Aircraft Accident/Incident Report

Hialeah, Florida 33018
Sunday, August 10, 2003 11:38 EDT

The pilot stated that they departed Opa Locka Airport, Opa Locka, Florida, about 1040. They flew to a practice area to the west of Opa Locka West Airport and performed basic instrument work. The right front seat passenger was acting as the safety pilot. While they were returning to Opa Locka Airport, while in cruise flight at 1,500 feet, the engine ceased operating abruptly. Attempts to restart the engine were unsuccessful and the airplane was ditched in the Everglades, about 2 miles west of the Opa Locka West Airport. Prior to the forced landing they made contact with a controller at the FAA Opa Locka Airport Control Tower. They were rescued by a Miami-Dade County Police Department helicopter and taken back to the Opa Locka Airport. Post accident examination of the airplane and engine after the airplane was recovered from the Everglades showed the engine rotated when the propeller was rotated, but it was determined the accessory section of the engine was not rotating. Disassembly of the engine showed the crankshaft had fractured in the aft cheek of the No. 2 main bearing. The remains of the main bearing were found in the bottom of the engine crankcase. Metallurgical examination of the forward end of the crankshaft revealed that the fracture was located in the aft cheek of the No. 2 main bearing journal. The fracture surface showed features typical of fatigue progression from the radius of the journal in a plane perpendicular to the radius surface (approximately 45 degrees to the journal surface) with multiple origins. The mating fracture surface was completely damaged by rubbing. The fatigue initiation site at the radius surface did not contain scoring marks or scratches, but circumferential skidding marks and rub damage that intersected the origin area were observed elsewhere in the radius. Skidding/rub damage was also observed on the journal surface, with the surface being heat-tinted and rougher than the other main bearing journal surfaces. Examination of the No. 2 main bearing pieces showed that the pieces appeared to make one complete set of bearings. Sections of the bearings were rounded and showed a copper-colored region toward the edge (the copper-colored region is the middle layer in the tri-metal bearings used). The bearing contour matched the crankshaft radius. One bearing piece showed that the anti-rotation tab was fractured off in overstress. Examination of the crankcase halves showed that the No. 2 main bearing bosses revealed severe rotational rub damage, consistent with rotation of the bearing against the boss. Some minor wearing/fretting damage was observed on the boss mating surface of main bearing No. 3. Examination of the cylinder mounting surfaces in the vicinity of the locations where through-bolts at the No. 2 main bearing emerge from the case did not reveal significant fretting/corrosion damage. Only minor localized areas of fretting/corrosion damage were observed. Engine logbook records show that the engine last received a major overhaul on April 1, 1997, 865.5 flight hours before the accident. On November 25, 1998, 557.5 flight hours before the accident, all six cylinders were replaced with new cylinders. On August 23, 2001, 298 flight hours before the accident, all six cylinders were replaced with overhauled cylinders. On March 8, 2003, 31.8 flight hours before the accident, the engine received a 100-hour inspection.

Spinning of the crankshaft No. 2 main bearing for undetermined reasons resulting in damage to the aft cheek of the No. 2 main bearing journal, fatigue failure of the crankshaft cheek, failure of the engine in cruise flight, and damage to the airplane during the subsequent forced landing on unsuitable terrain..