CRESENT LAKE, OR, USA
OKDUU
Cora ALLEGRO
The pilot of the unregistered homebuilt aircraft was departing in strong, gusty winds that were reported to be constantly changing direction. After lifting off about halfway down the 3,800 feet runway, the aircraft appeared to remain less than 20 feet above the ground as it continued to accelerate toward the departure end. As it neared the trees off the departure end of the runway, it appeared that the aircraft started to climb. But, its right wing clipped a tree as the pilot attempted to maneuver into an open corridor formed by a nearby railroad track. At the time of the accident, the density altitude was about 5,300 feet, and a pilot that had just departed said that the air was very bumpy just above treetop level. No evidence of anomalies or malfunction were found in the airframe or engine.
On September 18, 1998, approximately 1045 Pacific daylight time, a Cora Allegro, registered by the Czech Home-built Aviation Association as OKDUU, collided with trees while taking off from Crescent Lake State Airport, Crescent Lake, Oregon. The private pilot, who was the sole occupant, received fatal injuries, and the aircraft, which was owned and operated by the pilot, was destroyed by the impact and subsequent fire. The 14 CFR Part 91 personal pleasure flight, which was departing for a dry lake in the Alvord Desert, about 20 miles north of Fields, Oregon, was being operated in visual meteorological conditions. No flight plan had been filed, and there was no report of an ELT activation. According to witnesses on the ground, the aircraft lifted off about half-way down the 3,800 foot runway, and remained very low (less than 20 feet AGL) as it continued to accelerate straight ahead over the runway. As it neared the trees off the northwest end of the runway, it appeared to start to climb, and the witnesses thought it would clear the trees. When it reached the trees, the aircraft was seen turning to the left, and then it disappeared from sight. A pilot who had departed shortly before the accident aircraft, and was flying overhead, reported that it appeared the pilot attempted to maneuver around the trees into an open corridor formed by nearby railroad tracks, but that the aircraft's right wing impacted one of the trees as the pilot attempted to turn. Immediately after impacting the tree, the aircraft cartwheeled into the terrain, came to rest inverted, and burst into flames. The pilot who took off just prior to the accident said that there was a gusty wind blowing from the general direction of northwest, and that the air was very bumpy just above the tree tops. Witnesses on the ground said that the wind was gusting to at least 25 miles per hour, and that its direction was constantly changing. One witness reported that the wind sock was standing straight out, and that it kept moving back and forth from southeast to west. The temperature was estimated to be about 50 degrees Fahrenheit, and the density altitude was calculated to be about 5,300 feet. The two FAA Airworthiness Inspectors who responded to the accident scene were unable to find any evidence of airframe or system failure, and there was no indication of any engine malfunction or anomaly. Witnesses who heard the aircraft departing reported that the engine sounded as if it were running smoothly. The aircraft, which carried the registration number OKDUU on its fuselage, was not registered in the United States. According to Czech officials, the aircraft was not registered by the Czech Aviation Authority in any category. Instead, it was registered by the Czech Home-built Aviation Association as "Sport Flying Equipment" (vehicle), and was limited to private flying within Czech airspace only. The autopsy indicated that the pilot's cause of death was accidental, and the toxicological examination performed by the FAA's Toxicology and Accident Research Laboratory, indicated no cyanide or drugs were found in his blood. The examination did reveal 25% carbon monoxide in the pilots blood, but according to the laboratory, this is most likely attributable to the pilot's inhaling the byproducts of the post-impact fire. A review of the Oregon Departments of Transportation's Oregon Airport Guide revealed that this airport is designated as a "Warning Airport." The guide states that "...it may also require special techniques and procedures to use."
The pilot's failure to maintain clearance from trees located off the departure end of the runway. Factors include strong, variable, gusty winds, terrain-induced turbulence, a high density altitude, and trees off the departure end of the runway.
Source: NTSB Aviation Accident Database
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