Aviation Accident Summaries

Aviation Accident Summary MIA05LA081

Panama City, FL, USA

Aircraft #1

N231SK

Beech C-45H

Analysis

The pilot stated that the approach to Panama City-Bay County International Airport was uneventful. He lowered the landing gear and observed "3 in the green" and complied with the landing checklist. He reported a normal touchdown with full flaps, and applied moderate reverse thrust with very light brakes. Approximately halfway through rollout, the tower informed him of smoke from his left main gear. About 1 second later, the left wing "dipped" about a foot. Seconds later, the left gear collapsed, the propeller contacted the runway, and the airplane rotated to the left about 70 degrees, coming to rest upright on runway 23. Examination of the left main landing gear cylinder top brace assembly (P/N 404-188406) by the NTSB Materials Laboratory revealed evidence of overstress on all fracture surfaces.

Factual Information

On March 18, 2005, about 0650 central standard time, a Beech C-45H, N231SK, registered and operated by Jim Hankins Air Service, Inc., experienced collapse of the left main landing gear during the landing roll at Panama City-Bay County International Airport, Panama City, Florida. Visual meteorological conditions prevailed at the time and an instrument flight rules flight plan was filed for the 14 CFR Part 135 non-scheduled, domestic, cargo flight from Southwest Georgia Regional Airport, Albany, Georgia, to Panama City-Bay County International Airport. The airplane was substantially damaged and the commercial-rated pilot, the sole occupant, was not injured. The flight originated about 0505, from Southwest Georgia Regional Airport. The pilot stated that the approach to Panama City-Bay County International Airport was uneventful. He lowered the landing gear and observed "3 in the green" and complied with the landing checklist. He reported a normal touchdown with full flaps, and applied moderate reverse thrust with very light brakes. Approximately halfway through rollout, the tower informed him of smoke from his left main gear. About 1 second later, the left wing "dipped" about a foot. Seconds later, the left gear collapsed, the propeller contacted the runway, and the airplane rotated to the left about 70 degrees, coming to rest upright on runway 23. Postaccident examination of the airplane revealed the left main landing gear cylinder top brace assembly (P/N 404-188406), was fractured. Examination of the left main landing gear cylinder top brace assembly (P/N 404-188406) by the NTSB Materials Laboratory, located in Washington, D.C., revealed the top aft tube and lower angled tube were fractured at or near the cylinder attachment points; whereas, the top forward tube was fractured at the left-most welds where the brace connects to the aircraft structure. Optical examination of all of the fracture surfaces of the welds revealed shear lips and rough fracture features consistent with tensile/shear overstress. Scanning electron microscope (SEM) examination of all fracture surface regions in the welds revealed ductile dimples, confirming overstress fracture. The other two fractures in the tubes propagated on 45 degree slant planes with features consistent with overstress. The airplane minus the retained top brace assembly was released to Guy P. Owen, Director of Maintenance for Jim Hankins Air Service, Inc, on April 2, 2005. The retained top brace assembly was also released to Guy P. Owen, on July 12, 2005.

Probable Cause and Findings

The overload failure of the left main landing gear for undetermined reasons during the landing roll resullting in collapse of the left main landing gear.

 

Source: NTSB Aviation Accident Database

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