What happened
While in the cruise phase of flight, the airplane experienced a complete failure of its electrical system. Upon realizing the failure had occurred, the pilot shut down all electrical items and diverted to an alternate airport to perform a precautionary landing.
As the aircraft approached the alternate airport, the pilot reduced airspeed to the normal gear extension speed and used the automatic switch to lower the landing gear. The pilot reported feeling the gear extend; however, because the electrical failure prevented the landing gear lights from illuminating, he could not visually verify that the gear was in the locked position. After performing the emergency gear extension checklist, the pilot noted that his airspeed and power settings were consistent with what he expected when the gear was down.
While the initial touchdown was normal, the nose and left main landing gear collapsed during the landing rollout. This caused the left wing to strike a taxi light. Before exiting the aircraft, the pilot turned off the master switch.
The investigation
During the recovery of the aircraft, investigators raised the plane on jacks and extended the landing gear, noting no discrepancies. Subsequent repair work included a landing gear extension and retraction test, which revealed no system anomalies. An inspection of the aircraft was unable to identify the cause of the initial electrical failure.