# NTSB WPR20CA053: Cessna 170, N4476B, Missoula, MT, December 28, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: December 28, 2019, 13:45 local (20:45 UTC) - Place: Missoula, MT - Coordinates: 46.915832, -114.089447 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.9158&lon=-114.0894&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: 2 uninjured - Status: Completed, report June 16, 2020 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration FSDO - NTSB case key (mKey): 100746 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR20CA053 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/100746/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=100746 - Page: https://openairdocs.org/ntsb/WPR20CA053 ## Probable cause The pilot receiving instruction's failure to maintain directional control during the takeoff roll, which resulted in a runway excursion and ground-loop, and the flight instructor’s failure to adequately monitor the pilot. ## 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 170B, 74 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=2072306), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Attention/monitoring: monitoring other person](https://openairdocs.org/ntsb-findings/02021535): Personnel issues › Psychological · Instructor/check pilot (probable cause); cases with it: [Cessna 170B, 2 cases](https://openairdocs.org/ntsb-findings/02021535/cases.md?model=2072306), [All aircraft, 200 cases](https://openairdocs.org/ntsb-findings/02021535/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Student/instructed pilot (probable cause); cases with it: [Cessna 170B, 91 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2072306), [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. - [Takeoff: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Cessna 170B, 84 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=2072306), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Takeoff: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Cessna 170B, 13 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=2072306), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Takeoff: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Cessna 170B, 37 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=2072306), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis The pilot, who was receiving instruction for his tailwheel endorsement, reported that, during the takeoff roll, the airplane began to veer left. He applied corrective control inputs, and the flight instructor called for him to abort the takeoff, but the airplane ground looped and departed the runway. The airplane sustained substantial damage to the right wing and aileron. The instructor reported that the event happened too fast for him to correct the diversion and that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. ## Factual narrative The pilot reported that, during the takeoff roll in the tailwheel equipped airplane, it began to veer to the left. He applied corrective control inputs, and the flight instructor called for him to abort the takeoff, but the airplane ground looped as it departed the runway. The airplane sustained substantial damage to the right wing and aileron. Both pilots were flight instructors, and the pilot at the controls was receiving instruction for his tailwheel endorsement. The flight instructor providing instruction stated that the event happened too fast for him to correct the diversion. Neither pilot reported a preaccident mechanical failure or malfunction with the airplane that would have precluded normal operation. ## Aircraft - Registration: [N4476B](https://openairdocs.org/aircraft/N4476B), registered now, S/N 26820, built 1955 (OpenAirDocs) - Reported make and model: Cessna 170 (B) - Registry model: [Cessna 170B](https://openairdocs.org/model/cessna-170b) (registry code 2072306) (OpenAirDocs) - Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 26820 - Year built: 1955 - Airframe hours: 3967.9 - Engines: Continental O-300-A 145 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, December 3, 2019, 4 hours before - Departed: MSO, Missoula, MT - Destination: MSO, Missoula, MT - Airport: MSO, Missoula Intl, runway 12, 9,501 × 150 ft, asphalt - Equipment: Stall warning system, Electronic flight bag or handheld device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 63; injuries: none; commercial, flight instructor, flight engineer; airplane ratings: single-engine land; instrument ratings: helicopter, airplane; medical: class 2, with waivers/limitations; last flight review June 18, 2019; seat: right; restraint: 4-point; flight hours: 2,607 total, 474 in this make and model, 1,708 as pilot in command, 19.8 in the last 90 days, 4.5 in the last 30 days, 0.8 in the last 24 hours - Pilot; age 68; injuries: none; flight instructor, private, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: basicmed; last flight review June 14, 2019; seat: left; restraint: 4-point; flight hours: 1,071.5 total, 2.7 in this make and model, 980.7 as pilot in command, 3.2 in the last 90 days, 0.8 in the last 30 days, 0.8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: 5,000 ft overcast - Temperature: 30 °F, dew point 18 °F - Altimeter: 30.15 inHg ## 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 20191228019919A](https://openairdocs.org/incident/20191228019919A), Dec 28, 2019: Cessna 170B, Missoula, MT, Substantial damage. On December 28, 2019, at 1245 MST, a Cessna 170, N476B4, registered to Montana flying service LLC, ground looped on takeoff at Missoula International Airport,… ## Docket (2 files) The files NTSB released with the investigation on March 17, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=100746. 2.6 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40481216&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Photos (item 2, .PDF, 290 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40481217&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.