- Date
- December 3, 2024, 22:30 local (22:30 UTC)
- Place
- Pacific Ocean, Hong Kong SAR China · International waters
- Injuries
- 1 serious, 235 uninjured
- Damage
- No damage
- Phase of flight
- Enroute
- Aircraft
- N29975Boeing 787-9
- Defining event
- Enroute-descent: Turbulence encounter
- Weather
- Instrument (IMC) · Day
- Status
- Completed
- Report
- Approved by Office Director
- Investigation class
- Class 4 - Basic report with no Prelim publish
- NTSB office
- Major Investigations Division
- Parties
- United Airlines, Boeing, FAA
- Case key
- 199406
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
An encounter with unexpected turbulence during descent.
Findings · 2
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
United Airlines flight 152 encountered moderate turbulence while descending through 10,000 feet to Hong Kong International Airport. As a result, a flight attendant (FA) sustained a serious injury. During the descent, the seatbelt sign was illuminated, and the flight crew had instructed the flight attendants to prepare for landing. The aircraft passed through a thin cloud layer at approximately 10,000 feet, followed by another cloud directly ahead. No radar returns were observed on the aircraft’s weather radar display and onboard weather applications showed no indications of an adverse ride. While passing through the top of the second cloud, the aircraft experienced about two seconds of moderate turbulence. The flight continued without further incident and landed uneventfully. After taxiing to the gate, the crew was informed that the number 4 FA was injured. At the time of the turbulence encounter, the number 4 FA was in the aft galley and was thrown to the floor, impacting her head, wrist, and buttocks. MedAire was consulted, and the FA was advised to seek medical evaluation upon arrival at the hotel. She was later transported to a local hospital, where she was diagnosed with a serious injury. At the time of the turbulence encounter, there were no active forecasts indicating turbulence in the area.
Aircraft
- Registration
- N29975
- Reported as
- Boeing 787-9
- Category
- Airplane
- Serial number
- 66134
- Built
- 2020
- Airframe hours
- 11,522.55
- Engines
- GE GENX-1B, 78,500 lbs thrust, turbo fanGE GENX-1B, 78,500 lbs thrust, turbo fan
- Damage
- No damage
- Flight
- Part 121
- Operator
- United Airlines Inc
- Registered owner
- United Airlines Inc
- Airworthiness certificate
- Standard, Transport
- Last inspection
- Continuous airworthiness · December 11, 2022
- Departed
- LAX · Los Angeles, CA
- Destination
- VHHH · Hong Kong, PO
- Flight plan
- IFR
- Equipment
- ADS-B, Angle of attack indicator, Auto-pilot, Data recorder, Electronic flight bag or handheld device, Electronic multifunction display, Electronic primary flight display, Heads up display, Onboard weather, Satellite tracking device, Stall warning system
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew · 4
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 62
- Injuries
- None
- Certificate
- Airline transport
- Airplane ratings
- Single-engine land, Multi-engine sea
- Instrument ratings
- Airplane
- Medical
- Class 1, Without waivers/limitations
- Last flight review
- May 30, 2024
- Seat
- Left
- Flight hours
- 22,000 total · 5,500 in this make and model · 9,300 as pilot in command · 240 in the last 90 days · 89 in the last 30 days · 15 in the last 24 hours
- Role
- Co-pilot
- Age
- 59
- Injuries
- None
- Certificate
- Airline transport
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, With waivers/limitations
- Last flight review
- June 26, 2024
- Seat
- Right
- Flight hours
- 18,000 total · 700 in this make and model · 2,000 as pilot in command · 170 in the last 90 days · 90 in the last 30 days · 15 in the last 24 hours
- Role
- Other flight crew
- Injuries
- None
- Certificate
- Airline transport
- Seat
- Rear
- Flight hours
- 13,500 total
- Role
- Other flight crew
- Certificate
- Airline transport
- Seat
- Rear
- Flight hours
- 15,948 total
Weather
- Conditions
- Instrument (IMC) · Day
Docket · 6
The files NTSB released with the investigation on September 3, 2025, on NTSB’s docket system: statements, records, photos and specialists’ reports. 6.0 MB in all.