# NTSB DEN04LA019: Boeing 737-500, N956UA, Denver, CO, November 1, 2003 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: November 1, 2003, 12:15 local (19:15 UTC) - Place: Denver, CO - Coordinates: 40.491943, -105.236389 - Nearby events: https://openairdocs.org/map.md?lat=40.4919&lon=-105.2364&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor, 95 uninjured - Status: Completed, report March 30, 2004 - Report: Approved by Office Director - Parties: FAA FSDO - NTSB case key (mKey): 58285 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN04LA019 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/58285/pdf - Page: https://openairdocs.org/ntsb/DEN04LA019 ## Probable cause the in-flight encounter with heavy to moderate turbulence. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, descent - weather condition - turbulence (cause) ## Analysis During the descent at FL 240, the captain asked the cabin crew to take their seats. At FL 210, the airplane encountered heavy to moderate turbulence. One flight attendant received minor injuries and another flight attendant received serious injuries. The airplane continued to Denver without further incident. ## Factual narrative On November 1, 2003, at approximately 1215 mountain standard time, a Boeing 737-500, N956UA, operated by United Airlines as flight 1232, encountered turbulence while on approach to Denver International Airport (DEN), Denver, Colorado. The airline transport captain and airline transport first-officer, 1 flight attendant, and 92 passengers were not injured; however, 1 flight attendant was seriously injured and 1 flight attendant received minor injuries. Instrument meteorological conditions prevailed. The scheduled domestic passenger flight was being conducted under the provisions of Title 14 CFR Part 121. An instrument flight rules flight plan had been filed for the flight from Boise, Idaho, to Denver, Colorado, departed at 1045. At flight level (FL) 310, air traffic control advised the captain that light to moderate turbulence existed between FL170 and FL 200. The flight crew directed the passengers to take their seats and fasten their seatbelts. During the descent, at FL 240, the captain asked the cabin crew to take their seats. At FL 210, the flight encountered "heavy to moderate turbulence with two rapid up-down vertical-G cycles." One flight attendant received minor injuries and another flight attendant received a fractured ankle. The flight continued to Denver without further incident. ## Aircraft - Registration: [N956UA](https://openairdocs.org/deregistered/N956UA-2005-07-06), registration cancelled 2005-07-06, S/N 26704, built 1993 (OpenAirDocs) - Reported make and model: Boeing 737-500 - Registry model: [Boeing 737-522](https://openairdocs.org/model/boeing-737-522) (registry code 138449F) (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: 26704 - Airframe hours: 29534 - Engines: CFM International CFM56-3-B1 20000 lbs thrust turbo fan; CFM International CFM56-3-B1 20000 lbs thrust turbo fan - Damage: No damage - Flight: Part 121 - Operator: United Air Lines Inc - Registered owner: Wilmington Trust Company - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, February 16, 2003, 1,641 hours before - Departed: BOI, Boise, ID - Destination: DEN, Denver, CO - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; injuries: none; flight engineer, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; last flight review July 1, 2003; seat: left; flight hours: 4,751 total, 1,838 in this make and model, 246 in the last 90 days, 90 in the last 30 days, 6 in the last 24 hours - Co-pilot; age 39; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: right; flight hours: 2,655 total, 22 in this make and model, 68 in the last 90 days, 22 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 7 knots - Visibility: 4 statute miles - Lowest ceiling: 500 ft overcast - Temperature: 30 °F, dew point 30 °F - Altimeter: 29.95 inHg - Observed at: DEN ## 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 20031101027999A](https://openairdocs.org/incident/20031101027999A), Nov 1, 2003: Boeing 737522, Denver, CO. (-23) United airlines flight #1232 inbound from boise to Denver had reports from prior aircraft in area of turbulence ahead at or about FL 240. Captain… ## Other investigations on N956UA (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 LAX97IA243](https://openairdocs.org/ntsb/LAX97IA243), Jul 15, 1997: Boeing 737-522 (N956UA), Ontario, CA, incident, no damage. Probable cause: a laser light source of undetermined origin directed toward the cockpit window of an aircraft in-flight by a person or persons unknown. 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.