# NTSB ANC18LA067: Cessna U206, N441GR, Pedro Bay, AK, August 18, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 18, 2018, 10:00 local (18:00 UTC) - Place: Pedro Bay, AK - Coordinates: 59.796943, -154.129714 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=59.7969&lon=-154.1297&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) - Highest injury: No injuries - Injuries: 6 uninjured - Status: Completed, report June 8, 2020 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Federal Aviation Administration - NTSB case key (mKey): 98182 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC18LA067 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/98182/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=98182 - Page: https://openairdocs.org/ntsb/ANC18LA067 ## Probable cause The fatigue fracture of both main landing gear legs during the landing roll, which resulted in the collapse and separation of both main landing gear legs. ## 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 U206F, 2 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=2073333), [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md) - [Landing gear system: main landing gear](https://openairdocs.org/ntsb-findings/01023210): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Cessna U206F, 2 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=2073333), [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. - [Landing-landing roll: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) (defining event); cases with it: [Cessna U206F, 2 cases](https://openairdocs.org/ntsb-events/338/sequence.md?model=2073333), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) ## Analysis According to the pilot, before landing on the tidal beach, he conducted two passes over the landing area to check for debris and determine wind direction. He stated that, after touchdown on the beach, the airplane felt like it had a flat tire and subsequently veered to the right. The airplane came to rest in a left-wing-low attitude on a tidal mudflat and sustained substantial damage to the left wing, left horizontal stabilizer, and left elevator. The pilot examined the airplane and noted that both main landing gear legs had separated just above the main axle attach point. A laboratory examination revealed that both main landing gear legs failed due to fatigue cracking. ## Factual narrative On August 18, 2018, about 1000 Alaska daylight time, a Cessna U206F airplane, N441GR, sustained substantial damage while landing at a remote unimproved tidal beach about 36 miles east of Pedro Bay, Alaska. The airplane was registered to AK Air Leasing, LLC and operated by K Bay Air, LLC as a visual flight rules (VFR) on-demand commercial flight under the provisions of 14 Code of Federal Regulations Part 135 when the accident occurred. The commercial pilot and five passengers were not injured. Visual meteorological conditions prevailed, and company flight following procedures were in effect. The flight departed Homer, Alaska, about 0900. According to the pilot, before landing on the tidal beach, he conducted two passes over the landing area to check for debris and determine wind direction. After a stable approach, the left main and uphill tire touched down first followed by the right main tire. The pilot stated that after touchdown, it "felt like" the airplane had a flat tire and it subsequently veered to the right and came to rest in a left wing low attitude on a tidal mudflat. The airplane sustained substantial damage to the left wing, left horizontal stabilizer and left elevator. An initial examination of the airplane, by the pilot, revealed that both main landing gear legs separated just above the main axle attach point. An examination by the National Transportation Safety Board (NTSB) Materials Laboratory revealed that both main landing gear legs exhibited chevron marks leading to a thumbnail region consistent with fatigue cracking. The NTSB Materials Laboratory examination report is in the public docket for this accident. ## Aircraft - Registration: [N441GR](https://openairdocs.org/deregistered/N441GR-2019-04-17), registration cancelled 2019-04-17, S/N U20601801, built 1972 (OpenAirDocs) - Reported make and model: Cessna U206 (F) - Registry model: [Cessna U206F](https://openairdocs.org/model/cessna-u206f) (registry code 2073333) (OpenAirDocs) - Registry engine: [Continental IO-520-F](https://openairdocs.org/engine/continental-io-520-f) (registry code 17237, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: U20601801 - Year built: 1972 - Airframe hours: 4480 - Engines: Continental IO-520-F 300 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Operator: K Bay Air LLC - Registered owner: AK Air Leasing LLC - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, August 10, 2018 - Departed: PAHO, Homer, AK - Destination: Pedro Bay, AK - Flight plan: Company VFR - Equipment: Handheld GPS, Auto-pilot ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review July 29, 2018; seat: left; restraint: 3-point; flight hours: 4,400 total, 1,660 in this make and model, 4,300 as pilot in command, 204 in the last 90 days, 60 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: 6,500 ft overcast - Temperature: 54 °F, dew point 48 °F - Altimeter: 30.29 inHg - Observed at: PAHO ## 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 20180818018509A](https://openairdocs.org/incident/20180818018509A), Aug 18, 2018: Cessna U206F, Chinitna Bay, AK, Substantial damage. On August 18, 2018 airman was flying N441GR, a CE-U206F to Chinitna Bay for the purpose of bear viewing. Pilot plus 5 passengers. Airman performed a preflight… ## Docket (3 files) The files NTSB released with the investigation on April 24, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=98182. 3.9 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40483118&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Materials Laboratory Factual Report (item 2, .PDF, 265 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40483119&FileExtension=.PDF&FileName=Materials%20Laboratory%20Factual%20Report-Master.PDF - Photos (item 3, .PDF, 69 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40483120&FileExtension=.PDF&FileName=Photos-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.