What happened
Approximately three hours and twenty minutes after departing from Bellingham, Washington, en route to Midland, Texas, the pilot of the Aerostar contacted Klamette Falls Tower to announce intentions to land. Roughly ten minutes later, while positioned about 30 miles north of the airport, the pilot notified controllers that the aircraft was low on fuel and that the pilot was unable to locate the city. Although the tower provided directions to head south toward the airport, the pilot continued traveling west, prompting a transfer of communication to Seattle Center. After receiving a southeasterly heading, radio and radar contact with the aircraft was lost within a minute.
Other pilots in the area heard the pilot report an engine failure, followed by a report that both engines had lost power. The aircraft was subsequently observed descending to an altitude of approximately 200 to 300 feet above Lake of the Woods. During this descent, the aircraft slowed and the nose pitched up. As the speed decreased, one engine surged to a high power setting, causing the aircraft to roll sharply and dive vertically into the lake. The accident resulted in fatalities.
Findings
Post-accident inspections of the airframe revealed that the right engine throttle was at idle, while the left engine throttle was at maximum power. According to the aircraft owner's manual, the engine failure checklist required throttles for failed engines to be set to a specific partial-open position, which was not followed. The presence of sedative substances in the pilot's blood was also identified. Toxicological analysis showed the pilot had chlordiazepoxide and its metabolites, as well as diphenhydramine, in his system. These substances are known to cause drowsiness, impaired coordination, and reduced mental alertness.