IAD02LA053

The airplane was en route when the engine lost partial power. The pilot was unable to maintain airspeed or altitude, and elected to perform a forced landing to a field. During the landing, the airplane struck a fence post with the left wing. Examination of the engine crankcase halves revealed severe fretting at the number 2 main bearing bosses. The number 2 main bearing was broken into pieces and observed in the oil sump. Examination of the crankshaft revealed a fatigue fracture through the crank cheek between the number 2 main journal and the number 2 rod journal. The fracture surface and the journal surface were heat-tinted, and revealed evidence of rotational scoring. According to the engine logbook, the crankcase through bolts were torqued about 772 hours prior to the accident.

On May 29, 2002, at 1510 eastern daylight time, a Beech V35A, N45RG, operated by SkyWorld Aviation, was substantially damaged during a forced landing following a loss of power in Martinsburg, West Virginia. The certificated commercial pilot sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the positioning flight conducted under 14 CFR Part 91.

According to the pilot, he had flown from Warrenton-Fauquier Airport (W66), Warrenton, Virginia, to Hagerstown Airport (HGR), Hagerstown, Maryland, earlier in the day so that a pitot-static system inspection could be completed on the airplane. After the inspection was completed, the pilot attempted to start the engine, but was unsuccessful. When a ground power unit was used, the engine started, and the pilot performed run-up checks. He then departed Hagerstown to return to Warrenton, where the airplane was based. The pilot leveled the airplane at 4,000 feet, and completed the cruise checklist. He noted that the rpm indication was about 2,400, and the manifold pressure indicated about 22 inches.

As the airplane approached the Casanova VOR, approximately 7 miles from Warrenton, the engine lost partial power. The airplane "yawed and rolled" about 5 degrees in each direction, and the engine noise increased slightly. The engine continued to run, but was "not running right," as the airplane continued to lose altitude and airspeed.

When the airplane was at 3,000 feet and 6 miles from the Eastern West Virginia Airport (MRB), Martinsburg, West Virginia, the pilot declared an emergency and looked for a field to land in. He trimmed the airplane for best glide speed (105 knots), and secured the engine using the checklist. The pilot extended the landing gear, retrimmed the airplane and made a right turn for the base leg of the field. During the landing rollout, the airplane struck a fence post with the left wing, spun around, and the nose wheel dug into the ground.

Preliminary examination of the engine revealed that continuity could not be obtained by manual rotation of the propeller. The spark plugs were removed, and visual observation revealed their electrodes were light gray in color. Fuel was observed in the fuel lines, fuel manifold, and the fuel pump. The #3, #4, #5, #6 cylinders were removed, and no abnormalities were noted to their pistons or connecting rods. The #1 cylinder was removed; however, the piston could not be moved from the engine case housing. The #2 cylinder could not be removed. The oil pan was removed from the engine case, and metal particles were observed in the pan. The oil filter was removed from the engine, and examination of the filter revealed metal shavings and particles.

The engine was further examined at the engine manufacturer's teardown facility, under the supervision of a Safety Board investigator. Examination of the engine crankcase revealed severe fretting at the number 2 main bearing bosses. The number 2 bearing saddle was heavily damaged and extruding aluminum at the edges of the saddle. The number 3 main bearing bosses were also fretted and the bearing was elongating the lock slots.

Examination of the crankshaft revealed it was fractured at the number 2 crankshaft cheek, aft of the number 2 main bearing. The number 2 main bearing was broken into pieces and observed in the oil sump.

The broken section of crankshaft was sent to the Safety Board Materials Laboratory, and examination of the section revealed a fatigue fracture through the crank cheek between the number 2 main journal and number 2 rod journal. According to the Materials Laboratory Factual Report, "The fatigue fracture emanated from multiple origins on the surface of the aft fillet radius of the number 2 main journal. The fracture surface and the journal surface were heat-tinted and showed evidence of rotational scoring. The surface of the journal contained parallel 'ladder cracks' associated with the forces and temperature rise caused by friction, as well as some localized bands of surface damage suggesting adhesive wear."

Examination of the engine logbooks revealed that the number 2 cylinder was replaced on May 20, 1998. Another entry was noted on September 3, 1999, which stated the "cylinder base bolts were torqued," about 772 hours prior to the accident. The last 100-hour inspection was performed on June 25, 2001.

The pilot possessed a commercial pilot certificate with ratings for airplane single and multiengine land, instrument, and helicopter. He reported a total of 877 hours of total flight experience, 28 of which were in make and model.

Weather reported at Martinsburg Airport, at 1453, included winds from 120 degrees at 9 knots, 9 miles visibility, few clouds at 2,800 feet, temperature 25 degrees, dew point 18 degrees, and barometric pressure of 30.07 inches Mercury.