Created Tuesday, Apr 22nd 2025 17:51Z, last updated Friday, Oct 24th 2025 09:42Z
A United Boeing 787-9, registration N27958 performing flight
UA-1 from San Francisco,CA (USA) to Singapore (Singapore) with 174 passengers and 15 crew, was enroute at FL400 near Butuan City (Philippines) when the aircraft encountered severe turbulence causing serious injuries to two flight attendants, 3 minor injuries to other flight attendants and minor injuries to one passenger. The aircraft continued to Singapore for a safe landing about 3 hours later.
The FAA reported one flight attendant received serious injuries, 3 flight attendants and one passenger minor injuries. The occurrence was rated an accident.
The NTSB reported they joined the investigation led by Philippines CAA via an accredited representative.
On Oct 10th 2025 the NTSB reported they are now investigating the occurrence, a final report will be released by the NTSB in due time.
On Oct 24th 2025 the NTSB released their final report and investigation docket concluding the probable cause of the accident was:
An encounter with convective turbulence during cruise that was not detected in advance by cockpit weather radar or weather information services.
The NTSB analysed:
A review of weather records revealed areas of scattered convection were present to the northeast of the accident location. The flight crew reported that prior to the accident the flight was smooth, and they had been deviating around small, scattered returns noted on the cockpit weather radar as they flew southwest toward the intended destination.
The weather provider noted that there were no significant meteorological information (SIGMETs) or flight plan guidance advisories for turbulence or convective activity for the area, due to the scattered nature of the convection. Fusion satellite and lightning data showed isolated convective cells near the accident location and time, with lightning development and likely updrafts.
The flight crew reported that prior to the accident, the airplane was at flight level 400 in a thin cirrus cloud layer, there was no moonlight and the flight was smooth. The seatbelt sign was off.
Immediately before the turbulence encounter, cockpit weather radar displayed no returns ahead of the airplane at any range. There were no messages or alerts about weather from dispatch, nor any indication of weather activity from their 3rd party data sources (Skypath and WSI). The flight crew described the turbulence as a sudden and severe jolt that lasted 3-5 seconds, during which it was difficult to read the instrument panel. Immediately after the turbulence subsided, the flight was smooth.
The FAs working in the aft galley (where the serious injuries occurred) described the turbulence as sudden and brief, the airplane dropped beneath them (or they were lifted off their feet) and they fell to the floor with severe force.
The other cabin crew solicited assistance from passengers with medical experience and rendered aid to those injured. They enlisted a non-revenue FA to replace one of the injured crew, to cover one of the doors during landing.
The captain coordinated with the cabin crew, dispatch and the remote medical advisory service, and the first officer. After considering a diversion to Manila, they chose to continue to WSSS, which was about 80 minutes away. The flight crew declared an emergency, landed uneventfully, and medical personnel met the airplane at the gate. One FA sustained a broken ankle requiring surgery and another was hospitalized for longer than 48 hours with a head injury.
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