Aviation Accident Summaries

Aviation Accident Summary SEA98FA164

WINLOCK, WA, USA

Aircraft #1

N766CA

North American SNJ-5C

Analysis

Witnesses at a residence on the airstrip observed the airplane make a low pass to the east along the east-west runway of the airstrip, followed by an 8-point roll, a 90-270 degree course reversal, and another low pass to the west with a pull-up into what was described as either a loop or cuban-eight maneuver. Just after attaining the top of this last maneuver, the airplane was rolled out with a heading change toward the south, where it was observed to be near level attitude before the left wing dropped and it disappeared from view due to obscuration by trees. Impact was heard shortly after the airplane disappeared from view. The airplane was located in a wooded area and was consumed by fire. One witness familiar with both the pilot and the airplane had noted a slight hesitation at the top of the loop or cuban-eight maneuver. He observed that the winds aloft were quite strong from the north, which may have caused the airplane to drift south of the east-west runway, so that terrain clearance (due to high trees bordering the south side of the runway) would have been reduced when the pilot was at the top of the maneuver. He noted that he heard no indications of a loss of engine power, although some other witnesses at the same location on the airstrip believed there had been a momentary power interruption before the crash. No evidence of preimpact mechanical deficiency or of pre-impact fire was observed during the on-scene investigation.

Factual Information

HISTORY OF FLIGHT On August 13, 1998, approximately 1830 Pacific daylight time, a North American SNJ-5C airplane, N766CA, was destroyed when it collided with trees and terrain while maneuvering in the vicinity of Pilot's Pasture airstrip, near Winlock, Washington. The commercial pilot and his passenger were fatally injured. Visual meteorological conditions prevailed at the time of the accident. The flight had originated at Vancouver, Washington, where the airplane had been refueled, and the destination was the Pilot's Pasture airstrip. There was no report of an ELT actuating. There was a post-crash fire. Witnesses, at a residence beside Pilot's Pasture airstrip whom the pilot was going to visit, observed the airplane make a low pass to the east along the east-west runway of the airstrip, followed by an 8-point roll, a 90-270 degree course reversal, and another low pass to the west with a pull-up into either a loop or cuban-eight maneuver. Just after attaining the top of this last maneuver, the airplane was rolled out with a heading change toward the south and a loss of altitude, where it was observed to be near level attitude before the left wing dropped and it disappeared from view due to obscuration by trees. Impact was heard shortly after the airplane disappeared from view. One witness familiar with both the pilot and the airplane had noted a slight hesitation at the top of the loop or cuban-eight maneuver. He observed that the winds aloft were quite strong from the north, which may have caused the airplane to drift south of the east-west runway, so that terrain clearance (due to high trees bordering the south side of the runway) would have been reduced when the pilot was at the top of the maneuver. He noted that he heard no indications of a loss of engine power, although some other witnesses at the same location on the airstrip believed there had been a momentary power interruption before the crash. Other witnesses not on the airstrip saw the maneuvering and heard the crash impact. Their statements are attached. AIRCRAFT INFORMATION The certification basis of the former military trainer was CAR 4a. PERSONNEL INFORMATION The pilot's flight review requirements (BFR), were fulfilled by his acquisition of a multi-engine rating March 17, 1997. WRECKAGE AND IMPACT INFORMATION The wreckage was found in a wooded area with mature trees, about .4 miles west of North Military Road (on the 200 block of Sargent Road), and about .12 miles north of Sargent Road. The fuselage and empennage were substantially consumed by fire. The flaps were found to be in the retracted position, and the landing gear was in the up position. The wreckage distribution path was approximately 170 degrees magnetic from the first tree with observed impact damage; the length of the distribution path was approximated as 100 yards (vegetation constraints precluded precise measurement). Several trees between that first tree (which exhibited topping) and an impact crater sustained topping and limb breakage and significant impacts on their trunks. Those impacts were consistent with an approach angle of about 40 degrees down from the first tree to the impact crater, which was about 2/3 of the way through the wreckage distribution path. The left flap, some right wing skin and the right wing-tip, and other pieces of sheet metal were located throughout the wreckage distribution path between the first tree and the impact crater. The engine and propeller were found about ten feet beyond the impact crater. The carburetor was separated from the engine, and it exhibited both impact and fire damage. The engine accessory case was separated from the rear of the engine. The left side of the engine (from the aft) exhibited crushing and deformation of the push-rod tubes and push-rods, and displacement (aft) of at least one cylinder. This damage was concave, in a vertical axis, and showed evidence or residual wood fibers and bark. One blade of the propeller was comparatively straight, with leading edge gouging, scratching, and abraded paint. The other blade was embedded in the ground, with its exposed section bent aft in a smooth radius, initiating about 12-18 inches from the hub. Cylinder heads exhibited impact damage. Fire in the area had consumed localized vegetation; however, the major portion of the engine did not exhibit fire damage. The wings and wing carry-through structure were further into the wreckage distribution path. The right wing, with its tip separated, but with the aileron remaining attached, was found with the left wing under it. The tail cone and steel-tubing fuselage center-section were located furthest into the wreckage distribution path. The vertical fin was noted to be folded over 90 degrees to the right. The fuselage center section, and the wing carry-through section, were heavily consumed by post-crash fire. The instrument panels were destroyed by fire. The only cockpit documentation noted was the position of the rear seat fuel selector, which was found with the pointer near the left position. The fuel selector pointer drives a rod to a remote fuel selector on this installation. No evidence of preimpact mechanical deficiency or of pre-impact fire was observed during the on-scene investigation. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed upon the pilot August 15, 1998, by Daniel Selove, MD, for the Lewis County Coroner's office. Toxicological testing was performed by FAA-CAMI, with negative results for carbon monoxide, cyanide, ethanol, and drugs. FIRE The wreckage was substantially consumed by post-crash fire. ADDITIONAL INFORMATION The wreckage was transported to Aircraft Specialties, in Bend, Oregon, for storage. It was released to Tracy Barrus, representative of the owner, on October 19, 1998.

Probable Cause and Findings

The pilot's failure to maintain adequate altitude during attempted low-level aerobatics.

 

Source: NTSB Aviation Accident Database

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