Alternator Failures in Heavy Rain
Approximately 40 miles from the destination, while operating in heavy rain, both alternators failed. The electrical load was subsequently reduced, and a radar-monitored instrument landing system (ILS) approach was conducted. After descending through clouds into visual meteorological conditions (VMC), the pilot attempted to lower the landing gear electrically.
Electrical Power Loss and Landing Gear Extension
At the moment of the gear-down selection, all electrical power was lost. The manual emergency gear extension system was then used; resistance was felt during the cranking process.
Post-Landing Gear Retraction
During the landing rollout, the landing gear retracted. The landing gear motor circuit breaker had not been pulled prior to manually cranking the gear down, as specified in the pilot's operating handbook.
Manufacturer Service Information
Cessna Aircraft Corporation had published two service information letters applicable to aircraft equipped with the same engine and alternator installation as the accident aircraft. These letters were prompted by moisture-induced interruption of alternator output. Additionally, the engine, alternator, and cowling installation of the Beechcraft BE-58P is similar to that of the Cessna aircraft affected by those letters.