# NTSB DCA23LA304: Airbus Industrie A320-232, N479UA, Houston, TX, June 1, 2023 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 4 · Limited · Final report - Date: June 1, 2023, 16:32 local (21:32 UTC) - Place: Houston, TX - Coordinates: 29.9902, -95.3368 - Nearby events: https://openairdocs.org/map.md?lat=29.9902&lon=-95.3368&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, 117 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Major Investigations Division - Parties: United, FAA - NTSB case key (mKey): 192290 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA23LA304 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192290/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192290 - Page: https://openairdocs.org/ntsb/DCA23LA304 ## Probable cause An encounter with convectively-induced turbulence (CIT). ## 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; cases with it: [Airbus Industrie A320-232, 2 cases](https://openairdocs.org/ntsb-findings/03032020/cases.md?model=3930326), [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-descent: Turbulence encounter](https://openairdocs.org/ntsb-events/360) (defining event); cases with it: [Airbus Industrie A320-232, 3 cases](https://openairdocs.org/ntsb-events/360/sequence.md?model=3930326), [All aircraft, 423 cases](https://openairdocs.org/ntsb-events/360/sequence.md) ## Analysis A flight attendant was seriously injured when United Airlines flight 1288 encountered low-topped convectively-induced turbulence during a descent into the George Bush Intercontinental Houston Airport (IAH), Houston, Texas. Flight 1288 originated from Baltimore/Washington International Thurgood Marshall Airport (BWI), Baltimore, Maryland. The captain was the pilot monitoring, and the first officer was the pilot flying. The flight crewmembers reported that during preflight planning, the weather briefing and dispatch-provided flight papers were normal, with no turbulence concerns or convective weather issues noted. The captain briefed the flight attendants that the ride was expected to be good, and normal inflight service could be expected. During the flight, the flight crewmembers observed some weather building up along their route along the Kentucky-Tennessee border. To avoid this weather, they planned a different route, consulted with their dispatcher, and received a new route south of the building storms. As the flight was approaching the Houston terminal area, the flight crew briefed the descent and anticipated approach into IAH including a review of the weather. They indicated there were no pilot reports (PIREPS), significant meteorological information (SIGMETS), or other warnings issued for the area approaching IAH. After starting the descent, they turned the seatbelt sign on at 18,000 feet and advised the passengers via the passenger announcement (PA) system to remain seated for the rest of the flight. The flight crewmembers reported that they were in visual flight rules (VFR) conditions for the descent with a scattered cumulus layer below them around 10,000 - 13,000 feet mean sea level (MSL). No buildups were towering over them and the visibility above the scattered cumulus layer below them was good. They hadn’t received any reports of turbulence and fully expected their descent to be normal. At this time, they had not yet given the final double bell signal (indicating that the flight was approaching 10,000 feet) to the flight attendants. Just as they entered the cumulus area around 13,000 MSL it became apparent they were going to go directly through one of the cumulus clouds. Entering the cloud layer, the flight encountered brief turbulence. The flight crew classified the turbulence as being moderate and indicated that it only lasted for a few seconds. When the turbulence was encountered, two flight attendants in the aft galley, who were preparing to begin their initial descent procedures, were knocked to the floor. As one FA propped herself up into a seated position so she could get up and take her jump seat, a second encounter with turbulence occurred and she was tossed into the air. She landed directly on her tailbone, injuring her spine, and resulting in severe pain in her lower back. Shortly thereafter, the captain made a PA for the flight attendants to take their Jump seats. He did not use the phrase, “flight attendants be seatedimmediately,” because the event was over before he could grab the PA to make that announcement. Approaching 10,000 feet, the flight crew received a call from the cabin advising them that two of the flight attendants might have been injured. Passing through 10,000 feet, the captain rang the double chime and heard the purser make a passenger announcement that the flight attendants would remain seated for the rest of the flight and asked the passengers to stow all items and return their seats to the upright positions. Shortly thereafter, the flight crew received another call from the cabin advising them that one of the Flight Attendants' injuries was more severe and may require paramedics to meet the flight at the gate. Emergency medical personnel met the airplane at the gate and treated the injured flight attendant. A post-flight medical evaluation revealed that the flight attendant was diagnosed with a “spinal compression fracture.” Based on a review of weather radar (KHGX), satellite (GOES-16), and upper air model data (HRRR), the turbulence encounter was generally coincident in time and location with low-topped convective activity that reached heights above 12,000 feet. Based on the Automatic dependent surveillance-broadcast (ADS-B) data at the time of the accident, the aircraft did not look to be inside a convective updraft but was operating close to the updrafts. There was no other source of turbulence (e.g., clear-air turbulence, mountain wave turbulence) present. ## Aircraft - Registration: [N479UA](https://openairdocs.org/aircraft/N479UA), registered now, S/N 1538, built 2001 (OpenAirDocs) - Reported make and model: AIRBUS INDUSTRIE A320-232 - Registry model: [Airbus Industrie A320-232](https://openairdocs.org/model/airbus-industrie-a320-232) (registry code 3930326) (OpenAirDocs) - Registry engine: [IAE V2500SERIES](https://openairdocs.org/engine/iae-v2500series) (registry code 34601, turbo-jet) (OpenAirDocs) - Category: Airplane - Serial number: 1538 - Year built: 2001 - Engines: IAE V2500SERIES 25000 lbs thrust turbo fan; IAE V2500SERIES 25000 lbs thrust turbo fan - Damage: No damage - Flight: Part 121 - Operator: United Airlines Inc - Registered owner: United Airlines Inc - Airworthiness certificate: Standard, Commuter; Standard, Transport; Standard, Normal - Departed: KBWI, Baltimore, MD - Destination: KIAH, Houston, TX - Flight plan: IFR - Equipment: Auto-pilot, Data recorder, Electronic flight bag or handheld device, Electronic multifunction display, Electronic primary flight display, Onboard weather, Satellite tracking device, Stall warning system, Angle of attack indicator, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 59; injuries: none; flight instructor, airline transport, flight engineer; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; seat: left; restraint: 5-point; flight hours: 20,699 total, 14,616 in this make and model, 7,791 as pilot in command, 171 in the last 90 days, 69 in the last 30 days, 3 in the last 24 hours - Pilot; age 41; injuries: none; flight instructor, airline transport, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; seat: right; restraint: 5-point; flight hours: 9,614 total, 2,449 in this make and model, 1,567 as pilot in command, 145 in the last 90 days, 6 in the last 30 days ## Weather - Conditions: Instrument (IMC), Day - Wind: 180° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: 10,000 ft broken - Temperature: 88 °F, dew point 66 °F - Altimeter: 29.87 inHg - Observed at: KIAH ## Docket (4 files) The files NTSB released with the investigation on November 15, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192290. 18.2 MB in all. - Flight crew statements (item 1, PDF, 3 pages, 125 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15797649&FileExtension=pdf&FileName=Flight%20Crew%20Statements-Rel.pdf - Cabin crew statements (item 2, PDF, 3 pages, 59 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16097768&FileExtension=pdf&FileName=FA%20Statements-Rel.pdf - ADS-B data (item 3, CSV, 16.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16099004&FileExtension=csv&FileName=ADS-B%20-%20UAL1288-Rel.csv - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 4, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16141447&FileExtension=pdf&FileName=6120_Redacted-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. --- 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.