# NTSB CHI00LA296: Boeing 727-224, N296SC, Minneapolis, MN, September 10, 2000 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 10, 2000, 09:38 local (14:38 UTC) - Place: Minneapolis, MN - Coordinates: 44.879234, -93.220794 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.8792&lon=-93.2208&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 101 uninjured - Status: Completed, report October 17, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 50355 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI00LA296 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/50355/pdf - Page: https://openairdocs.org/ntsb/CHI00LA296 ## Probable cause The fatigue failure of the wheel assembly. A factor was the inadequate inspection procedures prior to the issuance of a service bulletin. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, taxi - to takeoff - landing gear,wheel - fatigue (cause) - maintenance,inspection - inadequate (contributing factor) - landing gear,wheel - failure,total (cause) ## Analysis The Boeing 727-224 number 3 wheel assembly failed during taxi for takeoff and pieces of the wheel assembly impacted the airframe causing damage. Examination of the wheel assembly revealed a fatigue failure that emanated from a point at the inside diameter of one of the brake lugs. A circumferential scratch was found adjacent to the fatigue origin. The wheel half had been inspected by an approved repair station and shipped to the airline on July 21, 2000. The wheel was installed on the accident aircraft and had accumulated 356.2 hours time in service at the time of the accident. A review of repair station records revealed that the repair station had been rejecting about 4 wheel halves per month. Prior to the accident, the repair station was finding cracks on other wheel halves in the area where the wheel failure occurred. The repair station had been in contact with the wheel manufacturer concerning this matter and had sent representative wheel halves to the manufacturer for evaluation. In a conversation with a representative of the Federal Aviation Administration, the wheel manufacturer stated that one of the returned wheel halves had been examined and that a manufacturing defect had created a stress concentrator, which resulted in a fatigue failure of the wheel half. The wheel manufacturer issued a Service Bulletin to rework the lugs and to provide guidance in inspecting the affected areas of the wheel assembly. ## Factual narrative On September 10, 2000, at 0938 central daylight time, a Boeing 727-224, N296SC, operated by Sun Country Airlines as flight 791, sustained substantial damage when the number 3 wheel and tire assembly failed during taxi at the Minneapolis International Airport, Minneapolis, Minnesota. Pieces of the wheel assembly subsequently impacted the airframe causing the damage. The 14 CFR Part 121 flight was operating in visual meteorological conditions at the time of the accident. No injuries were reported to the 7 crew members or 94 passengers on board. The flight was taxiing to the runway for a departure to the San Francisco International Airport, San Francisco, California. The wheel components were sent to the NTSB Materials Laboratory in Washington, D.C. for further examination. The examination report indicates that most of the fracture surfaces exhibited signatures consistent with overstress fracture. However, a portion of the fracture surface exhibited signatures consistent with fatigue. The fatigue origin was found to emanate from a point at the inside diameter of one of the brake lugs. A circumferential scratch was found adjacent to the fatigue origin. The wheel half had been inspected by an approved repair station and shipped to the airline on July 21, 2000. The wheel had accumulated 356.2 hours time in service at the time of the accident. A review of repair station records revealed that the repair station had been rejecting about 4 wheel halves per month. Prior to the accident, the repair station was finding cracks on other wheel halves in the area where the wheel failure occurred. The repair station had been in contact with the wheel manufacturer concerning this matter and had sent representative wheel halves to the manufacturer for evaluation. In a conversation with a representative of the Federal Aviation Administration, the wheel manufacturer stated that one of the returned wheel halves had been examined and that a manufacturing defect had created a stress concentrator, which resulted in a fatigue failure of the wheel half. On May 04, 2001, the wheel manufacturer issued a Service Bulletin, number 2604561-32-001, to rework the lugs and to provide guidance in inspecting the affected areas of the wheel assembly. ## Aircraft - Registration: [N296SC](https://openairdocs.org/deregistered/N296SC-2007-09-20), registration cancelled 2007-09-20, S/N 22449, built 1981 (OpenAirDocs) - Reported make and model: Boeing 727-224 - Registry model: [Boeing 727-224](https://openairdocs.org/model/boeing-727-224) (registry code 1384076) (OpenAirDocs) - Category: Airplane - Serial number: 22449 - Engines: P&W JT8D-15 12000 lbs thrust turbo fan - Damage: Substantial damage - Flight: Part 121 - Operator: Sun Country Airlines - Registered owner: Pegasus Aviation, Inc. - Airworthiness certificate: Standard, Transport - Departed: MSP - Destination: SFO, SAN FRANCISCO, CA - Flight plan: IFR - Airport: MSP, Minneapolis St. Paul Intl ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; airline transport, commercial; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 14,265 total, 8,975 in this make and model, 12,009 as pilot in command, 191 in the last 90 days, 73 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 151 °F, dew point 113 °F - Altimeter: 29.00 inHg - Observed at: MSP ## 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 20000910007999A](https://openairdocs.org/incident/20000910007999A), Sep 10, 2000: Boeing 727224, Minneapolis, MN, No damage. (-23) Sun country airlines flight 791, during taxi for departure, experienced main landing gear number 3 wheel fracture. The wheel separated with extreme force… 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.