# NTSB GAA16CA419: Cessna 172, N734GM, Lewiston, MT, August 2, 2016 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: August 2, 2016, 16:30 local (22:30 UTC) - Place: Lewiston, MT - Coordinates: 47.116943, -109.376388 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.1169&lon=-109.3764&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report January 18, 2017 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 93775 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA16CA419 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/93775/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=93775 - Page: https://openairdocs.org/ntsb/GAA16CA419 ## Probable cause The pilot's failure to ensure that his seat was adjusted and locked, which resulted in his seat sliding aft during the takeoff roll, and the subsequent loss of directional control and runway excursion. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Fuselage: seat/cargo attach fitting](https://openairdocs.org/ntsb-findings/01035347): Aircraft › Aircraft structures · Incorrect use/operation (probable cause); cases with it: [Cessna 172N, 3 cases](https://openairdocs.org/ntsb-findings/01035347/cases.md?model=2072434), [All aircraft, 27 cases](https://openairdocs.org/ntsb-findings/01035347/cases.md) - [Use of equip/info: use of equip/system](https://openairdocs.org/ntsb-findings/02063015): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Cessna 172N, 10 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md?model=2072434), [All aircraft, 1,391 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md) - [Use of equip/info: use of checklist](https://openairdocs.org/ntsb-findings/02063030): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Cessna 172N, 3 cases](https://openairdocs.org/ntsb-findings/02063030/cases.md?model=2072434), [All aircraft, 336 cases](https://openairdocs.org/ntsb-findings/02063030/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 172N, 150 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2072434), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [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 172N, 82 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=2072434), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Object/animal/substance: fence/fence post](https://openairdocs.org/ntsb-findings/03022047): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Cessna 172N, 5 cases](https://openairdocs.org/ntsb-findings/03022047/cases.md?model=2072434), [All aircraft, 313 cases](https://openairdocs.org/ntsb-findings/03022047/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) (defining event); cases with it: [Cessna 172N, 18 cases](https://openairdocs.org/ntsb-events/490/sequence.md?model=2072434), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md) - [Takeoff: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [Cessna 172N, 81 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=2072434), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) ## Analysis According to the pilot, during the takeoff roll about 30 knots indicated airspeed, his seat slid back a few inches. He reported that, "The slight movement of the pilot seat aft during takeoff roll was inconvenient. Had I done nothing at this point, it most likely would have been a manageable situation." However, the pilot reported that, "My reaction to move the seat forward using the adjustment bar during takeoff roll acceleration is what caused the pilot seat to move to the full aft position." He reported that the full aft seat movement caused him to pull back on the yoke, the nose landing gear came off the ground, and the airplane veered left and exited the runway to the left, and struck a fence before coming to a halt. The airplane sustained substantial damage to both wings, horizontal stabilizer, and elevator. The pilot reported that there were no mechanical malfunctions or anomalies with the airplane during the takeoff roll that would have prevented normal flight operations. Federal Aviation Administration Aviation Safety Inspector's examined the pilot's seat, track and adjustment assembly and found that there were no failures or anomalies. According to the manufacturer's Pilot Operating Handbook, item number three of the Before Start Checklist states: Seats/Belts –Adjusted and locked ## Factual narrative According to the pilot, during the takeoff roll about 30 knots indicated airspeed, his seat slid back a few inches. He reported that, "The slight movement of the pilot seat aft during takeoff roll was inconvenient. Had I done nothing at this point, it most likely would have been a manageable situation." However, the pilot reported that, "My reaction to move the seat forward using the adjustment bar during takeoff roll acceleration is what caused the pilot seat to move to the full aft position." He reported that the full aft seat movement caused him to pull back on the yoke, the nose landing gear came off the ground, and the airplane veered left and exited the runway to the left, and struck a fence before coming to a halt. The airplane sustained substantial damage to both wings, horizontal stabilizer, and elevator. The pilot reported that there were no mechanical malfunctions or anomalies with the airplane during the takeoff roll that would have prevented normal flight operations. Federal Aviation Administration Aviation Safety Inspector's examined the pilot's seat, track and adjustment assembly and found that there were no failures or anomalies. According to the manufacturer's Pilot Operating Handbook, item number three of the Before Start Checklist states: Seats/Belts –Adjusted and locked ## Aircraft - Registration: [N734GM](https://openairdocs.org/deregistered/N734GM-2018-05-31), registration cancelled 2018-05-31, S/N 17268843, built 1977 (OpenAirDocs) - Reported make and model: CESSNA 172 (N) - Registry model: [Cessna 172N](https://openairdocs.org/model/cessna-172n) (registry code 2072434) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17268843 - Year built: 1977 - Airframe hours: 5970.2 - Engines: LYCOMING 0-360-A4M 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Wheels Down LLC - Registered owner: Wheels Down LLC - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, January 19, 2016 - Departed: MT56, Lewistown, MT - Destination: BZM, Bozeman, MT - Airport: MT65, Smithfield, runway 24, 2,646 × 50 ft, asphalt - Equipment: ADS-B, Stall warning system, Electronic flight bag or handheld device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: none; commercial; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review October 21, 2015; seat: left; restraint: 3-point; flight hours: 1,132 total, 247 in this make and model, 878 as pilot in command, 12 in the last 90 days, 2 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 90° at 13 knots, gusting 18 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 91 °F, dew point 52 °F - Altimeter: 29.96 inHg - Observed at: KLWT, 5 nm away ## 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 20160802012979A](https://openairdocs.org/incident/20160802012979A), Aug 2, 2016: Cessna 172N, Lewistown, MT, Substantial damage. On June 12, 2016 at approximately 1630 MDT (2230Z) a Cessna 172N sustained substantial damage to the propeller, left aileron, both wing struts, empennage and… ## Docket (3 files) The files NTSB released with the investigation on November 10, 2016, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=93775. 1.0 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 267 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40459015&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - FAA Inspector's Statement (item 2, .PDF, 111 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40446340&FileExtension=.PDF&FileName=FAA%20Inspector%27s%20Statement-Master.PDF - Photos (item 3, .PDF, 668 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40446341&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.