# NTSB WPR15IA105: Evo13 Lancair Evolution, N3WB, San Carlos, CA, February 15, 2015 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: February 15, 2015, 11:45 local (19:45 UTC) - Place: San Carlos, CA - Coordinates: 37.509166, -122.246391 - Nearby events: https://openairdocs.org/map.md?lat=37.5092&lon=-122.2464&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: 3 uninjured - Status: Completed, report January 21, 2016 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Lancair International, Federal Aviation Administration - NTSB case key (mKey): 90741 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR15IA105 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/90741/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=90741 - Page: https://openairdocs.org/ntsb/WPR15IA105 ## Probable cause The collapse of the nose landing gear (NLG) due to the separation of the right trunnion pin from the NLG strut as a result of reverse-bending fatigue. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: nose/tail landing gear](https://openairdocs.org/ntsb-findings/01023220): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Evo13 LANCAIR EVOLUTION, 1 case](https://openairdocs.org/ntsb-findings/01023220/cases.md?model=05632N2), [All aircraft, 185 cases](https://openairdocs.org/ntsb-findings/01023220/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: [Evo13 LANCAIR EVOLUTION, 1 case](https://openairdocs.org/ntsb-events/094/sequence.md?model=05632N2), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Evo13 LANCAIR EVOLUTION, 1 case](https://openairdocs.org/ntsb-events/300/sequence.md?model=05632N2), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis The pilot reported that, during the landing roll, the nose landing gear (NLG) began to shimmy, which quickly became severe. The pilot applied back pressure on the control stick to reduce the weight on the NLG; however, the NLG collapsed about 2 to 3 seconds later. The airplane then skidded on the runway for about 1,000 ft before coming to a stop upright. A postincident examination of the NLG revealed that the right trunnion pin had separated at the base of the pin where it connected to the NLG strut arm. The fracture surface had unified crack fronts, consistent with fatigue crack progression. The fatigue cracks initiated from multiple origins on opposite sides of the trunnion pin, consistent with reverse-bending fatigue. Although the reverse bending could have resulted from the exceedance of the lateral limits of the tow bar parameters during ground towing operations, it could not be determined if such an exceedance occurred before the incident. The event that precipitated the reverse bending could not be determined. ## Factual narrative On February 15, 2015, about 1145 Pacific standard time, an EVO113 LLC Lancair Evolution, N3WB, sustained minor damage as a result of a nose landing gear collapse while on landing roll at the San Carlos Airport (SQL), San Carlos, California. The commercial pilot and two passengers were not injured. Visual meteorological conditions prevailed for the personal cross-country flight, which was being operated in accordance with 14 Code of Federal Regulations Part 91, and an instrument flight rules (IFR) flight plan was filed and active. The flight departed Gillespie Field (SEE), San Diego, California, at 1000, with SQL as the planned destinationAccording to a report submitted to the National Transportation Safety Board investigator-in-charge, the pilot reported that after touching down on both main landing gear, the nose wheel was lowered, followed by the power lever retarded aft into the BETA position to slow the airplane. The pilot stated that this was followed by an immediate shimmy, which quickly became severe. The control stick was then pulled back to alleviate pressure on the nose gear, but the nose gear collapsed about 2 to 3 seconds later. The airplane then skidded for about 1,000 feet on the runway surface before it veered to the right onto the grass adjacent to the runway. The aircraft then slid for about another 70 feet, after which it came to rest upright. An examination of the airplane failed to reveal any structural damage as a result of the gear collapse. At the request of the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on March 3, 2015, a Federal Aviation Administration aviation safety inspector supervised the removal of the right hand bearing block, serial number 111-0003, and the nose landing gear strut, serial number 432-0008. On March 17, 2015, both parts were shipped to the NTSB Materials Laboratory, Washington, D.C. for examination by a Materials Engineer. As a result of the examination, the engineer reported that the nose landing gear strut was submitted with a separated right trunnion pin, the separation having occurred at the base