# NTSB WPR11LA063: Champion 7KCAB, N5101X, Rialto, CA, November 27, 2010 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: November 27, 2010, 10:30 local (18:30 UTC) - Place: Rialto, CA - Coordinates: 34.129165, -117.40139 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.1292&lon=-117.4014&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report March 8, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 77883 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11LA063 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/77883/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=77883 - Page: https://openairdocs.org/ntsb/WPR11LA063 ## Probable cause Fatigue cracking of the left main landing gear leg, which resulted in a gear collapse during landing. ## 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 · Failure (probable cause); cases with it: [Champion 7KCAB, 1 case](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=21101P3), [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md) - [Landing gear system: main landing gear](https://openairdocs.org/ntsb-findings/01023210): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Champion 7KCAB, 1 case](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=21101P3), [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/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: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330); cases with it: [Champion 7KCAB, 3 cases](https://openairdocs.org/ntsb-events/330/sequence.md?model=21101P3), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Champion 7KCAB, 2 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=21101P3), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The certified flight instructor stated that he and the pilot receiving instruction were practicing landings in the tailwheel-equipped airplane. He said that during a wheel landing, with the pilot receiving instruction manipulating the flight controls, the airplane's left main landing gear collapsed, and the airplane skidded to the left and contacted a taxiway sign. The instructor reported that the wind was calm at the time of the accident. Postaccident metallurgical examination revealed that the left landing gear fractured at its inboard end due to fatigue cracking and corrosion damage. ## Factual narrative On November 27, 2010, at 1030 Pacific standard time, an American Champion 7KCAB tailwheel equipped airplane, N5101X, sustained substantial damage to the fuselage and left wing assembly following a main gear collapse during landing at the Rialto Municipal Airport, Rialto, California. The certified flight instructor (CFI) and private pilot receiving tail wheel instruction were not injured. The airplane was operated by Foothill Flying Club as a visual flight rules (VFR) instructional flight under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. Visual meteorological conditions prevailed at the time of the accident. No flight plan was filed for the instructional flight that originated from Upland, California, at 0930. In a written report to the National Transportation Safety Board (NTSB) investigator-in-charge, the CFI stated that during the wheel landing, with the private pilot manipulating the flight controls, the airplane's left main landing gear collapsed. He stated that the airplane skidded to the left, and contacted a taxiway sign before it came to rest. The instructor reported that the wind was calm during the timeframe of the accident. The fractured landing gear leg was shipped to the NTSB Materials Laboratory in Washington, D.C. for further examination. An NTSB senior metallurgist reported that examination of the left landing gear leg revealed that it fractured at the inboard end, approximately where the spring passes through the fillet plate and seal. The inboard fracture face had a dark crescent-shaped fracture on the aft edge. The smooth dark appearance, the presence of a crack arrest mark, and the presence of ratchet marks of this crescent-shaped region is consistent with the features of fatigue cracking from multiple origins. The remainder of the fracture face exhibited a coarse, grainy appearance, clear chevron markings originating adjacent to the fatigue crack, and a shear lip. All features were found consistent with overstress fracture. The paint on the underside of the spring had been worn away in the same region as the fracture, where the support wedges contact the surface of the spring. Corrosion damage is also present on the worn surfaces. ## Aircraft - Registration: [N5101X](https://openairdocs.org/aircraft/N5101X), registered now, S/N 164, built 1969 (OpenAirDocs) - Reported make and model: CHAMPION 7KCAB - Registry model: [Champion 7KCAB](https://openairdocs.org/model/champion-7kcab) (registry code 21101P3) (OpenAirDocs) - Registry engine: [Lycoming IO-320 series](https://openairdocs.org/engine/lycoming-io-320-series) (registry code 41509, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 164 - Airframe hours: 1722 - Engines: LYCOMING IO-320 SERIES 150 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Foothill Flying Club - Registered owner: Findley, John - Airworthiness certificate: Standard, Aerobatic; Standard, Normal - Last inspection: Annual, April 23, 2010 - Departed: KCCB, Cable Airport, CA - Destination: L67, Rialto, CA - Airport: L67, Rialto Municipal, runway 24, 4,500 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 69; 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 9, 2010; seat: rear; flight hours: 3,516 total, 30 in this make and model, 3,049 as pilot in command, 83 in the last 90 days, 25 in the last 30 days, 3 in the last 24 hours - Pilot; age 27; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review August 16, 2010; seat: front; flight hours: 94 total, 3 in this make and model, 32 as pilot in command, 22 in the last 90 days, 7 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 57 °F, dew point 14 °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 20101127053409A](https://openairdocs.org/incident/20101127053409A), Nov 27, 2010: Champion 7KCAB, Rialto, CA, Substantial damage. The aircraft departed cable airport and flew to Rialto airport to practice touch-and-go's on runway 24. On the 5th landing a loud snap was heard. The left gear… ## Other investigations on N5101X (1) 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. - [NTSB DEN72DTM03](https://openairdocs.org/ntsb/DEN72DTM03), Jul 30, 1971: Champion 7KCAB (N5101X), Lehi, UT, destroyed ## Docket (5 files) The files NTSB released with the investigation on January 20, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=77883. 3.8 MB in all. - Materials Laboratory 15 - Factual Report of Group Chairman (10 Embedded Photos) (item 1, .PDF, 10 photos, 793 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360875&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%20of%20Group%20Chairman%20(10%20Embedded%20Photos)-Master.PDF - Materials Laboratory Correspondence (item 2, .PDF, 412 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360401&FileExtension=.PDF&FileName=Materials%20Laboratory%20Correspondence-Redacted.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 3, .PDF, 699 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40361724&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 4, .PDF, 239 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360403&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Redacted.PDF - Image 1. View of aircraft at final resting place. (item 5, .PDF, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360404&FileExtension=.PDF&FileName=Image%201.%20View%20of%20aircraft%20at%20final%20resting%20place.-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.