Accident Overview
On June 25, 2012, at about 0940 Alaska daylight time, a Piper PA-32 airplane, registration N8908N, was involved in a forced landing approximately 5 miles southeast of Gustavus Airport, Gustavus, Alaska. The aircraft was operated by Air Excursions, Gustavus, as a scheduled commuter flight under visual flight rules (VFR) and 14 CFR Part 135. The pilot and three passengers were not injured. Visual meteorological conditions prevailed, and company flight following procedures were in effect. The flight originated from Juneau International Airport at about 0923 and was destined for Gustavus.
Pilot Actions
According to a written statement from the pilot to the National Transportation Safety Board (NTSB), the departure and initial portion of the flight were uneventful. Approximately 11 miles from Gustavus, the engine began to lose power, and the airplane experienced shaking. The pilot performed the emergency procedures checklist for "Engine Power Loss In-Flight," but the power loss and shaking worsened. About 8 miles from Gustavus, the pilot elected to shut down the engine and executed a forced landing on a beach.
Damage Description
During the landing, the nose landing gear collapsed rearward under the airplane, and the engine firewall sustained substantial damage. The aircraft was substantially damaged.
Engine Examination
Initial examination by a Federal Aviation Administration inspector revealed a bulge in the engine crankcase and difficulty rotating the propeller by hand. The airplane was equipped with a Lycoming IO-540 engine. A postaccident examination of internal engine components was conducted by a Materials Research Engineer at the NTSB Materials Laboratory. The examination showed that the crankshaft had fractured forward of the #6 bearing journal through the counterweight web. The fracture surfaces were consistent with fatigue. No other failure modes were identified. Damage to other internal components was consistent with overstress that occurred after the crankshaft failure. The cause of the fatigue crack initiation could not be determined.
Maintenance History
Maintenance record entries indicated that the operator had been troubleshooting engine vibration problems on the accident airplane since at least March 10, 2012.