# NTSB CEN18LA211: Thrush S2R-H80, N6215P, Parkin, AR, May 31, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 31, 2018, 11:15 local (16:15 UTC) - Place: Parkin, AR - Coordinates: 35.243331, -90.570556 - Nearby events: https://openairdocs.org/map.md?lat=35.2433&lon=-90.5706&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: 1 uninjured - Status: Completed, report April 30, 2019 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA -LIT FSDO - NTSB case key (mKey): 97402 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN18LA211 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/97402/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=97402 - Page: https://openairdocs.org/ntsb/CEN18LA211 ## Probable cause The improper operation of the rudder pedal adjustment mechanism for an undetermined period of time, which led to the failure of the rudder pedal adjustment track, the detachment of the rudder pedal, and the pilot’s subsequent inability to maintain directional control. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Flight control system: rudder control system](https://openairdocs.org/ntsb-findings/01022720): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [All aircraft, 93 cases](https://openairdocs.org/ntsb-findings/01022720/cases.md) - [Flight control system: rudder control system](https://openairdocs.org/ntsb-findings/01022720): Aircraft › Aircraft systems · Incorrect use/operation (probable cause); cases with it: [All aircraft, 93 cases](https://openairdocs.org/ntsb-findings/01022720/cases.md) - [Terrain: sloped/uneven terrain](https://openairdocs.org/ntsb-findings/03021017): Environmental issues › Physical environment · Contributed to outcome; cases with it: [All aircraft, 270 cases](https://openairdocs.org/ntsb-findings/03021017/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Miscellaneous/other](https://openairdocs.org/ntsb-events/900); cases with it: [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) - [Takeoff: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [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: [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) - [Takeoff: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The commercial pilot reported that, during the takeoff roll for the agricultural application flight, the right rudder pedal went full forward against the material hopper and that he subsequently could not maintain directional control of the airplane. The airplane subsequently exited the left side of the runway and struck a ditch. Examination of the airplane revealed that the right rudder pedal had become detached from the rudder pedal adjustment mechanism due to wear on the adjustment track. The Before Starting Engine checklist included a step to adjust and lock the rudder pedals before starting the engine; however, the condition of the rudder system indicated that the airplane had been operated with the rudder pedal forward of the final detent position and against the safety stop rather than in a locked detent position for an undetermined amount of time. The improper adjustment and locking of the rudder pedal adjustment mechanism over time likely led to the excessive wear on the rudder pedal adjustment track, the detachment of the rudder pedal, and the pilot’s subsequent inability to maintain directional control. After the accident, the airplane manufacturer released a service letter detailing the proper use, rigging, and maintenance of the rudder system, including the rudder pedal adjustment mechanism. ## Factual narrative On May 31, 2018, about 1115 central daylight time, a Thrush Aircraft S2R-H80, N6215P, received substantial damage during a runway excursion during takeoff on runway 18 from a private airstrip near Parkin, Arkansas. The pilot was not injured. The aircraft was registered to Mid Continent Aircraft Corp and operated by Air Aids, Inc., under the provisions of Title 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed for the flight, which was operated without a flight plan. The local flight was originating at the time of the accident. The pilot reported that during the takeoff roll the right rudder pedal went all the way forward. Since the airplane was equipped with toe-brakes, once the pedal was all the way forward against the material hopper, he had no way to maintain directional control of the airplane. The pilot attempted to stop the airplane using reverse pitch on the propeller, but the airplane went off the east side of the runway and struck a ditch. Examination of the airplane after the accident revealed that the rudder pedal adjustment mechanism consisted of a track that allowed the rudder pedal shaft to move fore and aft, with a detent pin that engaged holes in the track. The track was equipped with a safety stop bolt to prevent the rudder pedal shaft from travelling too far forward and exiting the end of the track. The track assembly for both the left and right rudder pedal showed wear on the track and the stop bolt installed forward of the most forward detent position. The right adjustment track had a semi-circular section worn completely through that matched the shape of the rudder shaft. This was consistent with the rudder shaft being stopped by the stop bolt rather than being locked in the forward detent position. Determination of how long the rudder system had been used in this manner could not be determined. The "Before Starting Engines" checklist current at the time of the accident contained the instruction "Rudder Pedals – ADJUST and LOCK". Review of the airplane maintenance records showed that the airplane had accumulated 991 hours time in service as of its most recent annual inspection dated December 29, 2017. The airplane manufacturer released a Service Letter, SL-AG-126, on June 11, 2018, entitled "Rudder Pedal Mechanism Inspection", detailing proper use, rigging, and maintenance of the rudder system, including the rudder pedal adjustment mechanism. ## Aircraft - Registration: N6215P (not matched to a registry record) - Reported make and model: THRUSH AIRCRAFT INC S2R-H80 (NO SERIES) - Category: Airplane - Serial number: H80-180DC - Year built: 2016 - Airframe hours: 991 - Engines: GE Aviation Czech H80-100 800 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Air Aids Inc - Registered owner: Mid Continent Aircraft Corp - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, December 29, 2017 - Departed: PVT, Parkin, MO - Destination: PVT, Parkin, MO - Airport: PVT, Private, runway 180, 2,500 × 75 ft, grass/turf - Equipment: Unknown ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 31; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; seat: single; restraint: 4-point; flight hours: 2,900 total, 1,600 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 16 knots, gusting 25 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 91 °F, dew point 70 °F - Altimeter: 29.81 inHg - Observed at: AWM, 20 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 20180531006459A](https://openairdocs.org/incident/20180531006459A), May 31, 2018: Ayres S2R-H80, Parkin, AR, Substantial damage. On may 31, 2018 at approximately 11:15 CST, an ayers, thrush model S2R-H80, serial number H80-180DC, N6215P registered to mid continent aircraft corp, operated… ## Docket (5 files) The files NTSB released with the investigation on November 8, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=97402. 2.1 MB in all. - Pilot Statement (item 1, .PDF, 119 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468141&FileExtension=.PDF&FileName=Pilot%20Statement-Master.PDF - Thrush Service Letter (item 2, .PDF, 715 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468142&FileExtension=.PDF&FileName=Thrush%20Service%20Letter-Master.PDF - Airplane Flight Manual and Maintenance Manual Excerpts (item 3, .PDF, 460 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468143&FileExtension=.PDF&FileName=Airplane%20Flight%20Manual%20and%20Maintenance%20Manual%20Excerpts-Master.PDF - Photo Array (item 4, .PDF, 3 photos, 256 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468144&FileExtension=.PDF&FileName=Photo%20Array-Master.PDF - Annual Inspection Record (item 5, .PDF, 532 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468145&FileExtension=.PDF&FileName=Annual%20Inspection%20Record-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.