Incident Overview
Approximately three hours and twenty minutes after departing Bellingham, Washington, en route to Midland, Texas, the pilot contacted Klamath Falls Tower and announced his intention to land. About 10 minutes later, while approximately 30 miles north of Klamath Falls, the pilot reported being low on fuel and unable to locate the city. The tower provided instructions to guide the pilot south to the airport. However, the pilot appeared to deviate westward, prompting a switch to Seattle Center, which gave a southeasterly heading direct to Klamath Falls. Less than a minute later, radar and radio contact with the aircraft was lost.
Sequence of Events
Other pilots overheard the pilot transmit that he had lost power in one engine, and subsequently stated that both engines had failed. The aircraft was then observed descending to an altitude of about 200 to 300 feet above the surface of Lake of the Woods. The aircraft began to slow, and its nose rose. As it decelerated, one of the engines surged back to a high power setting. The aircraft almost immediately rolled rapidly to the side and dove nearly straight down into the lake.
Post-Accident Findings
During the post-accident inspection, the throttle for the right engine was found retarded to idle, while the throttle for the left engine was found in the full-forward (maximum power) position. A review of the Aerostar owner's manual revealed that the Engine Failure/Restart checklist called for the throttle of a failed engine (both engines in this case) to be retarded to the 'Cracked 1/2 inch open' position.
Toxicological tests detected the presence of chlordiazepoxide (Librium) and three of its active metabolites (norchlordiazepoxide, nordiazepam, and oxazepam) in the pilot's blood. Chlordiazepoxide is a tranquilizer used to treat anxiety and tension; at sufficient levels it can impair judgment, alertness, and performance, and may cause drowsiness, mental dullness, and euphoria. Diphenhydramine, a sedating antihistamine, was also found. In sufficient quantities, diphenhydramine can cause drowsiness, impaired coordination, blurred vision, and reduced mental alertness.