Boeing 747-422 accident near Tangshan, Cn, July 29, 2011
On July 29, 2011 at about 5:58 am local time, a Boeing 747-422, registered N173UA, was involved in an accident during enroute (climb to cruise) near Tangshan. It was flown under scheduled airline rules (Part 121). 1 person was seriously injured and 4 people had minor injuries; 381 others were unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
an inadvertent encounter with convectively induced turbulence likely due to radar limitations and convective weather developing upwards into the flight path.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 29, 2011 · about 5:58 am local time
- Place
- Tangshan, China · map
- Type
- Accident
- Injuries
- 1 person was seriously injured and 4 people had minor injuries; 381 others were unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 747-422 · all 747-422s on the register
- Registration
- N173UA · no longer on the register · serial 24380
- Damage
- Not recorded
- Flight
- Flight · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
The flight crew reported a normal takeoff and climbout with a small amount of clouds and rain in the area. The preflight weather briefing package included a forecast of convective activity including a SIGMET (significant meteorological information) for thunderstorms south of the Beijing area moving northeastward. The crew was aware of the potential for convective activity during the climbout from Beijing, and the initial enroute segment over the Bohai Sea. During flight, the Captain was actively using the airborne weather radar to search for convective returns, including using the Doppler functions. Satellite imagery showed a signature termed “transverse banding” which is indicative of thunderstorms and turbulence at altitude. Based on the lack of weather radar returns, the Captain kept the cabin seat belt sign illuminated, but advised the cabin crew that they could begin service. The airplane encountered convectively induced turbulence, resulting in a peak vertical acceleration of over 2 G’s. The activity was likely developing upwards into the flight path, and precipitation attenuation and/or radar over-scanning may have contributed to the lack of visibility of the condition, which led to the risk assessment to allow the flight attendants to begin service. Following the turbulence encounter, the flight crew controlled the airplane appropriately to avoid an overspeed or other hazardous condition. The flight and cabin crew consulted with a physician passenger and determined continuing the flight per the injured flight attendant’s desire, was appropriate.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Turbulence encounter during enroute (climb to cruise) defining event
The NTSB's findings
- cause Environmental issues › Conditions/weather/phenomena › Turbulence › Convective turbulence › Awareness of condition
Crew member
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 18,500 hours in all; 7,600 in this make and model
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Seats: 495
- Landing gear: retractable
- Engine 1: P&W PW4000 SER (turbofan); 0 hours total
- Engine 2: P&W PW4000 SER (turbofan); 0 hours total
- Engine 3: P&W PW4000 SER (turbofan); 0 hours total
- Engine 4: P&W PW4000 SER (turbofan); 0 hours total
- Operator: United Airlines
The flight
- Departed from: PEK Beijing
- Destination: KSFO San Francisco CA
- Flight plan: IFR
- A second pilot was aboard
Weather at the time
- Light: daylight
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Cabi | 1 | 4 | 10 | |
| Flight crew | 4 | |||
| LapC | 1 | |||
| Passengers | 366 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N173UA the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.