Boeing 777 accident near Southern Tip Of Greenland, Dk, May 25, 2010
On May 25, 2010 at about 1:05 pm local time, a Boeing 777, registered N794UA, was involved in an accident during enroute (cruise) near Southern Tip Of Greenland. It was flown under scheduled airline rules (Part 121). 2 people were seriously injured; 209 others were unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
An inadvertent encounter with unforecast turbulence in cruise flight.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 25, 2010 · about 1:05 pm local time
- Place
- Southern Tip Of Greenland, Denmark · map
- Type
- Accident
- Injuries
- 2 people were seriously injured; 209 others were unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 777 200B · all 777s on the register
- Registration
- N794UA · registry record
- Damage
- Not recorded
- Flight
- Flight · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
The flight encountered clear air turbulence near the southern tip of Greenland. A review of the weather briefing provided to the accident flight crew by company Flight Dispatch contained relevant SIGMETs along the proposed route of flight. The package was not found to be missing any pertinent published information that could have alerted the flight crew to an enroute encounter with turbulence over Greenland. Analysis of the calculated winds indicated the airplane encountered a downdraft on the order of 13 feet/sec followed sharply by an updraft of approximately 24 feet/sec. Simulation analysis of the upset confirmed that the airplane reacted as expected to the calculated wind profile and the recorded control inputs. Based on the simulation study that was performed, the recorded elevator input from the autopilot during the disturbance reduced the magnitude of the upset. Analysis of the surrounding atmosphere and GOES-3 satellite photographs indicated the presence of icecap wave instability along the airplane's route of flight that was capable of producing rapidly changing vertical winds on the order of 20 feet per second, which resulted in conditions conducive to severe turbulence.
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 (cruise) defining event
The NTSB's findings
- cause Environmental issues › Conditions/weather/phenomena › Turbulence › Clear air turbulence › Awareness of condition
The aircraft
- Landing gear: retractable
- Operator: United Airlines, Inc.
The flight
- Departed from: LHR London at 9:29 am
- Destination: LAX Los Angeles 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 | 11 | ||
| Flight crew | 3 | |||
| Passengers | 1 | 195 |
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.
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.