ATL01LA095

Less than two hours into the flight, the engine lost power during cruise. During emergency descent, the airplane struck power lines and a tree, then collided with the ground. Examination of the engine accessory case revealed the idler gear was fractured, and the two attachment holes in the crank case for the idler gear shaft assembly were elongated. Three fractured teeth from the idler gear and two separated bolt heads were recovered. The fracture surface of each gear tooth displayed crack arrest marks and a rough surface consist with high-stress, low-cycle fatigue. The shanks below each separated bolt head were worn to about one-third their original diameter. The engine received a zero-time equivalent overhaul on May 9, 1985, and operated 1371 hours since the overhaul. Textron Lycoming Service Instruction No. 1009AQ states the recommended time between overhaul periods for the engine is 2000 hours. The Lycoming parts catalog for the engine specifies a bolt is required to attach the idler gear shaft assembly at one attachment hole, and a slotted nut and stud are required to attach the idler gear shaft assembly at the other attachment hole.

On August 26, 2001, at 0956 eastern daylight time, a Piper PA-32-300, N2116G, registered to King Champ Aviation, Inc., and operated by the private pilot, struck power lines and a tree during an emergency landing following a loss of engine power in Homerville, Georgia. The personal flight was operated under the provisions of Title 14 CFR Part 91 with an instrument flight plan filed. Visual meteorological conditions prevailed. The pilot and passenger were not injured, and the airplane sustained substantial damage. The flight departed Kissimmee, Florida, at 0814, on August 26, 2001.

About one hour and twenty minutes into the flight, the engine lost power during cruise at 8,000 feet above mean sea level. The pilot completed the emergency procedures, and attempts to restore engine power were unsuccessful. The pilot contacted Valdosta Approach, declared an emergency, and received radar vectors to the nearest airport. While gliding toward the airport, the pilot realized the airplane could not maintain sufficient altitude to cover the distance, and he maneuvered toward a field for an emergency landing. During the descent, the airplane struck power lines and a tree, and then collided with the ground. Emergency response personnel extinguished a post-impact engine fire.

Examination of the airplane revealed approximately 20 gallons of fuel remained in the fuel system. Examination of the engine accessory case revealed the idler gear was fractured, and the two attachment holes in the crankcase for the idler gear shaft assembly were elongated. Three fractured teeth from the idler gear, two separated bolt heads, and a fragment of a bolt threaded end was recovered from inside the accessory case. Metal debris was found in the oil strainer.

The National Transportation Safety Board, Office of Research and Engineering, Materials Laboratory Division, performed metallurgical examination of the idler gear, fractured teeth, and bolt fragments. Examination of the idler gear revealed the surfaces of the teeth displayed damage on both the pressure and non-pressure faces, and some teeth displayed damage on the tip surface. Most teeth displayed surface deformation and pitting consistent with heavy sliding contact. The fracture surface of each fractured gear tooth displayed crack arrest marks and a rough surface consistent with high stress, low-cycle fatigue.

Examination of the two recovered bolt heads revealed the hexagonal corners on each were rounded on the side opposite the threaded end. The shanks below each bolt head were worn uniformly around the circumference, and the diameter of each shank was worn to about one-third the original dimension. Both bolts were fractured in this wear area.

Maintenance records show the engine received a zero-time equivalent overhaul on May 9, 1985, and operated 1371 hours since the overhaul. Textron Lycoming Service Instruction No. 1009AQ states the recommended time between overhaul periods for the engine is 2000 hours. The Lycoming parts catalog for the engine specifies a bolt is required to attach the idler gear shaft assembly at one attachment hole, and a slotted nut and stud are required to attach the idler gear shaft assembly at the other attachment hole.