NTSB Identification: CHI01LA252.
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Accident occurred Saturday, July 28, 2001 in Edmore, ND
Probable Cause Approval Date: 01/23/2002
Aircraft: Air Tractor AT-301, registration: N4361S
Injuries: 1 Minor.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
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.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: 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 Full narrative available
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