ORLAND, CA, USA
N37698
ALON A2
DURING A LOCAL AREA PERSONAL FLIGHT, THE PILOT PERFORMED AN AEROBATIC MANEUVER. NO ONE OBSERVED THE ACTUAL MANEUVER; HOWEVER, ONE WITNESS SAW THE AIRPLANE SECONDS PRIOR TO THE CRASH, AND HE INDICATED THE AIRPLANE WAS FALLING 'LIKE A ROCK.' THE OUTBOARD 3-FOOT-LONG PORTION OF THE LEFT WING WAS FOUND IN AN OPEN FIELD ABOUT 200 YARDS FROM THE MAIN WRECKAGE. PRIOR TO THE PILOT'S TAKEOFF, HE HAD INFORMED AN ACQUAINTANCE THAT HE PLANNED TO 'DO SOME ROLLS.' A WEEK EARLIER, THE PILOT TOLD HIS WIFE THAT HE WANTED TO TRY TO ROLL HIS AIRPLANE. THE PILOT HAD NOT RECEIVED AEROBATIC FLIGHT TRAINING, AND THE AIRPLANE WAS NOT CERTIFICATED TO PERFORM ROLLS. EXAMINATION OF THE LEFT AILERON AND LEFT WING STRUCTURE REVEALED PERMANENT DEFORMATION IN AN UPWARD (POSITIVE) DIRECTION. FAA AIRWORTHINESS AND CERTIFICATION OFFICE PERSONNEL REPORTED NO SIGNS OF A DEVELOPING OR PREEXISTING CONDITION WHICH INDUCED FAILURE OF THE SEPARATED LEFT WING TIP.
HISTORY OF FLIGHT On September 17, 1994, around 1030 Pacific daylight time, an Alon A2, N37698, owned and operated by the pilot, experienced an in-flight breakup near Orland, California. The airplane was destroyed and the private pilot was fatally injured. Visual meteorological conditions prevailed during the local area personal flight. A commercial pilot reported that he had known the accident pilot for over 7 years, and he had spoken with him on the morning of the fatal flight. In pertinent part, the commercial pilot recalled that the accident pilot told him he planned to "do some rolls." Personnel at the Haigh (uncontrolled) Airport in Orland observed the accident airplane depart around 1000, and it was not seen thereafter. No witnesses reported having observed the in-flight breakup to the National Transportation Safety Board. One witness reported hearing the airplane's engine stop and then observing the airplane descending "like a rock." Around 1050, the wreckage was found in an open field about 7 miles east of Orland. The crash site was approximately 5 miles east of the Haigh Airport. AIRCRAFT INFORMATION A review of records indicated that in 1967 the pilot purchased the airplane in a condition which he had described as being "a wrecked (Alon-2) aircraft," bearing registration N5673F. Thereafter, the pilot rebuilt the airplane, and the Federal Aviation Administration (FAA) issued it the current registration number. The airplane was modified during the reconstruction. The records indicated that the modifications were, in part, made pursuant to the issuance of Supplemental Type Certificate (STC) SA 4331WE, and included the installation of a Continental C85-12F engine and a McCaulley 1B90/CA 7150 propeller. The airplane was certificated in the normal category. No aerobatic maneuvers, such as rolls, were authorized. WRECKAGE AND IMPACT INFORMATION From an examination of the accident site, airplane wreckage, and from the witness statement, the airplane was found to have crashed into an open field with no evidence of forward airspeed. With the exception of the outboard 3-foot-long span of left wing tip, all of the main wreckage was found in, or adjacent to, the initial impact crater which matched the size and shape of the main wreckage. The left wing tip was located an estimated 200 yards south of the crater. At least six skin and metal fragments were found in the field between the wing tip and the main wreckage. There was no evidence of fire. The propeller and spinner were found about 1 foot below ground level. Upon recovery, the propeller was observed bent into an "S" shape. Its leading edge was found gouged, and scratches were apparent over its cambered surface. The engine was found in about an 80-degrees nose-down pitch attitude. Fuel was found in fuel lines, in the carburetor, and in the gascolator. The continuity of the flight control system was established between the cockpit and all of the flight control surfaces. The left aileron, and the outboard portion of the left wing adjacent to the area where the wing tip had separated, were found deformed in an upward (positive) direction. Relative to the fuselage, the empennage was found torsionally bent in a clockwise direction. MEDICAL AND PATHOLOGICAL INFORMATION On September 19, 1994, an autopsy was performed by Robert M. Anthony, M.D., 543 W. Oak Lane, Willows, California 95988, for the Glenn County Coroner/Sheriff's Office. The results of toxicology tests performed by the Armed Forces Institute of Pathology were negative for ethyl alcohol and all screened drugs. TESTS AND RESEARCH In addition to the Safety Board's examination of the wreckage, FAA personnel from Aircraft Certification Offices in Los Angeles, California, and Denver, Colorado, and an airworthiness inspector from the Flight Standards District Office in Sacramento, California, participated in the examinations. In pertinent part, the FAA reported that all fracture surfaces were examined on the left wing tip which separated in flight. The fractures "appeared to be failures due to in-flight overload. No signs of a developing or preexisting condition which may have induced failure were noted." ADDITIONAL INFORMATION On November 29, 1994, the pilot's wife reported to the Safety Board that a week before the crash her husband informed her that he wanted to try to roll his airplane. She also stated that he had no aerobatic flying experience. Upon verbal request from the pilot's wife, on December 2, 1994, all recovered wreckage was verbally released to Tom Dunston, A & P Mechanic, Haigh Airport, Orland, California. No parts were retained.
the pilot's intentional performance of an aerobatic maneuver which overloaded the outboard portion of the left wing and caused it to fail. Factors which contributed to the accident were the pilot's overconfidence in his ability to perform the maneuver and his lack of experience or training in aerobatics.
Source: NTSB Aviation Accident Database
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