Introduction
A certificated commercial pilot was flying a single-engine airplane equipped with a retractable tricycle landing gear. The landing gear was hydraulically actuated by an electrically powered reversible pump. The emergency extension handle allowed manual release of hydraulic pressure to let the gear free-fall.
Flight and Electrical Failure
Approximately 26 miles from the destination airport, the pilot observed signs of an electrical failure. The instrument panel-mounted ammeter indicated zero, prompting the pilot to shut off all electrical equipment.
Landing Gear Malfunction
Upon arrival at the destination airport, the pilot placed the landing gear extension handle in the down position. The gear failed to extend, and the gear down lights did not illuminate.
Emergency Gear Extension Attempt
The pilot followed the flight manual procedures for emergency gear extension. The airplane was slowed to 87 knots, and the pilot held the landing emergency gear lever in the "EMERGENCY DOWN" position while fish-tailing the airplane. To determine if the gear had extended, the pilot checked the airplane's shadow and noted that the gear appeared to be down.
During touchdown, the left main landing gear collapsed, and the left wing struck the runway surface.
Postaccident Examination
A postaccident examination revealed that the voltage regulator had failed, which subsequently led to the loss of electrical power. In the case of a complete electrical failure, the landing gear down lights will not illuminate.