of the trunnion pin where it connected to the strut arm. The engineer further reported that the fracture surface of the portion of the trunnion pin that remained on the strut had extensive damage that obscured most of the fracture surface features. The engineer stated that there were 2 areas on the trunnion pin fracture surface that were generally flat, with a finely textured appearance and unified crack fronts consistent with fatigue crack progression. The fatigue cracking appeared to initiate from multiple origins on opposed sides of the trunnion pin, which is consistent with reversed bending fatigue. The fatigue cracking had propagated through approximately 35% of the cross-section from each side of the trunnion pin. Overstress separation covered the remaining 30% of the trunnion pin fracture surface between the two fatigue crack fronts. The size and shape of thefatigue crack areas were typical of reversed bending fatigue cracking in the presence of what is identified as a severe stress concentration. The engineer added that this was consistent with the fact that the separation of the trunnion pin occurred at the location where the trunnion pin attached to the strut arm. The mode operation which precipitated the reverse bending during towing, takeoff, or landing, was not determined during the investigation. (Refer to the NTSB Materials Laboratory Factual Report No. 15-079, which is appended to the docket for this report.) The airplane's Pilot's Operating Handbook states under Landing Gear, "Nose gear rotation is limited to 50 degrees either side of center." ## Aircraft - Registration: [N3WB](https://openairdocs.org/aircraft/N3WB), registered now, S/N EVO-013, built 2013 (OpenAirDocs) - Reported make and model: EVO13 LLC LANCAIR EVOLUTION - Registry model: [Evo13 LANCAIR EVOLUTION](https://openairdocs.org/model/evo13-lancair-evolution) (registry code 05632N2) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PT6A-135A](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-135a) (registry code 52260, turbo-prop) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: EVO-113 - Year built: 2013 - Airframe hours: 182.5 - Engines: Pratt & Whitney PT6A-135A 750 horsepower turbo prop - Damage: Minor damage - Flight: Personal, Part 91 - Operator: WR Brody, LLC - Registered owner: WR Brody, LLC - Airworthiness certificate: Special, Experimental (Special); Standard, Normal - Last inspection: Annual, August 21, 2014, 84 hours before - Departed: SEE, San Diego, CA - Destination: SQL, San Carlos, CA - Flight plan: IFR - Airport: SQL, San Carlos, runway 30, 2,600 × 75 ft, asphalt - Equipment: Auto-pilot, Electronic multifunction display, Electronic primary flight display, Onboard weather, Satellite tracking device, Stall warning system, ADS-B, Angle of attack indicator ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review June 14, 2014; seat: left; restraint: 3-point; flight hours: 1,532 total, 108 in this make and model, 1,532 as pilot in command, 39 in the last 90 days, 25 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: 66 °F, dew point 55 °F - Altimeter: 30.04 inHg - Observed at: SQL ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 20150215002909I](https://openairdocs.org/incident/20150215002909I), Feb 15, 2015: Evo13 LLC LANCAIR EVOLUTION, San Carlos, CA, Minor damage. Aircraft landed at sql runway 30, the nose gear collapsed. Aircraft slid 50 feet off the right side of runway striking a ground "parking" sign as the aircraft… ## Docket (6 files) The files NTSB released with the investigation on December 11, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=90741. 3.1 MB in all. - Materials Laboratory Factual Report (3 Embedded Images) (item 1, .PDF, 299 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40434929&FileExtension=.PDF&FileName=Materials%20Laboratory%20Factual%20Report%20(3%20Embedded%20Images)-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40434930&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Weather Data (item 3, .PDF, 51 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40434931&FileExtension=.PDF&FileName=Weather%20Data-Master.PDF - Excerpt from Pilot's Operating Handbook (item 4, .PDF, 392 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40434932&FileExtension=.PDF&FileName=Excerpt%20from%20Pilot%27s%20Operating%20Handbook-Master.PDF - Manufacturer's Authorization to Use Copyright Material (item 5, .PDF, 78 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40434933&FileExtension=.PDF&FileName=Manufacturer%27s%20Authorization%20to%20Use%20Copyright%20Material-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 6, .PDF, 425 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40434934&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-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.