# NTSB WPR22LA016: Cessna 180H, N926LL, Kalispell, MT, October 12, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: October 12, 2021, 13:00 local (19:00 UTC) - Place: Kalispell, MT - Coordinates: 48.177404, -114.30419 - Nearby events: https://openairdocs.org/map.md?lat=48.1774&lon=-114.3042&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 104134 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR22LA016 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/104134/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=104134 - Page: https://openairdocs.org/ntsb/WPR22LA016 ## Probable cause The pilot’s failure to maintain directional control during landing, which resulted in a ground loop and a runway excursion. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Cessna 180H, 29 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=2072618), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Cessna 180H, 32 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2072618), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/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: Runway excursion](https://openairdocs.org/ntsb-events/300) (defining event); cases with it: [Cessna 180H, 15 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=2072618), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis The pilot of the tailwheel-equipped airplane reported that, during the landing roll, the airplane veered to the right, exited the runway, and contacted terrain. The left wing, left aileron, left horizontal stabilizer, and elevator sustained substantial damage. Examination of the wreckage revealed no mechanical malfunctions or failures that would have precluded normal operation; however, the alignment of the main landing gear could not be determined due to the separation of the left main landing gear. Several days before the accident, the airplane had undergone maintenance during which the tires, wheels and brakes were replaced. According to the supplemental type certificate (STC) for the new tires, the tundra tires reduce the directional stability and controllability, and increase the tendency to ground loop during takeoff and landing ground rolls. Based on the available information, the circumstances of the accident are consistent with the pilot’s failure to maintain directional control during the landing roll. ## Factual narrative On October 12, 2021, about 1300 mountain daylight time, a Cessna 180 airplane, N926LL, was substantially damaged when it was involved in an accident near Kalispell, Montana. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot of the tailwheel-equipped airplane, she received a clearance to land on runway 20 but, because of a tailwind, performed a go-around. She then requested and was cleared to land on runway 02. Upon touchdown, the airplane veered abruptly to the right, skipped several times, and departed the runway to the right, where the left wing contacted terrain. The pilot reported that she did not know if a mechanical malfunction or failure had occurred. A tower controller reported that the pilot was cleared to land on runway 20 and went around after bouncing the airplane a few times. The pilot then requested to land on runway 02. The controller cleared the pilot to land on runway 02, where the airplane then “skidded off east of runway mid-field.” The airplane came to rest upright in open terrain adjacent to the runway. The left wing and aileron exhibited a sharp bend upwards from the tip to about 30 inches inboard. The right wing was bent downward, and the right strut buckled. The left horizontal stabilizer and elevator were bent upwards about mid-span. Examination of the landing gear revealed that the left landing gear assembly separated from the fuselage. The landing gear exhibited a wheel alignment shim on the left side-, and no-wheel alignment shim on the right side. According to Cessna, the wheel alignment shims are an “as required” item, and no wheel alignment shim would be acceptable. The pre-accident wheel alignment could not be determined due to the separation of the left landing gear. A representative of the Federal Aviation Administration (FAA) traveled to the accident site and reported that the damage was consistent with a ground loop; he was unable to determine the alignment of the main landing gear due to the damage. Examination of the airplane did not reveal any mechanical malfunctions or failures that would have precluded normal operation. The airport’s automated weather observation station reported that, about the time of the accident, wind was from 040° at 4 knots, and no reports of wind gusts. According to the mechanic who performed maintenance on the airplane before the accident flight, he was approached by the pilot’s husband, who reported problems with the airplane’s handling on landings, and wanted different tires and rims installed. The mechanic replaced the tires, wheels, and brake calipers. He indicated that he set the alignment in accordance with the procedures for oversized tires. A review of the maintenance logbook for the airplane revealed that, on October 7, 2021, the main gear axle spindles were aligned, and new ABI-1010 1.25/1/5 wheels with new 8.5-10 6-ply tires and tubes were installed per STC SA017655E. New ABI30-52N brake