# NTSB ANC10LA026: Cessna 170B, N3492C, Anchorage, AK, March 17, 2010 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: March 17, 2010, 15:30 local (23:30 UTC) - Place: Anchorage, AK - Coordinates: 61.17472, -149.969726 - Nearby events: https://openairdocs.org/map.md?lat=61.1747&lon=-149.9697&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Defining event: [Taxi-to runway: Aircraft structural failure](https://openairdocs.org/ntsb-events/337) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report July 1, 2010 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA FSDO-03 - NTSB case key (mKey): 75531 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC10LA026 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/75531/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=75531 - Page: https://openairdocs.org/ntsb/ANC10LA026 ## Probable cause The structural failure of the right main landing gear leg, resulting in the collapse of the landing gear. ## 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: [Cessna 170B, 2 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=2072306), [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. - [Taxi-to runway: Aircraft structural failure](https://openairdocs.org/ntsb-events/337) (defining event); cases with it: [Cessna 170B, 1 case](https://openairdocs.org/ntsb-events/337/sequence.md?model=2072306), [All aircraft, 290 cases](https://openairdocs.org/ntsb-events/337/sequence.md) - [Taxi-to runway: Landing gear collapse](https://openairdocs.org/ntsb-events/094); 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 airline transport pilot was on a personal flight in a ski-equipped airplane. The pilot said that he was taxiing for takeoff when the right main landing gear leg broke near where the leg exits the fuselage. When the leg broke the right wing impacted the ground, bending the wing from the aileron outward toward the tip. An examination of the break showed a single linear break perpendicular to the leading edge of the gear leg. The break was about 6 inches from the gear leg mounting bolt hole, at the widest portion of the gear leg. The gear leg was retained for metallurgical examination by the Federal Aviation Administration. ## Factual narrative On March 17, 2010, about 1530 Alaska daylight time, a ski-equipped Cessna 170B airplane, N3492C, sustained substantial damage when the main landing gear collapsed during taxi for takeoff, at Lake Hood Seaplane Base, Anchorage, Alaska. The airplane was being operated by the pilot as a visual flight rules (VFR) personal local flight under Title 14, CFR Part 91, when the accident occurred. The airline transport pilot and sole passenger were not injured. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on March 18, the pilot said he was taxiing for takeoff on Lake Hood when the right main landing gear leg broke near where the leg exits the fuselage. He said when the leg broke the right wing impacted the ground, bending the wing from the aileron outward toward the tip. He said there were no mechanical problems with the airplane prior to the accident. During a meeting with the NTSB IIC on March 25, the pilot presented the broken gear leg to the IIC and an FAA air safety inspector. The break appeared to be a single linear break perpendicular to the leading edge of the gear leg. The break was about 6 inches from the gear leg mounting bolt hole, at the widest portion of the gear leg. No other damage was observed. The gear leg was retained by the FAA inspector for metallurgical examination. ## Aircraft - Registration: [N3492C](https://openairdocs.org/aircraft/N3492C), registered now, S/N 26535, built 1954 (OpenAirDocs) - Reported make and model: CESSNA 170B - Registry model: [Cessna 170B](https://openairdocs.org/model/cessna-170b) (registry code 2072306) (OpenAirDocs) - Registry engine: [Continental 0-300 series](https://openairdocs.org/engine/continental-0-300-series) (registry code 17022, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 26535 - Airframe hours: 4834 - Engines: CONT MOTOR O-300 SER 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Piscoya Thomas G - Registered owner: Piscoya Thomas G - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 11, 2009 - Departed: LHD, Anchorage, AK - Destination: LHD, Anchorage, AK - Airport: LHD, Lake Hood ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 50; injuries: none; flight engineer, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review January 8, 2009; seat: left; flight hours: 16,300 total, 1,600 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 50° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 37 °F, dew point 16 °F - Altimeter: 30.12 inHg - Observed at: LHD ## 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 20100317029799A](https://openairdocs.org/incident/20100317029799A), Mar 17, 2010: Cessna 170B, Anchorage, AK, Substantial damage. During taxi for the west water lane at lake Hood (lhd), right main landing gear leg broke completely through at the upper bend on leg near fuselage. When gear… ## Other investigations on N3492C (2) 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 ANC04LA112](https://openairdocs.org/ntsb/ANC04LA112), Sep 8, 2004: Cessna 170 (N3492C), Teller, AK, substantial damage. Probable cause: The pilot's selection of unsuitable terrain for takeoff, and his inadequate evaluation of the wind conditions, which resulted in a collision with an embankment during takeoff-initial climb. Factors… - [NTSB UNK64X0758](https://openairdocs.org/ntsb/UNK64X0758), Feb 29, 1964: Cessna 170 (N3492C), St Joseph, MO, substantial damage ## Docket (1 files) The files NTSB released with the investigation on April 2, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=75531. 847 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 847 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40327968&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.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.