# NTSB WPR11LA273: Schweizer G-164B, N3627G, Marysville, CA, June 21, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 21, 2011, 10:35 local (17:35 UTC) - Place: Marysville, CA - Coordinates: 39.097778, -121.569725 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.0978&lon=-121.5697&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report November 22, 2011 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration FSDO - NTSB case key (mKey): 80840 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11LA273 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/80840/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=80840 - Page: https://openairdocs.org/ntsb/WPR11LA273 ## Probable cause The separation of the right main landing gear during takeoff, due to fatigue. ## 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: [Schweizer G-164B, 2 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=8059055), [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. - [Takeoff: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) (defining event); cases with it: [Schweizer G-164B, 1 case](https://openairdocs.org/ntsb-events/338/sequence.md?model=8059055), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) - [Landing-landing roll: Abnormal runway contact](https://openairdocs.org/ntsb-events/090); cases with it: [Schweizer G-164B, 2 cases](https://openairdocs.org/ntsb-events/090/sequence.md?model=8059055), [All aircraft, 1,506 cases](https://openairdocs.org/ntsb-events/090/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Schweizer G-164B, 7 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=8059055), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis During the takeoff roll of the aerial application flight, the right main landing gear separated from the airplane's fuselage. The pilot continued the takeoff from the dirt airstrip, and elected to land at a local airport. During the landing roll, the airplane departed the runway sustaining substantial damage to the lower left wing. Examination of the right main landing gear spring leg revealed that the outboard segment had separated from the airplane at its root, adjacent to the airframe support structure. The fracture surfaces indicated a fatigue failure emanating from an area of corrosion on the lower surface of the spring. ## Factual narrative On June 21, 2011, about 1035 Pacific daylight time, a Schweizer Airplane Corp. G-164B, N3627G, departed the runway during landing at Yuba County Airport, Marysville, California. Sutter Butte Dusters, Inc., was operating the airplane under the provisions of Title 14 Code of Federal Regulations (CFR) Part 137. The commercial pilot was not injured, and the airplane sustained substantial damage. The aerial application flight departed from a dirt strip near Gridley, California, about 0930. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot reported that during the takeoff roll, just prior to rotation, the right main landing gear separated from the fuselage. He continued the takeoff and elected to land at Yuba County Airport. During the landing roll, the airplane departed the runway sustaining substantial damage to the lower left wing. Examination of the right main landing gear leg revealed that the outboard segment had separated from the airplane at its root, with the fracture surface in line with the outboard edge of the airframe support structure. The outboard section of the spring leg was sent to the NTSB Office of Research and Engineering, Materials Laboratory Division for examination. Visual examinations of the fracture surface and surrounding material revealed shear lips and granular surface traces initiating from a discolored thumbnail region located slightly forward of the middle point of the lower spring surface. Inspection of the thumbnail region revealed two bands of oxidation containing microscopic fracture features. The inner band was more heavily oxidized, and contained features indicative of fatigue progression. The fatigue initiated on the lower surface and propagated upward into the spring material. The fatigue region measured approximately 0.163 inch wide and had penetrated about 0.072 inch into the gear material. The second outer band displayed lighter colored oxidization features. The overall thumbnail region measured about 0.317 inch wide and had penetrated 0.137 inch into the gear. Outside of the oxidized area the fracture displayed ridges and granular features was consistent with rapid overstress emanating from the thumbnail. Examination of the lower surface of the spring revealed corrosion pitting at the thumbnail origin, and along the line of the fracture. The paint in the area appeared partially intact. Corrosion products were visible on the surface, and pitting was visible under the paint. The paint was also blistered in many areas. The fixed-gear, tailwheel equipped biplane, serial number 729B, was manufactured in 1983. The airplane’s classification was restricted, with a category of agriculture and pest control. A review of the maintenance logbooks revealed a total airframe time of 13,509 hours at the last 100-hour annual inspection, which occurred on June 16, 2011, 10 flight hours prior to the accident. ## Aircraft - Registration: [N3627G](https://openairdocs.org/aircraft/N3627G), registered now, S/N 729 B, built 1983 (OpenAirDocs) - Reported make and model: SCHWEIZER AIRCRAFT CORP G-164B - Registry model: [Schweizer G-164B](https://openairdocs.org/model/schweizer-g-164b) (registry code 8059055) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 729 B - Airframe hours: 13509 - Engines: Pratt and Whitney PT6A 600 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Sutter Butte Dusters Inc - Registered owner: Sutter Butte Dusters Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, June 16, 2011, 10 hours before - Departed: PVT, Gridley, CA - Destination: MYV, Marysville, CA - Flight plan: Unknown - Airport: MYV, Yuba County, runway 32, 6,006 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 60; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review January 6, 2011; seat: single; flight hours: 14,000 total, 10,000 in this make and model, 13,975 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 91 °F, dew point 57 °F - Altimeter: 29.77 inHg - Observed at: MYV ## 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 20110621012939A](https://openairdocs.org/incident/20110621012939A), Jun 21, 2011: Schweizer Aircraft Corp G-164B, Marysville, CA, Destroyed. During takeoff just prior to liftoff from an ag dirt-strip the right main tire wheel and gear assembly broke off and bounced up and struck right aileron. The… ## Other investigations on N3627G (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 LAX89DVG07](https://openairdocs.org/ntsb/LAX89DVG07), Jul 4, 1989: Schweizer G-164B (N3627G), Willows, CA, substantial damage. Probable cause: FAILURE OF THE CONNECTING ROD ON #1 CYLINDER OF THE AIRCRAFT POWERPLANT. ## Docket (4 files) The files NTSB released with the investigation on October 4, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=80840. 1.7 MB in all. - Materials Laboratory 15 - Factual Report 11-086 (3 images) (item 1, .PDF, 889 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40352679&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%2011-086%20(3%20images)-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 574 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353775&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Evidence Control Form (item 3, .PDF, 84 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353778&FileExtension=.PDF&FileName=Evidence%20Control%20Form-Redacted.PDF - Photo 1: Forward View of Airplane (item 4, .PDF, 111 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353776&FileExtension=.PDF&FileName=Photo%201%3A%20Forward%20View%20of%20Airplane-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.