# NTSB LAX98TA251: Aero Commander 690, N349AC, Ely, NV, July 28, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Final report - Date: July 28, 1998, 15:00 local (22:00 UTC) - Place: Ely, NV - Coordinates: 39.420112, -115.000267 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.4201&lon=-115.0003&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report February 16, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 43562 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX98TA251 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43562/pdf - Page: https://openairdocs.org/ntsb/LAX98TA251 ## Probable cause The failure and separation of the left main gear wheel halves due to overload as a result of excessive air pressure. A contributing factor was the inadequate maintenance/service of the main gear tires. ## 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,tire - pressure excessive (cause) - maintenance,service of aircraft/equipment - inadequate (contributing factor) - landing gear,wheel - miscellaneous,bolt/nut/fastener/clamp/spring - stripped thread - miscellaneous,bolt/nut/fastener/clamp/spring - overload (cause) ## Analysis According to the pilot and observer's statements, they were taxing out for departure when the left main wheel came off its axle. As the strut grounded on the taxiway, the left rear wing spar was fractured and fuselage crown skin wrinkled. Examination of the aircraft revealed that the left wheel was separated into its two halves and the tire had come off the wheel. All ten nuts were stripped off the bolts that hold the wheel halves together. The air pressure in the right tire was measured with a gage that only goes to 125 psi; the pressure in the tire pegged the gage at that value. According to the aircraft's flight manual, the maximum main landing gear tire pressure should be 60 psi. ## Factual narrative On July 28, 1998, at 1500 hours Pacific daylight time, an Aero Commander 690, N349AC, sustained left wing spar damage following left wheel separation from its strut while taxing for takeoff at the Ely, Nevada, airport. The aircraft was operated as public-use by the Bureau of Land Management, U.S. Department of the Interior, for fire reconnaissance missions. Visual meteorological conditions prevailed and a company VFR flight plan was filed. The aircraft sustained substantial damage and the airline transport pilot and his observer were not injured. The flight was originating at the time for a local area fire-spotting mission. According to the pilot and observer's statements, they were taxing out for departure when the left main wheel came off its axle. As the strut grounded on the taxiway, rear wing spar and fuselage crown skin damage occurred. The aircraft was examined by investigators from the Office of Aircraft Services (OAS), U.S. Department of the Interior. They reported that the rear spar was fractured in the area of the wheel well. Left wing and fuselage crown skin was wrinkled and several wing ribs were damaged. The left wheel was found separated into its two halves and the tire had come off the wheel. All ten nuts were stripped off the bolts that hold the wheel halves together. The air pressure in the right tire was measured with a gage that only goes to 125 psi; the pressure in the tire pegged the gage at that value. According to the aircraft's flight manual, the maximum main landing gear tire pressure should be 60 psi. According to the OAS investigators, 1 week prior to the accident when the airplane was still in Fairbanks, Alaska, the pilot asked a mechanic to add air to the main tires because they looked low. The mechanic measured the pressure in the tires at 80 psi and informed the pilot that the tires were inflated correctly. ## Aircraft - Registration: [N349AC](https://openairdocs.org/deregistered/N349AC-1999-11-24), registration cancelled 1999-11-24, S/N 11032 (OpenAirDocs) - Reported make and model: Aero Commander 690 - Registry model: [Aero Commander 690](https://openairdocs.org/model/aero-commander-690) (registry code 0141720) (OpenAirDocs) - Category: Airplane - Serial number: 11032 - Airframe hours: 4775 - Engines: Airesearch TPE-331-5 717 horsepower turbo prop - Damage: Substantial damage - Flight: Public aircraft, Part 91 - Operator: Blm, U.S. Dept Of Interior, doing business as Alaska Fire Section - Registered owner: Horizons Unlimited - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, June 14, 1998, 57 hours before - Departed: ELY - Flight plan: Company VFR - Airport: ELY, Yelland Field ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 61; airline transport, flight instructor; airplane ratings: multi-engine land, single-engine sea, single-engine land, multi-engine sea; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 20,000 total, 2,200 in this make and model, 18,300 as pilot in command, 145 in the last 90 days, 70 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 360° at 5 knots - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 81 °F ## 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 19980728029949A](https://openairdocs.org/incident/19980728029949A), Jul 28, 1998: Gulstm 690, Ely, NV, Substantial damage. According to pilot and observer's statements, they were taxiing out for departure when the left main wheel came off its axle. As the strut grounded on the… 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.