Wednesday, July 13, 2016

Canadian Car & Foundry Harvard MK IV, N99CV: Accident occurred July 11, 2016 in Somerset, Pulaski County, Kentucky

Aviation Accident Final Report - National Transportation Safety Board:

Docket And Docket Items -   National Transportation Safety Board:

FAA Flight Standards District Office: FAA Louisville FSDO-17 

NTSB Identification: GAA16CA373
14 CFR Part 91: General Aviation
Accident occurred Monday, July 11, 2016 in Somerset, KY
Probable Cause Approval Date: 12/05/2016
Aircraft: CANADIAN CAR & FOUNDRY HARVARD, registration: N99CV
Injuries: 2 Uninjured.

NTSB investigators used data provided by various entities, including, but not limited to, the Federal Aviation Administration and/or the operator and did not travel in support of this investigation to prepare this aircraft accident report.

The pilot of the tailwheel equipped airplane reported that during the landing roll, and after the tail wheel touched down, the airplane swerved to the right, then to the left, and veered off the runway to the right and impacted an airport sign. 

The airplane sustained substantial damage to the right aileron.

Following a postaccident examination of the right/left main landing gear wheel, the pilot sent an email to the Federal Aviation Administration (FAA) Inspector, regarding the Timken bearing for the main landing gear wheel, this email stated in part: "The bearing itself is a stock Timken 18200 bearing, nothing special. While jacked up the wheel turns fine by hand. And this is unlike any failed bearing I've seen. And getting close to a CND (cannot duplicate) condition. I think it is possible the bearing was in the process of failing. At touchdown speeds (approximately 60-80 knots) with little weight on wheels the bearing could lock up or freeze momentarily causing the aircraft to veer right".

A photo of the Timken 18200 tapered roller bearing was sent to the manufacturer for further examination. The manufacturer examined the photo and concluded that there was no evidence of damage or scoring, and further reported that if the bearing would have seized, he would have expected to see damage to the rolling contact surfaces.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:

The pilot's failure to maintain directional control during the landing roll, which resulted in runway excursion, and collision with an airport sign.

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