# NTSB CHI01LA252: Air Tractor AT-301, N4361S, Edmore, ND, July 28, 2001 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: July 28, 2001, 15:00 local (20:00 UTC) - Place: Edmore, ND - Coordinates: 48.409763, -98.450248 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=48.4098&lon=-98.4502&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report January 23, 2002 - Report: Approved by Office Director - Parties: FAA-Fargo, North Dakota FSDO - NTSB case key (mKey): 53272 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI01LA252 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/53272/pdf - Page: https://openairdocs.org/ntsb/CHI01LA252 ## Probable cause The incorrect installation of the wheel assembly bolts by maintenance personnel resulting in the stripped bolt threads and ultimate failure of the wheel, and directional control not possible by the pilot. A factor was the ditch ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, takeoff - roll/run - miscellaneous,bolt/nut/fastener/clamp/spring - stripped thread (cause) - maintenance,installation - incorrect, other maintenance personnel (cause) - miscellaneous,bolt/nut/fastener/clamp/spring - unapproved part - landing gear,wheel - failure (cause) - Loss of control - on ground/water, takeoff - roll/run - directional control - not possible, pilot in command (cause) - On ground/water encounter with terrain/water, takeoff - roll/run - terrain condition - ditch (contributing factor) - Nose over, takeoff - roll/run ## Analysis The airplane impacted a ditch and nosed over during takeoff from a road. Examination of the wreckage revealed that the right outboard wheel half, right tire, and right tire inner tube had separated from the airframe. No other anomalies were found that could be associated with a pre-impact condition. Three of the right wheel through bolts were recovered from the accident scene. Two of the recovered bolts had stripped threads and a third was fractured in the threaded portion of the bolt. The left wheel was examined and was found intact. Seven of the through bolts that hold the left wheel halves together were found to have been over-torqued. The torque readings were from 125 to 175 inch-pounds on these bolts. The specified torque as printed on the wheel is 90 inch-pounds. The remaining two bolts were found to be stripped. One of the through bolts was found to be a coarse thread bolt. The bolts specified for attaching the wheel halves are AN4 fine thread bolts. ## Factual narrative On July 28, 2001, at about 1500 central daylight time, an Air Tractor AT-301, N4361S, piloted by a commercial pilot, was substantially damaged when it impacted a ditch and nosed over during takeoff from a road near Edmore, North Dakota. The 14 CFR Part 137 Aerial application flight was operating in visual meteorological conditions and was not on a flight plan. The pilot received minor injuries. The local flight was originating at the time of the accident. Post accident examination of the wreckage revealed that the right outboard wheel half, right tire, and right tire inner tube had separated from the airframe. No other anomalies were found that could be associated with a pre-impact condition. Three of the right wheel through bolts were recovered from the accident scene. Two of the recovered bolts had stripped threads and the third was fractured in the threaded portion of the bolt. The left wheel was examined and was found intact. Seven of the through bolts that hold the left wheel halves together were found to have been over-torqued. The torque readings were from 125 to 175 inch-pounds on these bolts. The specified torque as printed on the wheel is 90 inch-pounds. The remaining two bolts were found to be stripped. One of the through bolts was found to be a coarse thread bolt. The bolts specified for attaching the wheel halves are AN4 fine thread bolts. ## Aircraft - Registration: [N4361S](https://openairdocs.org/deregistered/N4361S-2006-01-27), registration cancelled 2006-01-27, S/N 301-0041 (OpenAirDocs) - Reported make and model: Air Tractor AT-301 - Registry model: [Air Tractor AT-301](https://openairdocs.org/model/air-tractor-at-301) (registry code 0390103) (OpenAirDocs) - Category: Airplane - Serial number: 301-0041 - Airframe hours: 5000 - Engines: P&W R-1340-AN1 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Mark D. Brekke - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, May 20, 2001, 310 hours before - Departed: Edmore, ND ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; injuries: minor; commercial; airplane ratings: single-engine land, single-engine sea; medical: class 2, valid medical--w/ waivers/lim; last flight review May 5, 2000; seat: center; flight hours: 3,010 total, 900 in this make and model, 3,010 as pilot in command, 360 in the last 90 days, 250 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 140° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 77 °F, dew point 61 °F - Altimeter: 30.01 inHg - Observed at: DVL, 25 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 20010728021479A](https://openairdocs.org/incident/20010728021479A), Jul 28, 2001: Airtrc AT301, Devils Lake, ND, No damage. (-23) On July 28, 2001 at 1500 local time, an air tractor AT-301 owned by brekke aerial service, lost the right wheel on takeoff for a CFR 137 flight. VMC… 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.