# NTSB WPR14LA134: Cessna 170B, N2252D, San Luis Obispo, CA, March 7, 2014 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: March 7, 2014, 13:40 local (21:40 UTC) - Place: San Luis Obispo, CA - Coordinates: 35.402221, -120.642776 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.4022&lon=-120.6428&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 January 5, 2016 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 88906 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR14LA134 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/88906/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=88906 - Page: https://openairdocs.org/ntsb/WPR14LA134 ## Probable cause Corrosion of the bulkhead assembly in the left main landing gearbox area, which resulted in the structural failure of the bulkhead and the subsequent landing gear collapse. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Fuselage: bulkheads (main fuselage)](https://openairdocs.org/ntsb-findings/01035312): Aircraft › Aircraft structures · Fatigue/wear/corrosion (probable cause); cases with it: [Cessna 170B, 1 case](https://openairdocs.org/ntsb-findings/01035312/cases.md?model=2072306), [All aircraft, 8 cases](https://openairdocs.org/ntsb-findings/01035312/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 170B, 9 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2072306), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The pilot reported that, shortly after a normal touchdown, the left main landing gear (MLG) collapsed, which resulted in substantial damage to the gearbox area. Review of videos from three surveillance cameras with different views of the landing corroborated the pilot's report that the landing was normal. Examination of the airplane revealed evidence of corrosion of the left MLG bulkhead assembly in the damaged gearbox area. The corrosion likely weakened the bulkhead's structure and resulted in the collapse of the left MLG. ## Factual narrative On March 7, 2014, about 1340 Pacific standard time, a Cessna 170B, N2252D, had the left main landing gear collapse during the landing roll at San Luis Obispo, California. The pilot was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The airline transport pilot and one passenger were not injured; the airplane sustained substantial damage. The local personal flight departed about 1300. Visual meteorological conditions prevailed, and no flight plan had been filed.The pilot reported that the touchdown was normal. Shortly thereafter, he heard and felt what he described as driving a car over the dummy dots on the road, and then the left main landing gear collapsed. The airframe sustained substantial damage in the area of the gearbox. A Federal Aviation Administration inspector retrieved and observed video from three surveillance cameras with different views of the landing. He felt that all three supported a normal landing. The inspector performed a postaccident examination of the airplane. Using an inspection mirror, he was able to see into the damaged belly of the fuselage, and observed corrosion of the structural bulkhead assembly in the damaged gearbox area. ## Aircraft - Registration: [N2252D](https://openairdocs.org/deregistered/N2252D-2018-03-13), registration cancelled 2018-03-13, S/N 20404, built 1952 (OpenAirDocs) - Reported make and model: CESSNA 170B - Registry model: [Cessna 170B](https://openairdocs.org/model/cessna-170b) (registry code 2072306) (OpenAirDocs) - Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 20404 - Year built: 1952 - Airframe hours: 2332 - Engines: Lycoming O-360-A1A 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Burch Loren W - Registered owner: Burch Loren W - Airworthiness certificate: Standard, Normal - Last inspection: Annual, November 11, 2013 - Departed: KSBP, San Luis Obispo, CA - Destination: KSBP, San Luis Obispo, CA - Airport: KSBP, San Luis Obispo, runway 29, 6,100 × 150 ft, asphalt - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 61; injuries: none; flight instructor, airline transport, commercial; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review June 28, 2012; seat: left; restraint: 3-point; flight hours: 3,535 total, 65 in this make and model, 3,291 as pilot in command, 14 in the last 90 days, 5 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 30° at 7 knots, gusting 18 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 41 °F - Altimeter: 30.04 inHg - Observed at: SBP ## 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 20140307003449A](https://openairdocs.org/incident/20140307003449A), Mar 7, 2014: Cessna 170B, San Luis Obispo, CA, Substantial damage. Aircraft was in left closed traffic for the option runway 29. After touchdown aircraft became uncontrolable and the left main gear collapsed causing the… ## Docket (3 files) The files NTSB released with the investigation on November 24, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=88906. 1.7 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 479 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40434295&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - FAA Inspector's Statement (item 2, .PDF, 56 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40434296&FileExtension=.PDF&FileName=FAA%20Inspector%27s%20Statement-Master.PDF - Cessna 170B Landing Gear Bulkhead Illustrated Parts Catalog (item 3, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40434297&FileExtension=.PDF&FileName=Cessna%20170B%20Landing%20Gear%20Bulkhead%20Illustrated%20Parts%20Catalog-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.