# NTSB CEN18LA070: Cessna 170, N9972A, Ponca City, OK, January 6, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: January 6, 2018, 11:00 local (17:00 UTC) - Place: Ponca City, OK - Coordinates: 36.731945, -97.099723 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.7319&lon=-97.0997&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed, report September 14, 2020 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA - NTSB case key (mKey): 96584 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN18LA070 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/96584/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=96584 - Page: https://openairdocs.org/ntsb/CEN18LA070 ## Probable cause The pilot's loss of directional control during takeoff with a quartering tailwind, which resulted in 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 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; 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) - [Wind: tailwind](https://openairdocs.org/ntsb-findings/03034015): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Cessna 170A, 2 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md?model=2072304), [All aircraft, 594 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: 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) - [Takeoff: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Cessna 170A, 17 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=2072304), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) - [Takeoff: 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 departed with a quartering tailwind in a tailwheel-equipped airplane. During the takeoff roll, the airplane veered left; the pilot reported that he applied rudder to stop the turn, but the airplane continued to veer left. As the airplane exited the left side of the runway, the right main landing gear separated from the airplane, and the fuselage and right wing sustained substantial damage. Examination revealed that the main landing gear fracture surfaces were consistent with an initiating fatigue fracture that propagated toward an overstress fracture; the size of the fatigue crack before the final overstress fracture could not be determined. It is likely that the pilot lost control of the airplane during takeoff in a quartering tailwind. ## Factual narrative On January 6, 2018, about 1100 central standard time, a Cessna 170A airplane, N9972A, was substantially damaged when it was involved in an accident near Ponca City, Oklahoma. The pilot and three passengers were not injured. The airplane was operated by a private individual as a Title 14 Code of Federal Regulations Part 91 personal flight.The pilot stated that prior to takeoff he observed that the windsock indicated a direct crosswind. He began a takeoff roll on runway 35. On takeoff the airplane began to veer left. The pilot added that he applied rudder to correct for the airplane's left turn. However, the airplane continued to veer left and as it approached the side of the runway, the pilot reduced power. As the airplane exited the side of the runway, the right main landing gear separated from the airplane. The airplane came to rest in the grass off the runway surface. Substantial damage was sustained to the fuselage and right wing spar A review of wind conditions, about the time of the accident, found the wind was reported as 100° at 10 knots. The landing gear was photo documented by the Federal Aviation Administration. Photos were examined by the NTSB Materials Laboratory and discovered that the fracture surfaces were consistent with an initiating fatigue fracture which propagated towards an overstress fracture. The pilot reported having over 100 hours in tailwheel equipped airplanes. ## Aircraft - Registration: [N9972A](https://openairdocs.org/aircraft/N9972A), registered now, S/N 19553, built 1950 (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: 19553 - Year built: 1950 - Airframe hours: 3272 - Engines: CONT MOTOR C145 SERIES 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 7, 2017 - Departed: PNC, Ponca City, OK - Destination: WDG, Enid, OK - Airport: PNC, Ponca City Rgnl, runway 35, 7,201 × 150 ft, concrete - Equipment: Onboard weather, Electronic flight bag or handheld device, ADS-B, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 66; injuries: none; commercial, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review July 8, 2017; seat: left; restraint: lap only; flight hours: 3,128 total, 5 in this make and model, 2,951 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 100° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 30 °F, dew point 14 °F - Altimeter: 30.37 inHg - Observed at: KPNC ## 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 20180106000959A](https://openairdocs.org/incident/20180106000959A), Jan 6, 2018: Cessna 170A, Ponca City, OK, Substantial damage. On January 8, 2018, the pilot-command contacted this office to report an accident that occurred on January 6, 2018. Pilot stated that he was departing runway… ## Docket (3 files) The files NTSB released with the investigation on July 1, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=96584. 3.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485042&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Engineering Exam (item 2, .PDF, 806 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485043&FileExtension=.PDF&FileName=Engineering%20Exam-Master.PDF - Wind Components (item 3, .PDF, 197 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485044&FileExtension=.PDF&FileName=Wind%20Components-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.