calipers were installed, and the left tailwheel cable was reinstalled onto the pulley. The elevator and stabilizer movement were checked. STC SA017655E addressed the installation of Alaskan Bushwheel TSO-C26d wheels, part number ABI-1010, as listed in the approved model list (AML) SA017655E. STC SA01015SE addressed the “installation of eligible Alaska Tire and Rubber Company TSO-C62d Tires as listed in the approved model list (AML) SA01015SE. A review of the FAA Approved Model Lists (AML) SA01765SE, and SA01015SE revealed that the Cessna 180H airplane was approved to use the ABI 1010 wheel, and the 8.5-10 6-ply tires and tubes. STC SA01015SE stated in part: Tundra tires reduce the airplane’s directional stability and controllability during takeoff and landing ground rolls, increase its tendency to ground loop during takeoff and landing ground rolls, and increase its tendency to nose over during landings on paved surfaces more than during landings on gravel, grass, or other surfaces that allow the tires to skid more easily. ## Aircraft - Registration: [N926LL](https://openairdocs.org/deregistered/N926LL-2023-05-26), registration cancelled 2023-05-26, S/N 18051470, built 1964 (OpenAirDocs) - Reported make and model: CESSNA 180H - Registry model: [Cessna 180H](https://openairdocs.org/model/cessna-180h) (registry code 2072618) (OpenAirDocs) - Registry engine: [Continental O-470 series](https://openairdocs.org/engine/continental-o-470-series) (registry code 17026, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18051470 - Year built: 1964 - Airframe hours: 5500.1 - Engines: CONT MOTOR O-470 SERIES 230 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Rosemarie Surette - Registered owner: Phillip Surette Rosemarie Surette - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 3, 2021 - Departed: CEG3, Lacombe, OF - Destination: Same as departure - Flight plan: VFR - Airport: GPI, Glacier Park International Airport, runway 02, 9,007 × 150 ft, asphalt - Equipment: Electronic flight bag or handheld device, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 44; injuries: minor; commercial; airplane ratings: single-engine sea, multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review April 4, 2020; seat: left; restraint: 4-point; flight hours: 1,922 total, 294 in this make and model, 1,555 as pilot in command, 79 in the last 90 days, 34 in the last 30 days, 10 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 70° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 46 °F, dew point 18 °F - Altimeter: 30.10 inHg - Observed at: KGPI, 8 nm away - METAR: KGPI 121855Z 08005KT 10SM CLR 08/M08 A3010 RMK AO2 SLP216 T00781078 ## 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 20211012017869A](https://openairdocs.org/incident/20211012017869A), Oct 12, 2021: Cessna 180H, Kalispell, MT, Substantial damage. During landing roll out on runway O2 at Glacier Park International Airport (gpi) N926LL a 1964 Cessna 180H serial number 18051470 swerved to the right and went… ## Other investigations on N926LL (1) 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 ANC20LA100](https://openairdocs.org/ntsb/ANC20LA100), Oct 1, 2020: Cessna 180 (N926LL), Tok, AK, substantial damage. Probable cause: The mechanic’s failure to properly repair the tailwheel, which resulted in a malfunction of the tailwheel and a loss of directional control. ## Docket (9 files) The files NTSB released with the investigation on March 22, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=104134. 8.4 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 3.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15221418&FileExtension=pdf&FileName=NTSB%20Report%206120_1%20for%20Kalispell_Redacted-Rel.pdf - Airframe and engine examination report for WPR22LA016 (item 2, PDF, 10 pages, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15227236&FileExtension=pdf&FileName=Airframe%20and%20Engine%20Examination%20WPR22LA016-Rel.pdf - Pilot's statement (item 3, PDF, 2 pages, 128 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14278488&FileExtension=pdf&FileName=Memo%20for%20Record%20Pilot%27s%20statement-Rel.pdf - Mechanic's statement (item 4, PDF, 2 pages, 117 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14279079&FileExtension=pdf&FileName=Memo%20for%20Record%20Mechanic%27s%20statement-Rel.pdf - Controller in charge statement (item 5, PDF, 1 page, 39 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14670326&FileExtension=pdf&FileName=document10-12-2021-131253-Rel.pdf - FAA STC and aml excerpts (item 6, PDF, 4 pages, 700 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14695537&FileExtension=pdf&FileName=STC%20and%20AML%20Excerpts-Rel.pdf - FAA statement (item 7, PDF, 1 page, 113 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15220103&FileExtension=pdf&FileName=Memo%20for%20Record%20FAA%20statement-Rel.pdf - FAA notes on wreckage (item 8, PDF, 1 page, 108 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15221342&FileExtension=pdf&FileName=FAA%20Notes%20on%20Wreckage_Redacted-Rel.pdf - Airframe logbook excerpt (item 9, PDF, 1 page, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15220113&FileExtension=pdf&FileName=N926LL%20Airframe%20log%20with%20Annual_Redacted-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.