# NTSB DCA16CA181: Boeing 737 724, N23708, Port Arthur, TX, March 15, 2016

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Data collection · Final report
- Date: March 14, 2016, 21:56 local (Mar 15, 2016, 02:56 UTC)
- Place: Port Arthur, TX
- Coordinates: 29.686666, -94.038055 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=29.6867&lon=-94.0381&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute-cruise: Clear air turbulence encounter](https://openairdocs.org/ntsb-events/362)
- Highest injury: Serious injuries
- Injuries: 1 serious, 133 uninjured
- Status: Completed, report April 22, 2020
- Report: Approved by Office Director
- NTSB office: Major Investigations Division
- Parties: United Airlines
- NTSB case key (mKey): 93343
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA16CA181
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/93343/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=93343
- Page: https://openairdocs.org/ntsb/DCA16CA181

## Probable cause

an inadvertent encounter with clear air turbulence.

## 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 737-724, 1 case](https://openairdocs.org/ntsb-findings/03032015/cases.md?model=13844BY), [All aircraft, 78 cases](https://openairdocs.org/ntsb-findings/03032015/cases.md)

## Sequence of events

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

- [Enroute-cruise: Clear air turbulence encounter](https://openairdocs.org/ntsb-events/362) (defining event); cases with it: [Boeing 737-724, 1 case](https://openairdocs.org/ntsb-events/362/sequence.md?model=13844BY), [All aircraft, 24 cases](https://openairdocs.org/ntsb-events/362/sequence.md)

## Analysis

On March 14, 2016, 2156 central daylight time, United Airlines flight 898,a Boeing 737-724, N23708, encountered turbulence during cruise that resulted in one flight attendant sustaining a serious injury near Port Arthur, Texas. There were no injuries to the other passengers and crew aboard 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 (IAH), Houston, Texas to the Louis Armstrong New Orleans International Airport (MSY), New Orleans, Louisiana. According to flight crew statements, the captain was the flying pilot and the first officer (FO) was the pilot monitoring. The airplane was level at flight level (FL) 270, with the autopilot off, in clear air with no convective activity in the vicinity. Immediately before before beginning the descent into IAH, the flight encountered a momentary pocket of moderate to severe turbulence with the airplane banking approximately 25 – 30 degrees to the right, and the altitude fluctuating from 100 feet up to 60 - 160 feet down. The flight crew did not recall seeing anything on the onboard weather radar or TCAS (traffic collision avoidance system). The captain immediately turned on the seat belt sign and made an announcement on the public address for the passengers to fasten their seat belts. Shortly after, the flight crew were informed that a flight attendant FA was injured. The captain called the cabin and was informed that one of the FAs was severely injured. The flight crew declared a medical emergency and arranged for paramedics to meet the flight at the gate. The FA was transported to a local hospital and diagnosed with serious injuries. According to a weather analysis conducted by United Airlines, satellite imagery indicated no significant cloud features over the route of flight, with the moisture channel imagery indicating moisture channel darkening or drier air in the middle tropospheric levels across the northern half of Texas and southern Los Angeles with increasing moisture further to the south with the stronger jet stream winds. A review of pilot reports (PIREPs) across the region leading up to the turbulence only indicated light turbulence being encountered. Consequently, The Weather Company forecasts only called for light turbulence for the route. However, several Aircraft Meteorological Data and Reporting (AMDAR) automated reports across the region indicated that winds were stronger than predicted at higher levels and indicated a strong vertical wind shear at higher levels than originally forecast.

