# NTSB ERA11CA511: Boeing 737-823, N804NN, Miami, FL, September 29, 2011 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Data collection · Final report - Date: September 29, 2011, 16:27 local (20:27 UTC) - Place: Miami, FL - Coordinates: 25.766666, -80.291664 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=25.7667&lon=-80.2917&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-descent: Clear air turbulence encounter](https://openairdocs.org/ntsb-events/362) - Highest injury: Serious injuries - Injuries: 1 serious, 165 uninjured - Status: Completed, report March 8, 2012 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - NTSB case key (mKey): 81941 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA11CA511 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/81941/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=81941 - Page: https://openairdocs.org/ntsb/ERA11CA511 ## Probable cause The in-flight encounter with clear air turbulence, which resulted in an injury to a cabin attendant. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Turbulence: clear air turbulence](https://openairdocs.org/ntsb-findings/03032015): Environmental issues › Conditions/weather/phenomena · Effect on personnel (probable cause); cases with it: [Boeing 737-823, 3 cases](https://openairdocs.org/ntsb-findings/03032015/cases.md?model=13844CB), [All aircraft, 78 cases](https://openairdocs.org/ntsb-findings/03032015/cases.md) - [Impairment/incapacitation: illness/injury](https://openairdocs.org/ntsb-findings/02012010): Personnel issues › Physical · Cabin crew; cases with it: [Boeing 737-823, 2 cases](https://openairdocs.org/ntsb-findings/02012010/cases.md?model=13844CB), [All aircraft, 34 cases](https://openairdocs.org/ntsb-findings/02012010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-descent: Clear air turbulence encounter](https://openairdocs.org/ntsb-events/362) (defining event); cases with it: [Boeing 737-823, 1 case](https://openairdocs.org/ntsb-events/362/sequence.md?model=13844CB), [All aircraft, 24 cases](https://openairdocs.org/ntsb-events/362/sequence.md) ## Analysis According to crew statements, the airplane was descending through about 16,000 feet mean sea level in clear air when it encountered two jolts of turbulence that did not damage the airplane but resulted in a flight attendant being lifted off the deck and hitting the ceiling, then being thrown to the floor and breaking her ankle. The flight attendant was in the galley preparing for landing, and the seat belt sign was illuminated. The captain had previously deviated for weather, and the airplane was operating between cloud buildups at the time. The captain also noted that the air was relatively smooth, and that radar returns indicated that the airplane was more than 20 miles from any significant weather. ## Factual narrative According to crew statements, the airplane was descending through approximately 16,000 feet in clear air when it encountered two jolts that did not damage the airplane, but resulted in a flight attendant being lifted off the deck and hitting the ceiling, then being thrown to the floor and breaking her ankle. The flight attendant was in the galley preparing for landing, and the seat belt sign was illuminated. The captain had previously deviated for weather, and the airplane was operating between cloud buildups at the time. The captain also noted that the air was relatively smooth, and that radar returns indicated that the airplane was greater than 20 miles from any significant weather. ## Aircraft - Registration: [N804NN](https://openairdocs.org/aircraft/N804NN), registered now, S/N 29567 (OpenAirDocs) - Reported make and model: BOEING 737-823 - Registry model: [Boeing 737-823](https://openairdocs.org/model/boeing-737-823) (registry code 13844CB) (OpenAirDocs) - Registry engine: [CFM International CFM56-7B24/3 series](https://openairdocs.org/engine/cfm-international-cfm56-7b24-3-series) (registry code 13074, turbo-fan) (OpenAirDocs) - Category: Airplane - Serial number: 29567 - Engines: CFM INTL CFM56-7B24/3 22800 lbs thrust turbo fan; CFM INTL CFM56-7B24/3 22800 lbs thrust turbo fan - Damage: No damage - Flight: Part 121 - Operator: American Airlines Inc - Registered owner: American Airlines Inc - Airworthiness certificate: Standard, Transport - Departed: LIR, Liberia - Destination: MIA, Miami, FL - Flight plan: IFR - Airport: MIA, Miami International ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, unknown; last flight review August 11, 2010; flight hours: 6,262 total, 2,104 in this make and model ## Weather - Conditions: Visual (VMC), Day ## Docket (2 files) The files NTSB released with the investigation on January 25, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=81941. 458 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 392 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40361133&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Crew Statements (item 2, .PDF, 66 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40361134&FileExtension=.PDF&FileName=Crew%20Statements-Master.PDF 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.