# NTSB WPR10LA221: Cessna 170A, N5765C, Minden, NV, April 30, 2010 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 30, 2010, 12:50 local (19:50 UTC) - Place: Minden, NV - Coordinates: 39.000556, -119.751113 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.0006&lon=-119.7511&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report March 16, 2011 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 75903 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR10LA221 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/75903/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=75903 - Page: https://openairdocs.org/ntsb/WPR10LA221 ## Probable cause A main landing gear collapse during the landing roll due to fatigue cracking and corrosion of the strut. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: main landing gear](https://openairdocs.org/ntsb-findings/01023210): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Cessna 170A, 4 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=2072304), [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not specified; cases with it: [Cessna 170A, 23 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=2072304), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Cessna 170A, 11 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2072304), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The certificated flight instructor (CFI) stated that, during the instructional flight, the pilot receiving instruction was practicing three-point landings in preparation for his tailwheel endorsement. The first landing was harder than normal due to a higher-than-normal sink rate. During the next landing attempt, the airplane yawed to the left. The CFI took over the airplane controls and corrected toward the runway centerline. While correcting, he heard a loud snapping noise followed by a loud scraping noise and felt the airplane make a sudden left turn. Postaccident examination revealed that the left landing gear strut fractured at the inboard end. Examination of the landing gear fracture surface by an NTSB materials laboratory metallurgist revealed evidence of fatigue cracking, an overstress fracture, and corrosion damage. ## Factual narrative On April 30, 2010, at 1250 Pacific daylight time, a Cessna 170A, N5765C sustained substantial damage following a left main landing gear collapse, during landing at the Minden-Tahoe Airport, Minden, Nevada. The airplane was registered to a private party and operated by the pilot under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The certificated flight instructor and pilot receiving instruction were not injured. The instructional flight departed Carson, Nevada at 1130 with a planned destination of Minden-Tahoe. Visual meteorological conditions prevailed, and no flight plan had been activated for the visual flight rules (VFR) flight. The certificated flight instructor (CFI) stated that the purpose of the flight was to practice for a tailwheel endorsement; the pilot receiving instruction was practicing three point landings. The first landing was “firm” due to a “higher than normal sink rate.” The next few attempts were low passes so the pilot receiving instruction could practice airspeed control. During the next landing attempt, the airplane “swerved” to the left. The CFI took control of the airplane and corrected toward the runway centerline. While correcting, he heard a loud snapping noise followed by a loud scraping noise and subsequent sudden left turn. The airplane slid, and came to a rest on the left edge of the runway. Post-accident examination of the airplane revealed the fuselage and left wing assembly sustained substantial damaged. Examination of the left main landing gear, by an airframe and powerplant mechanic, revealed that the left landing gear fractured at the inboard end. Photographs of the fracture surface were taken by the NTSB Investigator-in-charge and sent to the National Transportation Safety Board’s Materials laboratory in Washington, D.C. for further examination. An NTSB senior metallurgist reported that the main left landing gear fractured at the inboard end. The inboard fracture face contained a dark crescent-shaped fracture on the lower aft surface which is consistent with features of fatigue cracking. The remaining fracture surface contained a coarse grainy appearance, clear chevron markings, and a shear lip, which are consistent of an overstress fracture. Corrosion damage was also present on the worn surfaces of the left landing gear leg. ## Aircraft - Registration: [N5765C](https://openairdocs.org/aircraft/N5765C), registered now, S/N 19719, built 1950 (OpenAirDocs) - Reported make and model: CESSNA 170A - Registry model: [Cessna 170A](https://openairdocs.org/model/cessna-170a) (registry code 2072304) (OpenAirDocs) - Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 19719 - Airframe hours: 3730 - Engines: CONT MOTOR C145 SERIES 145 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, December 22, 2009, 10 hours before - Departed: KCXP, Carson City, NV - Destination: KMEV, Minden, NV - Flight plan: VFR - Airport: KMEV, Minden-Tahoe Airport, runway 34, 7,400 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 56; injuries: none; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review August 31, 2009; seat: right; flight hours: 2,924 total, 6 in this make and model, 2,924 as pilot in command, 57 in the last 90 days, 30 in the last 30 days, 1 in the last 24 hours - Pilot; age 48; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review April 4, 2009; seat: left; flight hours: 471 total, 8 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 46 °F, dew point 23 °F - Altimeter: 30.09 inHg - Observed at: KMEV ## 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 20100430032979A](https://openairdocs.org/incident/20100430032979A), Apr 30, 2010: Cessna 170A, Minden, NV, Substantial damage. On April 30, 2010 CFI 2112045, earl kessler, was conducting a flight check for a tail wheel endorsement in Minden, NV (mev). After touchdown on runway 34, the… ## Docket (6 files) The files NTSB released with the investigation on October 29, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=75903. 1.5 MB in all. - NTSB Lab Report (item 1, .PDF, 69 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40337477&FileExtension=.PDF&FileName=NTSB%20Lab%20Report-Redacted.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 - CFI (item 2, .PDF, 486 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40337434&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1%20-%20CFI-Redacted.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 - Student Pilot (item 3, .PDF, 795 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40337475&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1%20-%20Student%20Pilot-Redacted.PDF - Evidence Control Form (item 4, .PDF, 63 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40337479&FileExtension=.PDF&FileName=Evidence%20Control%20Form-Redacted.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 5, .PDF, 27 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40337480&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Redacted.PDF - Image 1. Landing Gear Fatigue (item 6, .PDF, 59 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40337481&FileExtension=.PDF&FileName=Image%201.%20Landing%20Gear%20Fatigue-Master.PDF 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.