# NTSB SEA96LA190: Aviat A-1, N56LG, Worland, WY, August 13, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 13, 1996, 11:50 local (17:50 UTC) - Place: Worland, WY - Coordinates: 44.000141, -107.949958 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.0001&lon=-107.9500&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report August 21, 1997 - Report: Approved by Office Director - NTSB case key (mKey): 42444 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA96LA190 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42444/pdf - Page: https://openairdocs.org/ntsb/SEA96LA190 ## Probable cause overload failure of the landing gear axle, after its design stress limits had been exceeded at some undetermined time. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, landing - landing gear,axle - overload (cause) - Nose over, landing ## Analysis The pilot reported that as the airplane touched down on the turf runway, the right main landing gear collapsed. The airplane then veered to the right and nosed over. A postaccident examination revealed that the right main landing gear had separated at the axle. A metallurgical examination of the break revealed that the fracture was due to overload that started on the bottom of the tube and progressed upwards. The specialist conducting the test stated that the fracture progression was consistent with a large upward load on the end of the axle such as would be experienced with a hard landing. However, the time of the overload was not determined. ## Factual narrative On August 13, 1996, at 1150 mountain daylight time, an Aviat Inc. A-1, N56LG, registered to Scott Erickson Aviation and operated by the pilot as a 14 CFR Part 91 personal flight, nosed over during the landing roll on a dirt airstrip near Worland, Wyoming. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane was substantially damaged and the commercial pilot and his passenger were not injured. The flight had departed from Fairburn, South Dakota, approximately two hours prior to the accident. The pilot reported in a written statement, that he landed the airplane into the wind. As the airplane touched down, the right main landing gear collapsed. The airplane veered to the right and nosed over. After the accident, the right main landing gear tire was found approximately 100 feet from the airplane, to the left of the runway. A metallurgical inspection of the right side wheel axle was performed by AADFW, Inc. Euless, Texas. The results of the tests revealed that the chemical and physical properties of the tube were acceptable and no defects in the material quality were noted. The specialist performing the test reported that "the fracture was an overload fracture that started on the bottom of the tube and progressed upwards. This fracture progression is consistent with a large upward load on the end of the axle such as would be experienced in a hard landing." The fracture passed through a toe weld, however, the specialist determined that the weld had nothing to do with the initiation of the fracture. The timing of the overload failure was not determined. ## Aircraft - Registration: [N56LG](https://openairdocs.org/deregistered/N56LG-2000-07-13), registration cancelled 2000-07-13, S/N 1313 (OpenAirDocs) - Reported make and model: AVIAT A-1 - Registry model: [Aviat A-1](https://openairdocs.org/model/aviat-a-1) (registry code 2210302) (OpenAirDocs) - Category: Airplane - Serial number: 1313 - Airframe hours: 63 - Engines: Lycoming O-360-A1P 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Scott Erickson Aviation - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 10, 1996, 63 hours before - Departed: 3VO, FAIRBURN, SD - Airport: WRL, Worland Muni, runway 10, 2,500 × 50 ft, grass/turf ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; flight instructor, commercial; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: front; flight hours: 524 total, 61 in this make and model, 406 as pilot in command, 63 in the last 90 days, 26 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 90° at 5 knots - Visibility: 15 statute miles - Lowest ceiling: none - Temperature: 90 °F, dew point 39 °F - Altimeter: 30.00 inHg ## 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 19960813022549A](https://openairdocs.org/incident/19960813022549A), Aug 13, 1996: Chris A1, Worland, WY, Substantial damage. Right main collapsed on landing. Axle had failed due to some prior hard landings. 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.