Sunday, May 28, 2017

Beech 58 Baron, N25734: Accident occurred October 06, 2015 at Southwest Georgia Regional Airport (KABY), Albany, Dougherty County, Georgia

Aviation Accident Final Report - National Transportation Safety Board:

Investigation Docket - National Transportation Safety Board:

Aviation Accident Data Summary - National Transportation Safety Board:

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity:

Federal Aviation Administration / Flight Standards District Office; Atlanta, Georgia

RCL Farms Leasing LLC:

NTSB Identification: ERA16LA004
14 CFR Part 91: General Aviation
Accident occurred Tuesday, October 06, 2015 in Albany, GA
Probable Cause Approval Date: 05/01/2017
Aircraft: BEECH 58, registration: N25734
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

While taxiing from the runway after landing, the commercial pilot noted "softness" when he applied the left brake. Upon entering the ramp area, he further applied the brakes and attempted to slow the airplane; however, the brakes had no effect. The airplane rolled off the ramp, into the grass, and impacted an airport perimeter fence.

Examination of both left and right main landing gear brake torque plates revealed that they had fractured in fatigue, and that the fatigue cracks emanated from corrosion pitting within the attachment bolt holes. The corrosion pits in the attachment bolt holes were stress risers that likely reduced the strength of the plates. It is likely that, during the most recent maintenance inspection, about 7 months before the accident, the mechanic failed to thoroughly inspect the brake system as required, which would have detected the corrosion and fatigue cracks prior to their ultimate failure.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
The mechanic's inadequate inspection of the brake system during the most recent annual inspection, which resulted in the failure of both left and right main landing gear torque plates and a subsequent loss of braking action.

On October 6, 2015, about 1900 eastern daylight time, a Beech 58, N25734, sustained substantial damage when it impacted a fence while taxiing at Southwest Georgia Regional Airport (ABY), Albany, Georgia. The commercial pilot was not injured. Day visual meteorological conditions prevailed and no flight plan was filed for the local personal flight, which was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. The flight originated from Dawson Municipal Airport (16J), Dawson, Georgia, around 1830.

According to the pilot, the flight was uneventful. Then, while taxiing from the runway, the pilot noted "softness" when he applied the left brake. Upon entering the ramp area, he applied the brakes and attempted to slow the airplane; however, the brakes had no effect. The airplane rolled into a grass area and impacted an airport perimeter fence.

According to Federal Aviation Administration records, the airplane, manufactured in 1973, was registered to a corporation in 2012. It was equipped with two Continental Motors IO-520 series, 285-hp engines. According to airplane maintenance logbooks, the most recent annual inspection was completed on March 9, 2015, and at that time, the airplane had accumulated 1,145.7 hours in-service. The maintenance log entry for the annual inspection stated that it was performed in accordance with the manufacturer guidance and the main landing gear brake linings were replaced. According to the manufacturer's guidance, item number 28 for the 100-hour inspection, stated "BRAKES – Check for condition and wear, ease of operation and proper release of the parking brake. Check for unusual brake chatter."

A postaccident examination of the airplane revealed substantial damage to the left wing. At the time of the accident, the Hobbs meter indicated 1214.8 hours. In addition, the brakes were examined and there was a trace amount of hydraulic fluid in both of the brake reservoirs. Hydraulic fluid was also noted on the surface of the left wheel torque plate. Furthermore, the left wheel torque plate assembly exhibited several fractures and the fitting tube was bent. The right wheel torque plate exhibited fractures as well, and one bolt was absent from the torque plate.

The main wheel torque plates and an attachment bolt from the right wheel plate were removed from the airplane and sent to the NTSB Materials laboratory for further examination. Both plates were fractured into multiple pieces and each plate contained several bolt holes, which were intersected by a fracture. Bench binocular microscope examination of each plate revealed crack arrest marks typical of fatigue cracking emanated from several bolt holes. Furthermore, the fatigue crack regions exhibited a black tint consistent with oxidation in ferrous metal. The fatigue crack terminated and regions outside the fatigue crack exhibited a rough granular texture consistent with overstress separation.

The attachment bolt from the right wheel plate was fractured on a slant plane and contained fracture features typical of overstress separation.

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