BIGFORK, MT, USA
N618HP
Hoye KOLB TWINSTAR MK III
Witnesses reported observing the aircraft perform various low level flight maneuvers in the area. A witness reported that the aircraft was performing steep turns, and steep climbs and descents prior to the final maneuver. The witness reported that the aircraft began a steep climb from about 300-400 feet above ground level for a few seconds, then nosed down and collided with the terrain in a near vertical attitude. Post-accident inspection of the wreckage did not reveal evidence of a mechanical failure or malfunction.
HISTORY OF FLIGHT On June 20, 2000, about 2030 mountain daylight time, an amateur built Kolb Twinstar Mark III, N618HP, registered to and operated by the pilot as a 14 CFR Part 91 personal flight, collided with the terrain during an uncontrolled descent near Bigfork, Montana. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft was substantially damaged and the private pilot and student pilot passenger were fatally injured. The flight departed from Whitefish, Montana, about 30 minutes prior to the accident. Witnesses in the area reported observing the aircraft perform various flight maneuvers at low levels prior to the aircraft pitching down and colliding with the terrain in a near vertical attitude. One witness, who prepared a written statement, (See witness statement attachment) reported that she was about one and a half miles away, and in her house when she first observed the aircraft. The witness reported that the aircraft was in a steep turn, about 500 feet above ground level, and that both wings were visible to her. The aircraft then went to wings level and began a steep climb. The aircraft then reversed course and decreased altitude as if to land at the Ferndale Airport. The witness then saw the aircraft again about 30 seconds later in a steep climb, starting at about 300-400 feet, for about three seconds. The witness stated, "The angle of this flight is neither over or under exaggerated." (Refer to witness statement diagram). The witness further stated, "I say this especially because that flight angle is hard to believe. He was flying at a good clip going up." The aircraft then turned and came straight down. Another witness, who did not prepare a written statement, but reported to the Flathead County Sheriff's Office, that he was outside when he first saw the aircraft flying over the Ferndale area. The witness reported that the aircraft was in level flight and circling towards the south. The witness then saw the aircraft "nose over and pinwheel slightly and then recover and climb." The aircraft then "tilted on its right wing and dropped out of sight." The witness reported that the engine was running at full power during this maneuver before he heard a loud snap and the engine went silent. WRECKAGE AND IMPACT INFORMATION A Federal Aviation Administration Inspector from the Helena, Montana, Flight Standards District Office responded to the accident site and reported that the aircraft wreckage was located in a grove of tall trees. Several tree limbs directly above the wreckage were broken. Impact signatures were noted along the leading edge of the wings. Control continuity was established from the cockpit to the flight control surfaces. All flight control surfaces were located at their respective positions. The inspector reported that the aircraft was equipped with a ballistic parachute, and noted that the safety pin had been pulled and the chute was armed, however, it had not been deployed. PERSONNEL INFORMATION The co-owner to the aircraft reported that the private pilot had accumulated a total flight time of 81 hours in all aircraft. Approximately 11 hours had been accumulated in the accident aircraft. AIRCRAFT INFORMATION Aircraft records indicate that the aircraft's construction began in July 1998. The aircraft was signed off by a Federal Aviation Administration Inspector and an airworthiness certificate was issued on April 4, 2000. Following the certificate issuance, the aircraft accomplished the first test flight on April 16, 2000. The following seven test flights accomplished over the next two months tested the aircraft's performance during slow flight, stalls, steep turns, climbs, and descents. The entry dated June 15, 2000, at an aircraft total time of 40.5 hours, indicated that the aircraft was "dove" to 110 mph, and that all controls were normal. The last entry dated June 17, 2000, at an aircraft total flight time of 44.5 hours states "I certify the flight test hours have been completed and the aircraft is controllable throughout all maneuvers to be executed. Has no hazardous operating characteristics or design features and is safe for operation. The following operating data has been demonstrated. Vso [stalling speed (landing)] 45 mph, Vx [best angle-of-climb speed] 55 mph , Vy [best rate-of-climb speed] 60 mph and a/c [aircraft] weight of 900 lbs & CG [center-of-gravity] of 21.3." The entry was signed by the co-owner of the aircraft. MEDICAL AND PATHOLOGICAL INFORMATION A post-mortem was performed on both occupants by Sgt. Brock Wilson, Flathead County Sheriff/Coroner, Missoula, Montana. Toxicological samples from the pilot were sent to the Federal Aviation Administration Civil Aeromedical Institute, Oklahoma City, Oklahoma, for analysis. The results of the analysis were negative. ADDITIONAL INFORMATION The wreckage was verbally released to the co-owner at the completion of the on-site investigation on June 21, 2000.
The pilot's failure to maintain aircraft control. Inadequate altitude for recovery was a factor.
Source: NTSB Aviation Accident Database
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