# NTSB DCA23LA445: Boeing 737-9, N37531, Hebron, KY, September 7, 2023

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Class 4 · Limited · Final report
- Date: September 7, 2023, 02:32 UTC
- Place: Hebron, KY
- Coordinates: 38.7509, -85.2676
- Nearby events: https://openairdocs.org/map.md?lat=38.7509&lon=-85.2676&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute-descent: Turbulence encounter](https://openairdocs.org/ntsb-events/360)
- Highest injury: Serious injuries
- Injuries: 1 serious, 70 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 4 - Basic report with no Prelim publish
- NTSB office: Major Investigations Division
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 193031
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA23LA445
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/193031/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=193031
- Page: https://openairdocs.org/ntsb/DCA23LA445

## Probable cause

An inadvertent encounter with convectively induced turbulence (CIT) during descent.

## 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 737-9, 1 case](https://openairdocs.org/ntsb-findings/03032020/cases.md?model=138470A), [All aircraft, 145 cases](https://openairdocs.org/ntsb-findings/03032020/cases.md)
- [Turbulence: convective turbulence](https://openairdocs.org/ntsb-findings/03032020): Environmental issues › Conditions/weather/phenomena · Awareness of condition; cases with it: [Boeing 737-9, 1 case](https://openairdocs.org/ntsb-findings/03032020/cases.md?model=138470A), [All aircraft, 145 cases](https://openairdocs.org/ntsb-findings/03032020/cases.md)
- [Knowledge: knowledge of meteorologic cond](https://openairdocs.org/ntsb-findings/02032020): Personnel issues › Experience/knowledge · Flight crew; cases with it: [Boeing 737-9, 1 case](https://openairdocs.org/ntsb-findings/02032020/cases.md?model=138470A), [All aircraft, 30 cases](https://openairdocs.org/ntsb-findings/02032020/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Enroute-descent: Turbulence encounter](https://openairdocs.org/ntsb-events/360) (defining event); cases with it: [Boeing 737-9, 2 cases](https://openairdocs.org/ntsb-events/360/sequence.md?model=138470A), [All aircraft, 423 cases](https://openairdocs.org/ntsb-events/360/sequence.md)

## Analysis

United Airlines flight 1759 encountered moderate turbulence while descending through 11,000 ft for landing at Cincinnati/Northern Kentucky International Airport (CVG) Hebron, Kentucky, and a flight attendant (FA) fractured her pelvis. The flight crew reported that while descending on the SARGO-3 arrival into CVG they observed a single cloud with no apparent vertical development at about 11,000 ft. With no indication of an adverse ride from air traffic control (ATC), their onboard weather applications or their weather radar, the pilots elected to continue. Upon entering the cloud, the flight encountered about 2 seconds of moderate turbulence. Following the turbulence encounter the flight crew received a call from the cabin advising them that a FA had been injured. The aft FA assigned to jumpseat 2L reported that she was completing her duties in the aft galley and was seated in her jumpseat but had not fastened her safety harness, when suddenly and without warning, they encountered severe turbulence. She was thrown into the air, struck the ceiling and impacted the floor on her side fracturing her pelvis. Upon being notified of the injury, the flight crew declared a medical emergency and requested paramedics meet the aircraft at the gate. The injured FA was transported to the hospital where she was diagnosed with a fractured pelvis. At the time of the turbulence encounter there were no active significant meteorological information (SIGMETs), convective SIGMETs, airman’s meteorological information (AIRMETs), or pilot reports (PIREPs) of any significant turbulence.

## Aircraft

- Registration: [N37531](https://openairdocs.org/aircraft/N37531), registered now, S/N 66119, built 2022 (OpenAirDocs)
- Reported make and model: BOEING 737-9
- Registry model: [Boeing 737-9](https://openairdocs.org/model/boeing-737-9) (registry code 138469A) (OpenAirDocs)
- Registry engine: [CFM International LEAP-1B28B series](https://openairdocs.org/engine/cfm-international-leap-1b28b-series) (registry code 13124, turbo-fan) (OpenAirDocs)
- Category: Airplane
- Serial number: 66119
- Year built: 2022
- Engines: CFM INTL LEAP-1B-28G06 27900 lbs thrust turbo fan; CFM INTL LEAP-1B-28G06 27900 lbs thrust turbo fan
- Damage: No damage
- Flight: Part 121
- Operator: United Airlines Inc
- Registered owner: United Airlines Inc
- Airworthiness certificate: Standard, Transport
- Departed: Houston, TX
- Destination: Cinncinati, OH
- Flight plan: IFR
- Equipment: Onboard weather, Heads up display, Electronic primary flight display, Electronic multifunction display, Auto-pilot, Electronic flight bag or handheld device, Stall warning system, ADS-B, Data recorder

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; injuries: none; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review February 6, 2023; seat: left; restraint: 4-point; flight hours: 11,000 total, 3,400 in this make and model, 2,500 as pilot in command, 200 in the last 90 days, 50 in the last 30 days
- Co-pilot; age 48; injuries: none; flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review April 26, 2023; seat: right; restraint: 4-point; flight hours: 15,700 total, 10,500 in this make and model, 2,000 as pilot in command, 50 in the last 90 days, 17 in the last 30 days

## Weather

- Conditions: Visual (VMC), Night
- Wind: 190° at 5 knots
- Visibility: 10 statute miles
- Temperature: 72 °F, dew point 70 °F
- Altimeter: 29.85 inHg
- Turbulence: Moderate
- Observed at: KCVG, 39 nm away
- METAR: KCVG 070252Z 19005KT 10SM FEW070 22/21 A2985 RMK AO2 SLP097 T02170206 50000

## Docket (3 files)

The files NTSB released with the investigation on March 27, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=193031. 2.2 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16194510&FileExtension=pdf&FileName=6120_1dms_Redacted-Rel.pdf
- Flight crew statements (item 2, PDF, 5 pages, 105 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16194557&FileExtension=pdf&FileName=Flight%20Crew%20Statements-Rel.pdf
- Flight attendant statements (item 3, PDF, 1 page, 79 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16194166&FileExtension=pdf&FileName=Flight%20Attendant%20Statements-Rel.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.

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