembers thrown into the air to hit the ceiling, and one of them fell onto the floor on her back to sustain a severe injury.

It is highly probable that the turbulence the aircraft encountered was caused by the redeveloped convective clouds after once shrinking. It is probable that the pilots were unable to capture the echoes of the convective clouds in their early developing stages which existed in its flight direction (forward and downward of the aircraft) due to having set the antenna tilt angle of the airborne weather radar to auto mode.

The JTSB reported that airline operations had informed the flight crew enroute that there were no thunderstorm cells visible that would require deviation around. The captain thus had informed cabin crew, that he would turn the fasten seat belt sign on at FL100 as usual. During the descent towards Seoul the weather radar did not paint returns, however, at about 16,000 feet a clearly visible cloud came into view with no time to avoid it, the aircraft entered the cloud and experienced a vertical acceleration of +1.5G for about 2 seconds, then the vertical acceleration changed to -0.2G followed by +1.3G, there was little change in the pitch attitude of the aircraft, autopilot and autothrottle remained engaged throughout the event.

At the time of the turbulence encounter cabin service had already finished and the flight attendants were working in the aft galley. One flight attendant received serious, 6 others minor injuries.

The JTSB described the weather situation: "According to the upper-laid observation weather chart (500 hPa, 700 hPa and 850 hPa) of 09:00 and 21:00 of the Japan Meteorological Agency, the Korean Peninsula area had been covered with the rear surface of the cold air trough. Although the center of the cold air had moved to the east, it was under the condition that cold air stayed as about -10 °C at around 500 hPa. According to the images of the Terminal Doppler Weather Radar (TDWR) installed in Incheon International Airport (Korea), small echoes had been scattered to the west of GUKDO (123 km southeast of Incheon TDWR), these echoes attenuated once. However, they began to grow up near GUKDO from past 17:00."

Metars:
RKSS 121100Z 06005KT 5000 HZ FEW030 BKN180 21/16 Q1013 NOSIG
RKSS 121000Z 31004KT 6000 FEW030 BKN180 24/15 Q1013 NOSIG
RKSS 120900Z 29004KT 6000 FEW030 BKN140 24/15 Q1013 NOSIG
RKSS 120800Z 27005KT 6000 SCT030 BKN140 24/15 Q1012 NOSIG
RKSS 120713Z 21002KT 7000 FEW020 SCT030 BKN180 24/15 Q1012 NOSIG
RKSS 120700Z 10011KT 6000 -SHRA FEW020 SCT030 BKN180 23/14 Q1012 BECMG NSW
RKSS 120642Z 22007G22KT 6000 1000NW SHRA FEW020 SCT030 BKN180 23/16 Q1013 WS ALL RWY BECMG NSW
RKSS 120647Z 15013G29KT 4000 1000NW SHRA FEW020 SCT030 BKN180 21/13 Q1012 NOSIG
RKSS 120600Z 20005KT 9999 FEW030 BKN180 26/15 Q1012 NOSIG
RKSS 120500Z 19003KT 330V050 9999 FEW020 BKN180 27/14 Q1012 NOSIG