# NTSB CEN23LA425: Air Tractor AT-802, N445HA, Herington, KS, September 28, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: September 28, 2023, 11:30 local (16:30 UTC) - Place: Herington, KS - Coordinates: 38.691478, -96.806933 - Nearby events: https://openairdocs.org/map.md?lat=38.6915&lon=-96.8069&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Air Tractor, Federal Aviation Administration - SAIBs cited in the narratives: [SAIB 2024-03](https://openairdocs.org/saib/2024-03) (OpenAirDocs) - NTSB case key (mKey): 193176 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN23LA425 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/193176/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=193176 - Page: https://openairdocs.org/ntsb/CEN23LA425 ## Probable cause The design of the spray valve control lever, which restricted the range of the left rear rudder and brake pedal and resulted in a loss of control during landing. ## 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 · Design (probable cause); cases with it: [Air Tractor AT-802, 1 case](https://openairdocs.org/ntsb-findings/01022720/cases.md?model=0390305), [All aircraft, 93 cases](https://openairdocs.org/ntsb-findings/01022720/cases.md) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Air Tractor AT-802, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=0390305), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Air Tractor AT-802, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=0390305), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Air Tractor AT-802, 2 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=0390305), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis The flight instructor in the rear seat reported that during the landing roll the tailwheel unlocked, and the airplane turned right. He applied full left rudder and attempted to apply left brake, but when the left rudder and left brake were both applied, the top of the pedal toe brake contacted the spray control lever pushrod, preventing full braking. The airplane continued off the right side of the runway, where the airplane impacted a ditch and sustained substantial damage to the wings. Postaccident examination revealed that the front-seat rudder/brake pedals were found to move to their full range of motion without interference. The rear-seat rudder/brake pedals were found in the forward adjustment position. With full left rudder deflection, the left brake pedal’s range was restricted by the upper spray valve control pushrod. There were no other mechanical malfunctions or failures with the airplane that would have precluded normal operation. The design of the spray valve control lever and left rear rudder pedal in the forward adjustment position restricted the left rudder and brake pedal, which resulted in a loss of control during landing. ## Factual narrative On September 28, 2023, about 1130 central daylight time, an Air Tractor AT-802 airplane, N445HA, was substantially damaged when it was involved in an accident at Herington Regional Airport (HRU), Herington, Kansas. The flight instructor and pilot receiving instruction were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor, who was in the rear seat, stated that during landing as they slowed to 35 to 40 mph, the tailwheel unlocked, and the airplane turned right. The flight instructor applied full left rudder and attempted to apply the left toe brake, but the brake pedal was restricted from moving forward. When left rudder and left brake were applied, the top of the pedal contacted the spray control lever pushrod and full brake could not be applied. The airplane continued off the right side of the runway. The airplane impacted a ditch, which resulted in substantial damage to the wings. Postaccident examination revealed that the front-seat rudder/brake pedals could move through their full range of motion without interference. The rear-seat rudder/brake pedals were found in the forward adjustment position. With the rear pedals in the forward position, the left rear brake pedal range was restricted by the upper spray valve control pushrod, preventing the application of full left brake from the rear seat. There were no other mechanical malfunctions or failures with the airplane that would have precluded normal operation. The upper spray valve push rod was installed in the airframe by Air Tractor during the original production of the airplane. Air Tractor reported that there were 94 other airplanes affected by this design installation. As result of this investigation, on December 29, 2023, Air Tractor completed service letter (SL) 405, which was applicable to certain AT-802 airplanes with a spray valve control lever installed. The SL was issued due to the spray valve control valve pushrod’s interference with the left rear rudder pedal, which reduced controllability and could lead to an accident. The interference was only possible when the left rear rudder pedal is in the forward adjustment position (Figure 1). This interference prevents simultaneous application of full left rudder and left brake when operated from the rear seat. This control restriction could lead to a loss of control causing significant injury and aircraft damage. Placement of the rear rudder pedals in the rear adjustment position is a temporary solution that will allow full, simultaneous application of left rudder and left brake. Figure 1. Air Tractor photo and labels of the rudder pedal restriction with spray valve control lever pushrod (Courtesy of Air Tractor SL 405). As result of this investigation, on April 25, 2024, the Federal Aviation Administration issued special airworthiness information bulletin (SAIB) 2024-03, “Rudder Control System,” which recommended that all affected operators modify therear cockpit rudder pedal adjustment in accordance with Air Tractor, Inc. Service Letter 405. ## Aircraft - Registration: [N445HA](https://openairdocs.org/aircraft/N445HA), registered now, S/N 802-0633, built 2016 (OpenAirDocs) - Reported make and model: AIR TRACTOR INC AT-802 - Registry model: [Air Tractor AT-802](https://openairdocs.org/model/air-tractor-at-802) (registry code 0390305) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PT6A-67F](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-67f) (registry code 52290, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 802-0633 - Year built: 2016 - Airframe hours: 3360.3 - Engines: Pratt & Whitney PT6-65AG 1220 horsepower turbo prop - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Moor Halley Ray Jr - Airworthiness certificate: Special, Restricted (Special) - Destination: Same as departure - Airport: HRU, Herington Rgnl, runway 35, 4,184 × 75 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 58; injuries: none; commercial, flight instructor; airplane ratings: single-engine sea, multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review April 13, 2023; seat: rear; restraint: 4-point; flight hours: 25,000 total, 4,500 in this make and model, 25,000 as pilot in command, 400 in the last 90 days, 60 in the last 30 days, 3 in the last 24 hours - Pilot; age 38; injuries: none; commercial, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, unknown; seat: front ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 88 °F, dew point 59 °F - Altimeter: 29.94 inHg - Observed at: KMHK, 27 nm away - METAR: KMHK 281652Z 19007KT 10SM CLR 31/15 A2994 RMK AO2 SLP127 T03060150 ## 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 20230928017619A](https://openairdocs.org/incident/20230928017619A), Sep 28, 2023: Air Tractor Inc AT-802, Herington, KS, Substantial damage. On 9/28/2023 approximately 11:30 am local time at the Herington Regional Airport (hru). The Air tractor AT-802 was conducting a landing at hru on runway 35… ## Docket (8 files) The files NTSB released with the investigation on November 7, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=193176. 16.2 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 10.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17259388&FileExtension=pdf&FileName=6120%20-%20CFI_Redacted-Rel.pdf - Reports from parties to the investigation - air tractor (item 2, PDF, 6 pages, 556 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17259462&FileExtension=pdf&FileName=AT%20exam%20-%20all_Redacted-Rel.pdf - NTSB examination summary (item 3, PDF, 5 pages, 130 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17258953&FileExtension=pdf&FileName=CEN23LA425%20Flight%20Controls%20Examination%20Report-Rel.pdf - Photos (item 4, PDF, 10 pages, 9 photos, 4.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17260028&FileExtension=pdf&FileName=Photos-Rel.pdf - Air tractor service letter #405 - controls interference (item 5, PDF, 3 pages, 556 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17258828&FileExtension=pdf&FileName=SL405-Rel.pdf - FAA SAIB 2024-03 - rudder control system (item 6, PDF, 1 page, 175 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17259037&FileExtension=pdf&FileName=FAA%20SAIB%202024-03%20(Air%20Tractor%20rudder%20pedal)-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 7, PDF, 1 page, 121 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17258963&FileExtension=pdf&FileName=Wreckage%20Release%20Form%20-%20signed_Redacted-Rel.pdf - Statement of party representatives to NTSB investigation (item 8, PDF, 1 page, 321 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17259418&FileExtension=pdf&FileName=Party%20form%20-%20Air%20Tractor_Redacted-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.