# NTSB ANC20LA065: Cessna 180, N9185T, Anchorage, AK, July 5, 2020 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: July 5, 2020, 11:15 local (19:15 UTC) - Place: Anchorage, AK - Coordinates: 61.186668, -149.96527 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.1867&lon=-149.9653&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-flare/touchdown: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Alaska Regional Office - NTSB case key (mKey): 101546 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC20LA065 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/101546/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=101546 - Page: https://openairdocs.org/ntsb/ANC20LA065 ## Probable cause The failure of the left float bottom due to corrosion, which resulted in a loss of control during the water landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: wheel/ski/float](https://openairdocs.org/ntsb-findings/01023246): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Cessna 180C, 1 case](https://openairdocs.org/ntsb-findings/01023246/cases.md?model=2072608), [All aircraft, 48 cases](https://openairdocs.org/ntsb-findings/01023246/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-flare/touchdown: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Cessna 180C, 5 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=2072608), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) ## Analysis According to the pilot, and corroborated by video capturing the accident, during a normal touchdown in a float-equipped airplane, the left float dug into the water and the airplane veered abruptly and nosed over. A postaccident examination revealed a large hole in the bottom of the left float just forward of the step. Corrosion was present around the hole and no impact signatures were present on the bottom of the float. The circumstances of the accident are consistent with a loss of control during the water landing due to the failure of the left float due to corrosion. ## Factual narrative On July 5, 2020, about 1115 Alaska daylight time, a Cessna 180C airplane, N9185T, sustained substantial damage when it was involved in an accident near Anchorage, Alaska. The private pilot and one passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, they were returning from a remote lake to Lake Hood Airport (PALH) in the float-equipped airplane. The pilot stated that the departure was normal, with about 10 to 12 mph of wind on the lake, creating a light chop on the water's surface. Upon touchdown at PALH, the left float dug into the water and the airplane veered abruptly and nosed over. He stated that they quickly exited the sinking wreckage. A video captured the accident sequence and revealed that the airplane touched down on about the step of the floats before abruptly veering to the left. The right wing contacted the water and the airplane veered back to the right, and then to the left, before the airplane nosed over. A postaccident examination of the left float revealed a large hole in the bottom of the float just forward of the step. (See Figure 1.) Corrosion was present around the hole and no impact signatures were present on the bottom of the float. Figure 1 - Accident airplane at accident site, hole visible in left float. Photo courtesy of KTVA. ## Aircraft - Registration: [N9185T](https://openairdocs.org/aircraft/N9185T), registered now, S/N 50685, built 1960 (OpenAirDocs) - Reported make and model: Cessna 180 - Registry model: [Cessna 180C](https://openairdocs.org/model/cessna-180c) (registry code 2072608) (OpenAirDocs) - Registry engine: [Continental O-470 series](https://openairdocs.org/engine/continental-o-470-series) (registry code 17026, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 50685 - Year built: 1960 - Airframe hours: 5608 - Engines: Continental O-470R 230 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 30, 2019 - Departed: LHD, Anchorage, AK - Destination: LHD, Anchorage, AK - Airport: LHD, Lake Hood ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 81; injuries: none; private; airplane ratings: single-engine land, single-engine sea; medical: basicmed, unknown; seat: left; restraint: 3-point; flight hours: 1,500 total, 1,441 in this make and model, 1,500 as pilot in command, 7 in the last 90 days, 7 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 13 knots, gusting 21 - Visibility: 10 statute miles - Lowest ceiling: 10,000 ft broken - Temperature: 64 °F, dew point 52 °F - 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 20200705007549A](https://openairdocs.org/incident/20200705007549A), Jul 5, 2020: Cessna 180C, Anchorage, AK, Substantial damage. Pilot departed redshirt lake and stated conditions on takeoff were choppy but departure was uneventful. Upon landing at Lake Hood (palh) pilot states a normal… ## Docket (2 files) The files NTSB released with the investigation on January 19, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=101546. 1.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 544 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=10121482&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Photos (item 2, PDF, 3 pages, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=10121698&FileExtension=pdf&FileName=Photo%20array-Rel.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.