# NTSB DCA16CA220: Boeing 767 322, N657UA, International Waters, A1, August 31, 2016 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Data collection · Final report - Date: August 31, 2016, 02:10 local (02:10 UTC) - Place: International Waters, A1 - Coordinates: 46, 38.470001 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.0000&lon=38.4700&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Turbulence encounter](https://openairdocs.org/ntsb-events/360) - Highest injury: Serious injuries - Injuries: 1 serious, 11 minor - Status: Completed, report April 22, 2020 - Report: Approved by Office Director - NTSB office: Major Investigations Division - Parties: United Airlines - NTSB case key (mKey): 93972 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA16CA220 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/93972/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=93972 - Page: https://openairdocs.org/ntsb/DCA16CA220 ## Probable cause an inadvertent encounter with severe convective turbulence. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Turbulence: convective turbulence](https://openairdocs.org/ntsb-findings/03032020): Environmental issues › Conditions/weather/phenomena · Effect on personnel (probable cause); cases with it: [Boeing 767-322, 2 cases](https://openairdocs.org/ntsb-findings/03032020/cases.md?model=1385200), [All aircraft, 145 cases](https://openairdocs.org/ntsb-findings/03032020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Turbulence encounter](https://openairdocs.org/ntsb-events/360) (defining event); cases with it: [Boeing 767-322, 5 cases](https://openairdocs.org/ntsb-events/360/sequence.md?model=1385200), [All aircraft, 423 cases](https://openairdocs.org/ntsb-events/360/sequence.md) ## Analysis On August 31, 2016, at 0210 universal coordinated time, United Airlines flight 880, a Boeing 767-322, N657UA, encountered severe turbulence during cruise that resulted in one flight attendant sustaining a serious injury. Another flight attendant and 10 passengers, including one infant, received minor injuries. There were no injuries to the other passengers and crew onboard and the airplane was not damaged. The flight was operating under the provisions of 14 Code of Federal Regulations Part 121 as a regularly scheduled passenger flight from the George Bush Intercontinental Airport (KIAH), Houston, Texas to the London-Heathrow Airport (EGLL), United Kingdom. The flight diverted to the Shannon Airport (EINN), Shannon, Ireland . According to flight crew statements, the aircraft was in cruise at flight level (FL) 340 approximately 50 miles east of 40W on the North Atlantic Track X, when it encountered unexpected severe turbulence that lasted for approximately 45 seconds. The captain indicated there was forecast turbulence for this portion of the flight and there were no pilot weather reports (PIREP) or air traffic control advisories in the pre-flight weather package. The flight crew indicated that the flight conditions were smooth and devoid of any turbulence for approximately two hours prior to the event. The seat belt sign had been off for about 2 hours prior to the event. They indicated that the onboard weather radar was operating in the AUTO mode and there were no returns observed prior to the event. After the event, the seat belt sign was immediately illuminated. After assessing the level and number of injuries, the captain decided to divert to EINN to expedite After landing, all injured passengers and one flight attendant were treated for minor injuries and released; one flight attendant was admitted to the hospital with fractures of the left wrist and L3 vertebra. According to a weather analysis conducted by United Airlines, satellite imagery indicated convective buildup/enhancement in the form of an isolated cell in the region of the event. The Atlantic High Weather Prognostic Chart valid for the period depicted the potential for isolated cumulonimbus clouds over the area, which implied the potential for severe or greater turbulence associated with the convection. The nighttime conditions and lack of lightning in the lower convection, likely did not provide any visual indication of the developing storms below the flight path. Wind and temperature patterns depicted a diffluent wind flow pattern ahead of a trough over the area of the upset, which supported the development of the isolated convection. RPM Turbulence did not indicate presence of Clear Air Turbulence. ## Factual narrative On August 31, 2016, at 0210 universal coordinated time, United Airlines flight 880, a Boeing 767-322, N657UA, encountered severe turbulence during cruise that resulted in one flight attendant sustaining a serious injury. Another flight attendant and 10 passengers, including one infant, received minor injuries. There were no injuries to the other passengers and crew onboard and the airplane was not damaged. The flight was operating under the provisions of 14 Code of Federal Regulations Part 121 as a regularly scheduled passenger