# NTSB FTW97LA334: Beech E90, N16NM, Albuquerque, NM, August 31, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 31, 1997, 17:40 local (23:40 UTC) - Place: Albuquerque, NM - Coordinates: 35.06047, -106.620025 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.0605&lon=-106.6200&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report May 4, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 20333 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW97LA334 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20333/pdf - Page: https://openairdocs.org/ntsb/FTW97LA334 ## Probable cause Fatigue failure of the right main landing gear retraction/extension torque tube. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Main gear collapsed, landing - roll - landing gear,normal retraction/extension assembly - fatigue (cause) - landing gear,normal retraction/extension assembly - failure,total (cause) ## Analysis During initial climb following takeoff from Santa Rosa on a medical evacuation flight, with a patient and 2 flight nurses aboard, the right main landing gear failed to fully retract. Prior to landing at Albuquerque the right main landing gear did not lock in the down position. During landing roll, the right main landing gear collapsed. Examination of the landing gear provided evidence that the retraction/extension torque tube failed in fatigue. ## Factual narrative On August 31, 1997, at 1740 mountain daylight time, a Beech E-90, N16NM, operating as a lifeguard flight from Santa Rosa, New Mexico, to Albuquerque, New Mexico, collapsed the right main landing gear during landing roll at Albuquerque. The airline transport pilot, 2 flight nurses, and the patient were not injured and the aircraft sustained substantial damage. Visual meteorological conditions prevailed and an IFR flight plan was filed for this Title 14 CFR Part 135 medical flight which departed Santa Rosa, New Mexico, at 1634. According to the pilot, when the landing gear was raised after departure, he heard a grinding noise emitting from under the cabin floor and noted that the "gear in transit" light in the landing gear handle remained illuminated. The pilot said he pulled the landing gear motor circuit breaker and the noise stopped. He then attempted to recycle the gear with negative results. When the landing gear was lowered on arrival at Albuquerque, an unsafe right main landing gear indication was present. The pilot secured the right engine, feathered the right propeller, and made a precautionary landing. During landing roll, the right main landing gear collapsed. As a result of the right main landing gear collapse, the right wing sustained buckling damage. Examination of the right main landing gear by a FAA airworthiness inspector provided evidence of a failure of the torque tube assembly (part number 50-810240). No other deficiencies were noted during the examination. The part had a total of 5,616 cycles since factory overhaul and had been in service approximately 3.5 years. The part is required to be overhauled at 7,500 cycles or 5 years whichever occurs first. The affected part was removed and sent to the Board's Materials Laboratory. According to the laboratory analysis, the torque tube failed in fatigue. The origin of the fatigue could not be determined. The aircraft has since been repaired and returned to service with no further difficulties noted. ## Aircraft - Registration: N16NM (not matched to a registry record) - Reported make and model: Beech E90 - Category: Airplane - Serial number: LW62 - Airframe hours: 9965 - Engines: P&W PT6A-28 550 horsepower turbo prop - Damage: Substantial damage - Flight: Part 135 - Registered owner: Seven Bar Flying Service - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, August 5, 1997, 62 hours before - Departed: Q58, SANTA ROSA, NM - Destination: ABQ - Flight plan: IFR - Airport: ABQ, Albuquerque International, runway 21, 10,000 × 150 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 12,050 total, 200 in this make and model, 10,640 as pilot in command, 74 in the last 90 days, 24 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: 9,000 ft broken - Temperature: 84 °F, dew point 45 °F - Altimeter: 30.00 inHg - Observed at: ABQ, 1 nm away ## 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 19970831029039A](https://openairdocs.org/incident/19970831029039A), Aug 31, 1997: Beech E90, Albuquerque, NM, Substantial damage. Noise gear retract and unsafe light for landing. Right main folded landing torque tube had failed due fatigue. (.19) on August 31, 1997, at 1740 mountain… 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.