# NTSB LAX01TA284: Aero Commander 500S, N975AA, Elko, NV, August 21, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Final report - Date: August 21, 2001, 15:03 local (22:03 UTC) - Place: Elko, NV - Coordinates: 40.949783, -115.78997 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.9498&lon=-115.7900&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report November 25, 2003 - Report: Approved by Office Director - Parties: FAA FSDO, US Department of the Interior - NTSB case key (mKey): 53356 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX01TA284 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/53356/pdf - Page: https://openairdocs.org/ntsb/LAX01TA284 ## Probable cause The main landing gear collapsed for undetemined reasons. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Gear collapsed, landing - roll - reason for occurrence undetermined (cause) ## Analysis Both main landing gear collapsed about 100 feet down the runway on the landing roll. The skid ground off the belly skin and damaged several structural airframe components. One of the observers in the airplane was also a pilot. He observed three green landing gear lights, and he and the pilot both visually checked that the landing gear was down. He observed the pilot maintain one hand on the control yoke and the other on the throttle throughout the landing and landing roll. A physical check of the gear revealed no anomalies and the gear functioned normally when placed on jacks. The actuators functioned properly when checked on a test bench. The Aero Commander uses hydraulic pressure to keep the gear locked, and the landing gear handle has two positions, gear up and gear down. ## Factual narrative On August 21, 2001, at 1503 Pacific daylight time, an Aero Commander 500S, N975AA, had both main landing gear collapse on landing at Elko, Nevada. Avcenter, Inc., was operating the airplane as a public-use fire command and control flight under the provisions of 14 CFR Part 91. The commercial pilot and two passengers were not injured; the airplane sustained substantial damage. The local flight departed Elko about 1330. Visual meteorological conditions prevailed, and a company VFR flight plan had been filed. The operator reported that the airplane touched down and began its landing roll. About 100 feet down the runway, both main landing gear collapsed. The resulting skid ground off the belly skin and damaged several structural airframe components. One of the observers in the airplane was also a pilot. He observed three green landing gear lights, and told the operator that he and the pilot both visually checked that the landing gear was down. He observed the pilot maintain one hand on the control yoke and the other on the throttle throughout the landing and landing roll. A Safety Board investigator interviewed a maintenance supervisor at Aero Air, Hillsboro, Oregon, who performed the tests on the landing gear after the accident. The supervisor stated that the plane was ferried to Aero Air with its landing gear in the locked position. Aero Air personnel physically checked the landing gear by putting the airplane on jacks and swinging the gear. The physical check was satisfactory, and everything worked normally. As a precaution, the operator asked them to check the actuators. The actuators were bench tested, and they functioned normally. Aero Air also resealed them, and tested them once more, and everything functioned normally. They did not perform any checks on the hydraulic system. In the same conversation the supervisor stated that the landing gear is held in place by hydraulic pressure, and when it passes center it uses elastic bungee cords. He also noted that the landing gear handle is a two-position handle, gear up, and gear down. ## Aircraft - Registration: [N975AA](https://openairdocs.org/aircraft/N975AA), registered now, S/N 3175, built 1974 (OpenAirDocs) - Reported make and model: Aero Commander 500S - Registry model: [Aero Commander 500 S](https://openairdocs.org/model/aero-commander-500-s) (registry code 0141107) (OpenAirDocs) - Registry engine: [Lycoming IO-540 series](https://openairdocs.org/engine/lycoming-io-540-series) (registry code 41530, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 3175 - Airframe hours: 3990 - Engines: Lycoming IO-540-E1B5 290 horsepower reciprocating; Lycoming IO-540-E1B5 290 horsepower reciprocating - Damage: Substantial damage - Flight: Part 91 - Registered owner: Avcenter, Inc. - Airworthiness certificate: Standard, Utility - Last inspection: 100 hour, August 21, 2001, 2 hours before - Departed: EKO, ELKO, NV - Flight plan: Company VFR - Airport: EKO, Elko Regional, runway 23, 7,214 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 28; injuries: none; commercial; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; last flight review June 12, 2001; seat: left; flight hours: 2,810 total, 200 in this make and model, 3,700 as pilot in command, 200 in the last 90 days, 80 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 32 °F - Altimeter: 29.95 inHg - Observed at: EKO ## 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 20010821022829A](https://openairdocs.org/incident/20010821022829A), Aug 21, 2001: Gulstm 500S, Elko, NV, No damage. (-23) During roll-out after landing, the left main gear, followed by right main gear, collapsed causing damage to the lower fuselage skins. 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.