Boeing 777-223 accident near Pacific Ocean, April 11, 2011
On April 11, 2011 at about 7:00 am local time, a Boeing 777-223, registered N766AN, was involved in an accident during enroute (climb to cruise) near Pacific Ocean (Narita International Airport). It was flown under scheduled airline rules (Part 121). 2 people were seriously injured and 2 people had minor injuries; 227 others were unhurt. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
An inadvertent encounter with convective-induced turbulence upon entering cumulonimbus clouds.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 11, 2011 · about 7:00 am local time
- Place
- Pacific Ocean · Narita International Airport · map
- Type
- Accident
- Injuries
- 2 people were seriously injured and 2 people had minor injuries; 227 others were unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 777-223 · all 777-223s on the register
- Registration
- N766AN · registry record · serial 32880
- Damage
- Not recorded
- Flight
- Flight · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
As the airplane was climbing, the flight crew observed a small weather buildup in front of them. They requested a deviation around the weather, but the air traffic controller requested that they stand by. After entering the weather, they received clearance to turn; however, about 24,000 feet, the airplane encountered about 11 seconds of moderate, and then severe, turbulence. During the encounter, two flight attendants received broken ankles while conducting work in the aft cabin area. The digital flight data recorder revealed that during the encounter vertical acceleration forces went from 2.2G to 0.6913G within 1 second, to a minimum of 0.496G about 5 seconds after the 2.2G maximum. A weather study conducted by a National Transportation Safety Board meteorologist revealed a frontal wave over the Japanese coast with a warm front extending eastward in the vicinity of the turbulence encounter. A gale force wind was expected. The region of the turbulence encounter also contained low to mid-level clouds with cloud tops near 14,000 feet; cumulonimbus cloud development, with tops up to 26,000 feet, was slightly upstream from the turbulence encounter. Review of the weather package given to the flight crew found no forecasts for turbulence and no Significant Meteorological Information advisories (SIGMETS) were in effect for the route of flight. At the time of the occurrence, there were no reports of turbulence from pilots ahead of the accident flight and the flight crew saw no indication of turbulence on their weather radar.
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 › Effect on personnel
Pilot
- Certificate: airline transport pilot, flight engineer
- Ratings: multi-engine land; instrument: airplane
- Flight time: 174 in the last 90 days; 82 in the last 30 days
- Last flight review: October 26, 2010
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: left
- Injury: no injuries
Co-pilot
- Certificate: airline transport pilot, flight engineer
- Ratings: multi-engine land; instrument: airplane
- Flight time: 47 in the last 90 days; 47 in the last 30 days
- Last flight review: February 15, 2011
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: unk
- Injury: no injuries
Co-pilot
- Certificate: airline transport pilot, flight engineer
- Ratings: multi-engine land; instrument: airplane
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: unk
- Injury: no injuries
The aircraft
- Airframe total time: 33,558 hours
- Last inspection: continuous airworthiness programme
- Maximum gross weight: 648,000 lb
- Seats: 263
- Landing gear: retractable
- Engine: Rolls Royce Trent 892 (turbofan); 0 hours total
- Operator: American Airlines INC
The flight
- Departed from: NRT Narita at 6:25 am
- Destination: LAX Los Angeles CA
- Flight plan: IFR
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 245° at 65 knots
- Visibility: 25 statute miles
- Sky: broken clouds; a few clouds at 3,000 ft
- Temperature: -36°F (-38°C), dew point 0°F (-18°C)
- Observation at 6:30 am from NRT, 194 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Cabi | 2 | 2 | 8 | |
| Flig | 3 | |||
| Passengers | 216 |
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 N766AN the same tail number, which may have belonged to a different aircraft at the time
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number WPR11LA203.