flight from the George Bush Intercontinental Airport (KIAH), Houston, Texas to the London-Heathrow Airport (EGLL), United Kingdom. The flight diverted to the Shannon Airport (EINN), Shannon, Ireland . According to flight crew statements, the aircraft was in cruise at flight level (FL) 340 approximately 50 miles east of 40W on the North Atlantic Track X, when it encountered unexpected severe turbulence that lasted for approximately 45 seconds. The captain indicated there was forecast turbulence for this portion of the flight and there were no pilot weather reports (PIREP) or air traffic control advisories in the pre-flight weather package. The flight crew indicated that the flight conditions were smooth and devoid of any turbulence for approximately two hours prior to the event. The seat belt sign had been off for about 2 hours prior to the event. They indicated that the onboard weather radar was operating in the AUTO mode and there were no returns observed prior to the event. After the event, the seat belt sign was immediately illuminated. After assessing the level and number of injuries, the captain decided to divert to EINN to expedite After landing, all injured passengers and one flight attendant were treated for minor injuries and released; one flight attendant was admitted to the hospital with fractures of the left wrist and L3 vertebra. According to a weather analysis conducted by United Airlines, satellite imagery indicated convective buildup/enhancement in the form of an isolated cell in the region of the event. The Atlantic High Weather Prognostic Chart valid for the period depicted the potential for isolated cumulonimbus clouds over the area, which implied the potential for severe or greater turbulence associated with the convection. The nighttime conditions and lack of lightning in the lower convection, likely did not provide any visual indication of the developing storms below the flight path. Wind and temperature patterns depicted a diffluent wind flow pattern ahead of a trough over the area of the upset, which supported the development of the isolated convection. RPM Turbulence did not indicate presence of Clear Air Turbulence. ## Aircraft - Registration: [N657UA](https://openairdocs.org/aircraft/N657UA), registered now, S/N 27112, built 1993 (OpenAirDocs) - Reported make and model: BOEING 767 322 (322) - Registry model: [Boeing 767-322](https://openairdocs.org/model/boeing-767-322) (registry code 1385200) (OpenAirDocs) - Registry engine: [Pratt & Whitney PW4000 series](https://openairdocs.org/engine/pratt-whitney-pw4000-series) (registry code 52119, turbo-fan) (OpenAirDocs) - Category: Airplane - Serial number: 27112 - Year built: 1993 - Engines: P&W PW4000 SER 24900 horsepower turbo fan; P&W PW4000 SER 24900 horsepower turbo fan - Damage: No damage - Flight: Part 121 - Operator: United Airlines - Registered owner: Wells Fargo Bank Northwest Na Trustee - Airworthiness certificate: Standard, Transport - Departed: KIAH, Houston, TX - Destination: EGLL, London - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; injuries: none; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; seat: left; restraint: 5-point; flight hours: 8,928 total, 1,765 in this make and model - Co-pilot; age 37; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; seat: right; restraint: 5-point; flight hours: 11,294 total, 3,204 in this make and model ## Weather - Conditions: Visual (VMC), Night - Turbulence: Severe ## Other investigations on N657UA (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB ENG19WA024](https://openairdocs.org/ntsb/ENG19WA024), Apr 29, 2019: Boeing 767 (N657UA), London, United Kingdom, incident, minor damage ## Docket (6 files) The files NTSB released with the investigation on May 8, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=93972. 15.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40483557&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Weather Study by United Airlines (item 2, .PDF, 600 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40483558&FileExtension=.PDF&FileName=Weather%20Study%20by%20United%20Airlines-Master.PDF - Pilot's Statement (item 3, .PDF, 307 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40483559&FileExtension=.PDF&FileName=Pilot%27s%20Statement-Master.PDF - Party Form (item 4, .PDF, 72 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40483560&FileExtension=.PDF&FileName=Party%20Form-Master.PDF - Flight Data Recorder - Specialist’s Factual Report (item 5, .PDF, 2.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40483561&FileExtension=.PDF&FileName=Flight%20Data%20Recorder%20-%20Specialist%E2%80%99s%20Factual%20Report%20-Master.PDF - Flight Data Recorder - Attachment 1 (FDR tabular data for event flight) (item 6, ZIP, 9.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40483562&FileExtension=zip&FileName=Flight%20Data%20Recorder%20-%20Attachment%201%20(FDR%20tabular%20data%20for%20event%20flight)-Master From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.