A JAL Japan Airlines Boeing 787-8, registration JA843J performing flight JL-774 from Melbourne,VI (Australia) to Tokyo Narita (Japan) with 146 passengers and 11 crew, was descending through about FL170 towards Tokyo when the aircraft encountered severe turbulence causing injuries to 4 flight attendants. The aircraft continued for a safe landing on Narita's runway 16L about 35 minutes later.
Japan's Ministry of Transport reported one flight attendant received a fracture of the lower right thigh, 3 others received sprains. The JTSB is investigating the occurrence.
On Apr 4th 2024 the JTSB reported the aircraft became unstable while descending through 5200 meters about 150km southeast of Narita Airport. One flight attendant sustained serious, three minor injuries. The JTSB opened an investigation.
On Jul 10th 2026 the JTSB released their final report concluding the probable causes of the accident were:
The JTSB concludes that it is most likely that the aircraft was shaken by disturbances caused by the convective activity from cumulus clouds, which resulted in the cabin crew member (R4), who was working in the aft galley, being lifted into the air in an unsteady posture and losing balance on landing, which caused serious injury.
The cabin crew member (R4) was working in the aft galley when the aircraft encountered turbulence. It most likely contributed to this that the flight crew members did not inform the cabin crew members of the change to the planned time for the fasten seat belt sign.
The JTSB analysed:
(1) Aircraft's Shaking
The JTSB concludes that, according to the EAFR records, the aircraft was more likely to have shaken significantly during its descent near FL 170 between 15:29:55 and 15:29:57.
(2) Weather Conditions
The JTSB concludes that, based on observations from the Radar Composite Chart (Echo Top Height), at around 15:30 near the accident site, it is most likely that there were cumulus-like clouds with a cloud top height between 5 km (16,000 ft) and 6 km (20,000 ft), and above these clouds, an air current disturbance was occurring.
In addition, it was possibly difficult to detect the air current disturbance visually or using the onboard weather radar.
(3) Injuries to Cabin Crew Members
The JTSB concludes that it is highly probable that the cabin crew members (R2, L2, R3 and R4) sustained injuries due to the aircraft shaking violently in a vertical direction while they made preparations for landing that should normally be done before the cabin safety check.
Regarding the bone fracture sustained by the cabin crew member (R4), it is most likely that, due to the violent vertical shaking of the aircraft, R4's body was lifted and landed with R4's right foot twisted outwards.
(4) Change to the Planned Illumination Time for the Fasten Seat Belt Sign
The JTSB concludes that it is certain that the flight crew members believed it would be safer for the cabin crew and passengers to be seated earlier based on the latest weather information obtained on board for the flight route, therefore, they changed the planned illumination time from 15:45 (upon reaching 10,000 ft) to reaching 15:29 (upon reaching FL 200), however, they did not inform the cabin crew members of this change.
It is possible that the flight crew members did not inform the cabin crew members of the change to the planned illumination time, because they were dealing with a sick passenger as well as carrying out their usual duties prior to descent.
It is important for flight crew members to be sure to promptly inform cabin crew members of the changes to the planned illumination time, by means of mutual confirmation, so that cabin crew members can make planned preparations for landing.
Japan's Ministry of Transport reported one flight attendant received a fracture of the lower right thigh, 3 others received sprains. The JTSB is investigating the occurrence.
On Apr 4th 2024 the JTSB reported the aircraft became unstable while descending through 5200 meters about 150km southeast of Narita Airport. One flight attendant sustained serious, three minor injuries. The JTSB opened an investigation.
On Jul 10th 2026 the JTSB released their final report concluding the probable causes of the accident were:
The JTSB concludes that it is most likely that the aircraft was shaken by disturbances caused by the convective activity from cumulus clouds, which resulted in the cabin crew member (R4), who was working in the aft galley, being lifted into the air in an unsteady posture and losing balance on landing, which caused serious injury.
The cabin crew member (R4) was working in the aft galley when the aircraft encountered turbulence. It most likely contributed to this that the flight crew members did not inform the cabin crew members of the change to the planned time for the fasten seat belt sign.
The JTSB analysed:
(1) Aircraft's Shaking
The JTSB concludes that, according to the EAFR records, the aircraft was more likely to have shaken significantly during its descent near FL 170 between 15:29:55 and 15:29:57.
(2) Weather Conditions
The JTSB concludes that, based on observations from the Radar Composite Chart (Echo Top Height), at around 15:30 near the accident site, it is most likely that there were cumulus-like clouds with a cloud top height between 5 km (16,000 ft) and 6 km (20,000 ft), and above these clouds, an air current disturbance was occurring.
In addition, it was possibly difficult to detect the air current disturbance visually or using the onboard weather radar.
(3) Injuries to Cabin Crew Members
The JTSB concludes that it is highly probable that the cabin crew members (R2, L2, R3 and R4) sustained injuries due to the aircraft shaking violently in a vertical direction while they made preparations for landing that should normally be done before the cabin safety check.
Regarding the bone fracture sustained by the cabin crew member (R4), it is most likely that, due to the violent vertical shaking of the aircraft, R4's body was lifted and landed with R4's right foot twisted outwards.
(4) Change to the Planned Illumination Time for the Fasten Seat Belt Sign
The JTSB concludes that it is certain that the flight crew members believed it would be safer for the cabin crew and passengers to be seated earlier based on the latest weather information obtained on board for the flight route, therefore, they changed the planned illumination time from 15:45 (upon reaching 10,000 ft) to reaching 15:29 (upon reaching FL 200), however, they did not inform the cabin crew members of this change.
It is possible that the flight crew members did not inform the cabin crew members of the change to the planned illumination time, because they were dealing with a sick passenger as well as carrying out their usual duties prior to descent.
It is important for flight crew members to be sure to promptly inform cabin crew members of the changes to the planned illumination time, by means of mutual confirmation, so that cabin crew members can make planned preparations for landing.
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