On August 8, 1998, a Dean R. Fellows VANS RV-6 (registration N245DF) was involved in an aviation accident near Bainbridge, GA. Investigators recorded the probable cause as: The pilot's failure to properly modify the crankshaft per the manufacturers service instructions for installation of a fixed pitch propeller and to apply proper torque values to the propellers mounting bolts. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot reported a vibration and subsequent oil leak that obscured forward vision, leading to an emergency landing. Examination found improperly torqued propeller bolts and an unmodified crankshaft.
Incident Details
During cruise flight, the pilot experienced a vibration in the airplane. After checking the instruments, the pilot decided to continue toward the destination. Approximately five minutes later, oil began leaking from the front of the engine and blew onto the windshield, obscuring the pilot's forward vision. The pilot subsequently performed an emergency landing, during which the airplane sustained damage.
Examination Findings
Post-incident examination of the wooden propeller assembly revealed that the bolts were not properly torqued. Additionally, it was found that the crankshaft had not been modified in accordance with the manufacturer's service instructions.