Oregon

The cockpit voice recorder (CVR) recording indicated that the pilot was unable to start the right engine before takeoff, and elected to attempt takeoff with the right engine inoperative. Witnesses reported that the airplane's nose lifted off about 4,100 feet down the runway and that it then became airborne with its wings rocking, attaining a maximum altitude of 5 to 10 feet above the ground before settling back to the ground, departing the right side of the runway and entering an upright slide for about 1/2 mile. Investigators removed the right engine starter-generator from the engine after the accident and found the starter-generator drive shaft to be fractured. The aircraft has a minimum crew requirement of two, consisting of pilot and copilot; the copilot's seat occupant, a private pilot-rated passenger, did not hold a multiengine rating and thus was not qualified to act as second-in-command of the aircraft.

About three hours and twenty minutes after departing Bellingham, Washington, for Midland, Texas, the pilot contacted Klamath Falls (Oregon) Tower and told the controller of his intention to land. About 10 minutes later, while about 30 miles north of Klamath Falls, the pilot reported he was low on fuel and was not able to find the city. The tower responded with instructions that would take the pilot south to the airport. But because the pilot seemed not to be following the instructions, but was instead continuing to the west, he was switched to Seattle Center. Center provided the pilot with a southeasterly heading direct to Klamath Falls, but less than a minute later radar and radio contact with the aircraft was lost. Other pilots overheard the pilot transmit that he had lost power in one engine, and later state that he had lost power in both. Soon thereafter the aircraft was seen to descend to about 200 to 300 feet above the surface of Lake of the Woods. The aircraft then began to slow and its nose began to rise. As it was slowing, one of the engines surged back to a high power setting, and the aircraft almost immediately rolled quickly to the side and dove nearly straight down into the lake. During the post-accident inspection of the airframe, the throttle for the right engine was found retarded to idle, but 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 for a failed engine (both engines in this case) to be retarded to the 'Cracked 1/2 inch open' position. Toxicological results indicate the presence in the pilot's blood of chlordiazepoxide and three of its active metabolites, norchlordiazepoxide, nordiazepam, and oxazepam. Chlordiazepoxide (Librium) is a tranquilizer often used to treat anxiety and tension. At sufficient levels it can have significant adverse effects on judgement, alertness, and performance. It is known to cause drowsiness, mental dullness, and euphoria. The results also indicate the presence of diphenhydramine in the pilot's blood. Diphenhydramine is a sedating antihistamine, and in sufficient quantities is known to produce drowsiness, impaired coordination, blurred vision, and reduced mental alertness.

Shortly after reaching a cruising altitude of 9,500 feet, the aircraft's course was observed on radar to change from southeasterly to southwesterly. Its average ground speed decreased from 170 knots to 108 knots during this track change. The pilot called ATC with his call sign, and about five seconds later, an unintelligible, one-second-long transmission was heard. At that same time, radar information showed the aircraft at 8,800 feet. Radar and radio contact were lost shortly thereafter. Three days later, wreckage was found where the aircraft had crashed. The crash site was 1,820 feet above sea level and 1/2 mile south-southwest of its last observed radar position; the aircraft's average descent angle from the 8,800-foot-altitude position to the crash site was about 51 degrees. The aircraft was extensively damaged during impact. No damage was noted on tall trees that surrounded the accident site. Also, no preimpact mechanical malfunction or failure of the aircraft or engines was found, and no pre-accident impairment of the pilot was found.

Approximately two minutes after takeoff, witnesses saw the airplane pull up sharply into a steep climb from underneath an 800-foot ceiling. The airplane went into an uncontrolled, nearly vertical dive and impacted into a river. The pilot did not hold multi-engine or instrument ratings. Individuals who knew the pilot, including an instructor who had flown with him, stated that they had doubted the pilot's competence but that the pilot had been confident of his own flying ability.

Witnesses reported seeing the airplane flying in a normal cruise attitude when it rolled inverted and the nose dropped near vertical to the terrain. The airplane descended in a near vertical dive. The nose of the airplane started to come up horizontal to the terrain when it struck a 75-ft tree. During the post crash investigation, no evidence of a mechanical failure or malfunction was found. Both occupants were killed.

During a scheduled cargo flight, the pilot diverted from the normal route and travelled through mountainous terrain. The radar plot indicated that the airplane was in a gradual climbing left turn when the collision occurred. The weather in the area at the time of the accident reported snow showers in the mountainous area. The pilot, sole on board, was killed.

Witnesses heard the airplane circle twice before the approach. A fog bank had just rolled into the area and visibility was reduced to approximately one mile with the bases at 200 to 300 feet. The airplane was observed emerging from the fog in a steep left turn and descending rapidly; right of center line, on a one mile final. The left bank angle increased to near 90° when the nose dipped down and the airplane collided with a parked vehicle 150 feet right of centerline and 50 feet short of the runway. Unicom not manned. No radio in ambulance on ground. Basic weather data shown from north bend, 60 miles north. All three pilots were killed.

While en route, the pilot encountered headwinds and trace rime icing. He made a climb from 17,000 feet to FL190, then to FL210. After cruising at FL210 for about 27 minutes, the aircraft entered a descent (without ATC clearance). Radio and radar contact were lost in the vicinity of were the aircraft crashed. Just before impact, the aircraft was observed to descend out of low clouds in a spin. The pilot had been issued a Canadian instrument rating on 1/11/88, but it was valid for only 12 months. A person, who had given the pilot proficiency flight training in preparation for an instrument qualification check, reported that he had reservations about the pilot's ability to fly in instrument conditions without an autopilot. Avionics personnel at the departure airport reported the pilot had encountered an autopilot malfunction on the previous flight and that they had found an electrical short in the autopilot disconnect switch on the copilot control yoke. However, they were unable to repair it due to lack of a replacement part. Reportedly, the pilot borrowed a soldering iron to repair it himself. All three occupants were killed.

The DHC-6 Twin Otter, C-GKBM, was under contract to the U.S. Forest Service. It was to be repositioned to John Day, OR to pick up passengers. At 11:35 PDT, the pilot checked in with John Day Dispatch and transmitted his expected time of arrival would be 12:15 PDT. About 11:40 the aircraft contacted three trees with the right wing at the 5,000-foot level of Battle Creek Mountain. This impact separated the wing into three sections before the aircraft "exited" over the mountain edge. The final impact site was on this ridgeline with the aircraft coming to final rest in a steep canyon to the east. There was a high mountain further east on the flight path that also needed to be crossed before a descent to John Day, Oregon could be commenced. The pilot's medical records indicated the he had been having medical problems, some of which he did not want brought to the attention of the Medical Doctor (MD) designated by the FAA to do flight physicals. In addition, he did not tell his supervisor that he was having medical problems. It was noted that he had complaints of chronic muscular neck pains, back problems, falling asleep, allergy problems, numbness in the top of his feet, feeling tired and run down, and pain in his legs. The flight track showed a gradual descent of about 400 feet per minute. He was off course to the right for about five minutes before impacting with trees. This flight tract strongly supported a very high probability of sleep-induced unconsciousness.

Shortly after the aircraft touched down on the runway, the right main gear collapsed. Despite the pilot's attempts to correct the situation with left rudder and braking, the aircraft veered to the right of the runway and collided with a building. Shortly after it struck the building, a fire erupted, which totally consumed the aircraft and the building. Due to the severity of the fire, the fracture surfaces of the right landing gear were obliterated.