## Factual narrative

On March 14, 2016, 2156 central daylight time, United Airlines flight 898,a Boeing 737-724, N23708, encountered turbulence during cruise that resulted in one flight attendant sustaining a serious injury near Port Arthur, Texas. There were no injuries to the other passengers and crew aboard 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 (IAH), Houston, Texas to the Louis Armstrong New Orleans International Airport (MSY), New Orleans, Louisiana. According to flight crew statements, the captain was the flying pilot and the first officer (FO) was the pilot monitoring. The airplane was level at flight level (FL) 270, with the autopilot off, in clear air with no convective activity in the vicinity. Immediately before before beginning the descent into IAH, the flight encountered a momentary pocket of moderate to severe turbulence with the airplane banking approximately 25 – 30 degrees to the right, and the altitude fluctuating from 100 feet up to 60 - 160 feet down. The flight crew did not recall seeing anything on the onboard weather radar or TCAS (traffic collision avoidance system). The captain immediately turned on the seat belt sign and made an announcement on the public address for the passengers to fasten their seat belts. Shortly after, the flight crew were informed that a flight attendant FA was injured. The captain called the cabin and was informed that one of the FAs was severely injured. The flight crew declared a medical emergency and arranged for paramedics to meet the flight at the gate. The FA was transported to a local hospital and diagnosed with serious injuries. According to a weather analysis conducted by United Airlines, satellite imagery indicated no significant cloud features over the route of flight, with the moisture channel imagery indicating moisture channel darkening or drier air in the middle tropospheric levels across the northern half of Texas and southern Los Angeles with increasing moisture further to the south with the stronger jet stream winds. A review of pilot reports (PIREPs) across the region leading up to the turbulence only indicated light turbulence being encountered. Consequently, The Weather Company forecasts only called for light turbulence for the route. However, several Aircraft Meteorological Data and Reporting (AMDAR) automated reports across the region indicated that winds were stronger than predicted at higher levels and indicated a strong vertical wind shear at higher levels than originally forecast.

## Aircraft

- Registration: [N23708](https://openairdocs.org/aircraft/N23708), registered now, S/N 28769, built 1998 (OpenAirDocs)
- Reported make and model: BOEING 737 724 (724)
- Registry model: [Boeing 737-724](https://openairdocs.org/model/boeing-737-724) (registry code 13844BY) (OpenAirDocs)
- Registry engine: [CFM International CFM56 series](https://openairdocs.org/engine/cfm-international-cfm56-series) (registry code 13802, turbo-fan) (OpenAirDocs)
- Category: Airplane
- Serial number: 28769
- Year built: 1998
- Engines: CFM INTL. CFM56 SERIES turbo fan; CFM INTL. CFM56 SERIES turbo fan
- Damage: No damage
- Flight: Part 121
- Operator: United Airlines
- Registered owner: Wells Fargo Bank Northwest Na Trustee
- Airworthiness certificate: Standard, Transport
- Departed: IAH, HOUSTON, TX
- Destination: MSY, NEW ORLEANS, LA
- Flight plan: IFR
- Equipment: Onboard weather, Stall warning system, ADS-B, Angle of attack indicator, Auto-pilot, Data recorder, Electronic flight bag or handheld device, Electronic multifunction display, Electronic primary flight display

## 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; seat: left; restraint: 5-point; flight hours: 11,000 total, 7,000 in this make and model
- Co-pilot; age 45; injuries: none; airline transport; airplane ratings: multi-engine sea; instrument ratings: airplane; medical: class 1; seat: right; restraint: 5-point; flight hours: 5,000 in this make and model, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night
- Wind: 270° at 40 knots
- Lowest ceiling: none
- Turbulence: Severe

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 20160314003289A](https://openairdocs.org/incident/20160314003289A), Mar 14, 2016: Boeing 737-724, No damage. Untied flight 898 iah to msy reported to ATC moderate turbulence over lake charles, la at FL270. The weather was a top a cloud layer mostly clear. A short time…

## Other investigations on N23708 (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 DCA14LA060](https://openairdocs.org/ntsb/DCA14LA060), Feb 17, 2014: Boeing 737 (N23708), Kaycee, WY, no damage. Probable cause: an encounter with severe mountain wave turbulence during cruise flight.

## Docket (5 files)

The files NTSB released with the investigation on July 21, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=93343. 13.1 MB in all.

- Flight data recorder - specialista��s factual report (item 1, PDF, 10 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=5591837&FileExtension=pdf&FileName=DCA16CA181_FDR_Factual_FINAL-Rel.pdf
- Flight data recorder - attachment 1 (FDR tabular data for entire flight) (item 2, CSV, 8.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=5592271&FileExtension=csv&FileName=FINAL_DCA16CA181_Attachment1_TabData-Rel.csv
- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 3, PDF, 11 pages, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=6297158&FileExtension=pdf&FileName=FSI%202016-07%20NTSB%20Flight%20898-14Mar16%20IAHMSY%206120_1web_Reader_Redacted-Rel.pdf
- Pilot's statement (item 4, PDF, 4 pages, 32 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=6297238&FileExtension=pdf&FileName=Pilot%20Statements-Rel.pdf
- Weather reports and records (item 5, PDF, 9 pages, 450 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=6296302&FileExtension=pdf&FileName=UAL898_IAH-MSY_15Mar16%20Turbc%20Event-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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