Flight and Initial Operations
The pilot reported that the engine start and airplane power-up were normal for the air medical flight, which carried two medical crewmembers. The engine ice vanes were lowered as required for ground operations and then raised before takeoff. Takeoff and climbout were routine, and the pilot leveled off at the assigned cruise altitude.
Electrical Power Loss
While en route, the air traffic controller informed the pilot of heavy showers near the destination airport, prompting the pilot to lower the ice vanes. Shortly thereafter, the airplane experienced two quick electrical power fluctuations where "everything went away and then came back." Seconds later, the entire electrical system failed. With the loss of navigation capability in instrument meteorological conditions (IMC), the pilot set a general course based on preflight weather briefing information.
Engine Failure and Landing
While attempting to find a hole in the clouds to descend through visually, the left engine lost power. The pilot located a field through the cloud cover and executed a single-engine off-airport landing, which resulted in substantial damage to the right engine mount and firewall.
Postaccident Examination
A postaccident examination of the airplane and systems did not reveal any anomalies consistent with an in-flight electrical system malfunction. The three-position ignition and engine start/starter-only switches were in the ON position, and the engine anti-ice switches were in the ON position. When the airplane battery was initially checked, the voltmeter indicated 10.7 volts (normal voltage is 12 volts); the battery was charged and appeared to function normally thereafter.
The loss of electrical power was likely initiated by the pilot inadvertently selecting the engine start switches instead of the engine anti-ice (ice vane) switches. This caused the starter/generators to change to starter operation, taking the generator function offline. Airplane electrical power was then supplied solely by the battery, which depleted and led to total loss of electrical power.
Examination revealed that neither wing fuel tank contained any visible fuel. The left nacelle fuel tank did not contain any visible fuel, and the right nacelle fuel tank appeared to contain about 1 quart of fuel. The lack of fuel onboard at the time of the accident is consistent with a loss of engine power due to fuel exhaustion, resulting from the extended flight time as the pilot attempted to exit instrument conditions after the loss of electrical power.
The operator reported that 253 gallons (1,720 lbs) of fuel were on board at takeoff, and the accident flight duration was 3.65 hours. At maximum range power, expected fuel consumption was about 406 lbs/hour, yielding an endurance of about 4.2 hours. Thus, the pilot did not have adequate fuel reserves for IMC flight.
Crew Coordination
Both the pilot and medical crewmembers described a lack of communication and coordination during the emergency. This resulted in multiple course adjustments that hindered the pilot's ability to locate visual meteorological conditions before the left engine fuel supply was exhausted.