# NTSB WPR23LA096: Cessna 170, N9534A, Mesa, AZ, January 23, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: January 23, 2023, 16:30 local (23:30 UTC) - Place: Mesa, AZ · KIWA - Coordinates: 33.31, -111.66 - Nearby events: https://openairdocs.org/map.md?lat=33.3100&lon=-111.6600&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA - NTSB case key (mKey): 106627 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR23LA096 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/106627/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=106627 - Page: https://openairdocs.org/ntsb/WPR23LA096 ## Probable cause The pilot’s failure to maintain directional control during the landing roll out and the preexisting fatigue cracks in the left main landing gear leg, which resulted in the leg’s premature overstress fracture during the ground loop. ## 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 170A, 23 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=2072304), [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 170A, 33 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2072304), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Landing gear system: main landing gear](https://openairdocs.org/ntsb-findings/01023210): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Cessna 170A, 4 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=2072304), [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 170A, 4 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=2072304), [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: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Cessna 170A, 33 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=2072304), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Cessna 170A, 11 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2072304), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The pilot receiving instruction was conducting takeoffs and landings to regain tailwheel currency. During the second landing’s roll out, the airplane began to veer left of the runway centerline. The pilot applied correction with right rudder; however, he overcorrected and the airplane veered to the right. The pilot and the flight instructor both applied left rudder and brake to counteract the veer to the right. However, the veer to the right developed into a ground loop and the left main landing gear leg fractured. The airplane dropped onto the fractured end of the landing gear leg and came to rest upright. A metallurgical examination of the fractured landing gear leg revealed small fatigue cracks along the radius of the brake line retainer clip bore and outboard face. These small fatigue cracks concentrated stress in the radius, facilitating a premature overstress fracture due to the stresses on the part during the landing. ## Factual narrative On January 23, 2023, about 1630 mountain standard time, a Cessna 170A, N9534A, sustained substantial damage when it was involved in an accident near Mesa, Arizona. The pilot, flight instructor, and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. According to the pilot receiving instruction, he was conducting takeoffs and landings to regain tailwheel currency. During the landing roll after the second landing, the airplane began to veer to the left. He applied correction with right rudder; however, he overcorrected and the airplane veered to the right. The pilot receiving instruction and the flight instructor both applied left rudder and brake to counteract the veer to the right. Despite their corrections, the airplane ground looped to the right. During the ground loop, the left main landing gear leg fractured mid span, near the brake line retainer clip bore, and the left wing contacted the runway surface. Postaccident examination and fracture analysis of the left main landing gear leg was conducted by the National Transportation Safety Board Materials Laboratory. The examination revealed that the landing gear failed in its final landing due to small fatigue cracks present along the radius of the retainer clip bore and the outboard face. Outside the fatigue cracks, the fracture surface exhibited features consistent with overstress fracture. The fatigue cracks initiated at small corrosion pits along the radius of the bore, and propagated until the final landing, when the remainder of the leg fractured from overstress. ## Aircraft - Registration: [N9534A](https://openairdocs.org/aircraft/N9534A), registered now, S/N 19095, built 1949 (OpenAirDocs) - Reported make and model: CESSNA 170 (A) - Registry model: [Cessna 170A](https://openairdocs.org/model/cessna-170a) (registry code 2072304) (OpenAirDocs) - Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 19095 - Year built: 1949 - Airframe hours: 4102 - Engines: Continental O-300-D 145 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 10, 2022, 38 hours before - Airport: KIWA, Phoenix-Mesa Gateway, runway 12L, 9,300 × 150 ft, concrete - Equipment: Handheld GPS, Electronic flight bag or handheld device, ADS-B, Stall warning system, Onboard weather ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 70; injuries: none; airline transport, commercial; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review January 21, 2023; seat: left; restraint: 3-point; flight hours: 17,654 total, 1 in this make and model, 16,556 as pilot in command, 6 in the last 90 days, 2 in the last 30 days - Flight instructor; age 69; injuries: none; airline transport, commercial, flight instructor; airplane ratings: single-engine land, multi-engine land, single-engine sea, multi-engine sea; instrument ratings: helicopter; medical: class 1, with waivers/limitations; last flight review November 16, 2022; seat: right; restraint: 3-point; flight hours: 27,000 total, 27 in this make and model, 20,000 as pilot in command, 41 in the last 90 days, 15 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 240° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: 7,000 ft broken - Temperature: 46 °F, dew point 18 °F - Altimeter: 29.98 inHg - Observed at: KIWA - METAR: SPECI KIWA 232331Z 24003KT 10SM BKN070 BKN085 08/M08 A2998 RMK ACFT MSHP ## 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 20230123004799A](https://openairdocs.org/incident/20230123004799A), Jan 23, 2023: Cessna 170A, Mesa, AZ, Substantial damage. Airman had just recently completed the flight review. He also wanted to obtain currency in a tail wheel aircraft after a 6 year span. He coordinated with a… ## Other investigations on N9534A (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 MIA94LA133](https://openairdocs.org/ntsb/MIA94LA133), May 6, 1994: Cessna 170A (N9534A), Boca Raton, FL, substantial damage. Probable cause: THE FAILURE OF THE PILOT TO MAINTAIN DIRECTIONAL CONTROL. ## Docket (4 files) The files NTSB released with the investigation on May 9, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=106627. 11.2 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 4.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15121384&FileExtension=pdf&FileName=WPR23LA096_6120_flat_Redacted-Rel.pdf - Memorandum for record a�� pilot receiving instruction (item 2, PDF, 2 pages, 110 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16745927&FileExtension=pdf&FileName=Louis%20Hudgin%20Statement%20Memorandum%20of%20Record_Redacted-Rel.pdf - Photo array (item 3, PDF, 2 pages, 877 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16462714&FileExtension=pdf&FileName=WPR23LA096_508-Rel.pdf - Materials laboratory factual report (item 4, PDF, 20 pages, 24 photos, 6.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15928884&FileExtension=pdf&FileName=23-059%20-%20Materials%20Lab%20Factual%20Report%20(WPR23LA096)-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.