# NTSB ERA13LA005: Cessna 310I, N8025M, Burlington, VT, October 2, 2012 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 2, 2012, 09:00 local (13:00 UTC) - Place: Burlington, VT - Coordinates: 44.471668, -73.153053 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.4717&lon=-73.1531&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Defining event: [Taxi-from runway: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report January 13, 2014 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: Cessna Aircraft Company, FAA\FSDO - NTSB case key (mKey): 85239 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA13LA005 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/85239/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=85239 - Page: https://openairdocs.org/ntsb/ERA13LA005 ## Probable cause The collapse of the left main landing gear due to a failure of the left main gear bellcrank pin for reasons that could not be determined because the pieces of the fractured bellcrank pin were not located. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: gear extension and retract sys](https://openairdocs.org/ntsb-findings/01023230): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Cessna 310I, 1 case](https://openairdocs.org/ntsb-findings/01023230/cases.md?model=2074224), [All aircraft, 416 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Cessna 310I, 4 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=2074224), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Taxi-from runway: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Cessna 310I, 3 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2074224), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The pilot reported that he landed the multiengine airplane without incident and while taxiing, the left main landing gear collapsed, which resulted in substantial damage to the left wing and left horizontal stabilizer. Subsequent examination of the airplane revealed that the left main gear bellcrank pin separated from its bushing. The pin was not located; however, metallurgical examination of the left main gear bellcrank and retraction link revealed significant deformation and fracturing of the bellcrank bushing consistent with a very large force applied along the axis of the link. The deformations on the link bore suggested the pin fractured inside the hole and exited the bore as two separated pieces. While overstress conditions seem probable, other failure modes, such as a significant fatigue crack cannot be ruled out since the pin fragments were not located. The airplane was manufactured about 38 years prior to the accident. It had been operated for about 3,675 total hours and 25 hours since its most recent annual inspection, which was performed about 2 months earlier. ## Factual narrative On October 2, 2012, about 0900 eastern daylight time, a Cessna 310I, N8025M, operated by a private individual, was substantially damaged while taxiing after landing at the Burlington International Airport (BTV), Burlington, Vermont. The private pilot and a passenger were not injured. Visual meteorological conditions prevailed and no flight plan had been filed for the local personal flight that was conducted under the provisions of 14 Code of Federal Regulations Part 91. According to the pilot, the airplane landed on runway 15, an 8,320-foot-long, asphalt and concrete runway without incident. He taxied toward the end of the runway and was making a right turn onto taxiway "C" when the left landing gear began to collapse. The left side of the airplane struck the ground, which resulted in substantial damage to the left wing and left horizontal stabilizer. Subsequent examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the left main gear bellcrank pin separated from its bushing. The pin was not located; however, the left main gear bellcrank and retraction link were removed and forwarded to the NTSB Materials Laboratory, Washington, D.C., for examination. The airplane was manufactured in 1964. According to an FAA inspector, at the time of the accident, the airplane had been operated for about 3,675 total hours and 25 hours since its most recent annual inspection, which was performed on August 8, 2012. Metallurgical examination revealed that the bellcrank and retraction link were connected by a pin inserted through a clevis on the long arm of the bellcrank and a pivot hole on the retraction link. One of the clevis tangs was bent outward and contained a small crack. Both flange bushings were fractured in similar manners on the inside of the clevis and the liberated halves of the bushings displayed features consistent with overstress, with no evidence of progressive cracking. The edges of the inner bore of the pivot hole in the retraction link were locally deformed radially outward in one direction on each side of the link, consistent with pin contact. [Additional information can be found in the Materials Laboratory Factual Report located in the public docket.] According to a representative from Cessna Aircraft Company, Cessna was not aware of any previous failures or separations involving only the main landing gear bellcrank pin on Cessna 310 series airplanes. ## Aircraft - Registration: [N8025M](https://openairdocs.org/deregistered/N8025M-2018-02-16), registration cancelled 2018-02-16, S/N 310I0025, built 1964 (OpenAirDocs) - Reported make and model: CESSNA 310I - Registry model: [Cessna 310I](https://openairdocs.org/model/cessna-310i) (registry code 2074224) (OpenAirDocs) - Registry engine: [Continental I0-470 series](https://openairdocs.org/engine/continental-i0-470-series) (registry code 17027, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 310I0025 - Year built: 1964 - Airframe hours: 3675 - Engines: Continental Motors Inc. IO-470U 265 horsepower reciprocating; Continental Motors Inc. IO-470U 265 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 8, 2012, 25 hours before - Departed: BTV, Burlington, VT - Destination: BTV, Burlington, VT - Airport: BTV, Burlington, runway 15, 8,320 × 150 ft, asphalt - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 32; injuries: none; private; airplane ratings: single-engine land, multi-engine sea; instrument ratings: airplane; medical: class 3, without waivers/limitations; last flight review September 14, 2012; seat: left; flight hours: 450 total, 160 in this make and model, 420 as pilot in command, 100 in the last 90 days, 25 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: 8,500 ft broken - Temperature: 57 °F, dew point 52 °F - Altimeter: 30.01 inHg - Observed at: BTV ## 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 20121002020999A](https://openairdocs.org/incident/20121002020999A), Oct 2, 2012: Cessna 310I, South Burlingto, VT, Substantial damage. On October 2, 2012, at approximately 0900 local time, a Cessna 310I, N8025M was substantially damaged at Burlington International Airport (btv), south… ## Docket (8 files) The files NTSB released with the investigation on November 19, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=85239. 16.1 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 955 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40402988&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Maintenace Records (excerpts) (item 2, .PDF, 342 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40403579&FileExtension=.PDF&FileName=Maintenace%20Records%20(excerpts)-Redacted.PDF - Materials Laboratory 15 - Factual Report of Group Chairman (item 3, .PDF, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40384003&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%20of%20Group%20Chairman-Master.PDF - Memorandum For Record (item 4, .PDF, 100 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40403578&FileExtension=.PDF&FileName=Memorandum%20For%20Record-Master.PDF - NTSB Party Form and Guidance (item 5, .PDF, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40403075&FileExtension=.PDF&FileName=NTSB%20Party%20Form%20and%20Guidance-Redacted.PDF - Photograph # 1 – View of damage to left horizontal stabilizer (Provided by FAA) (item 6, .PDF, 3.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40403068&FileExtension=.PDF&FileName=Photograph%20%23%201%20%E2%80%93%20View%20of%20damage%20to%20left%20horizontal%20stabilizer%20(Provided%20by%20FAA)-Master.PDF - Photograph # 2 – View of the left (separated) landing gear assembly (Provided by FAA) (item 7, .PDF, 4.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40403070&FileExtension=.PDF&FileName=Photograph%20%23%202%20%E2%80%93%20View%20of%20the%20left%20(separated)%20landing%20gear%20assembly%20(Provided%20by%20FAA)-Master.PDF - Photograph # 3 – View of the right (instact) landing gear assembly (Provided by FAA) (item 8, .PDF, 3.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40403072&FileExtension=.PDF&FileName=Photograph%20%23%203%20%E2%80%93%20View%20of%20the%20right%20(instact)%20landing%20gear%20assembly%20(Provided%20by%20FAA)-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.