Aviation Accident Summaries

Aviation Accident Summary SEA96FA034

KAPOWSIN, WA, USA

Aircraft #1

N4008Z

Piper PA-18-150

Analysis

During a personal pleasure flight to sight see and spot elk, the airplane collided with rolling mountainous terrain in a nearly vertical attitude. Other pilots flying in the area reported windy and turbulent conditions around the mountains. During the postcrash investigation of the airframe and engine, no evidence was found to indicate a mechanical failure or malfunction.

Factual Information

HISTORY OF FLIGHT On December 23, 1995, approximately 1600 Pacific standard time, a Piper PA-18-150, N4008Z, collided with mountainous terrain near Kapowsin, Washington. Visual meteorological conditions prevailed at the time and no flight plan was filed for the local pleasure flight. The airplane was substantially damaged and the airline transport pilot and his passenger were fatally injured. The flight had departed from a private airstrip near South Prairie, Washington, on December 23, 1995, approximately 1530. Family members reported that the purpose of the flight was to sight-see in the area and to try to spot elk. The flight was due back at South Prairie at 1630. When the flight did not return, family members notified the search agency. Local residents who live near the airport and flew on the day of the accident reported moderate turbulent conditions below 2,000 feet around the foothills. The turbulent conditions diminished in the valley and flat lands. The weather to the south and to the east were clear, while the weather to the west was foggy. PERSONNEL INFORMATION The pilot held an airline transport pilot certificate and was rated for single and multi-engine land, and single-engine sea operations. The pilot was employed as a captain with a commercial airline operator and flew the Boeing 757. The pilot's son reported that the pilot logged his flight time in two separate flight logbooks for commercial airline activity and general aviation activity. Total flight time added from both books was reported to be 18,176 hours. The total flight time for the make and model aircraft in which the accident occurred, was 146 hours. Aircraft records indicate that the pilot purchased the airplane on June 28, 1995. The pilot's general aviation flight logbook indicates that he had accumulated a total flight time of 46 hours at the time of the accident. It was reported that the pilot had owned another PA-18 several years ago. WRECKAGE AND IMPACT INFORMATION The wreckage was located at the 2,200 foot level of an approximate 2,300 foot mountain. The ground was covered with brush and sparsely populated new growth trees measuring in height to ten feet. There was no evidence found, outside of the immediate area, to indicate a wreckage distribution path. The wreckage was positioned nose down and on a magnetic heading of 130 degrees. The fuselage was positioned upward and the empennage was bent nearly ninety degrees to the right. The entire wing area and top of the cabin was bent forward with the leading edge of both wings contacting the ground. The right wing was positioned on the downhill side, with the left wing on the uphill side. The terrain angle was approximately 10 degrees. The outboard seven feet of the right wing was laying on the ground, and was bent upward. Leading edge rearward crushing was noted. Both the flap and the aileron remained attached to their respective hinges. The right flap was retracted. The left wing outboard six feet of the leading edge was crushed rearward. A six foot long narrow ground indent was noted approximately five feet in front of the damaged area of the wing. Broken plexiglass from the landing light case was found in this indent. Both the aileron and the flap remained attached to their respective hinges. The left flap was positioned down and over-extended. The control cables were jammed tight and movement was not possible due to the forward bending of the wing section. The flap lever was found in the 25 degree extended position. The horizontal and vertical stabilizers remained intact with the rudder and elevator attached. The right side horizontal stabilizer was positioned on the ground and was bent upward. Control cable continuity was established from the empennage to the rear cabin area. The control stick remained attached, however, movement was not possible due to impact damage. The engine remained attached to the fuselage and the nose was positioned down and partially buried in the ground. The propeller remained attached to the crankshaft, however, the propeller flange was cracked. One propeller blade was visible at the approximate 11 o'clock position. The propeller blade displayed an "S" bending and three gouges at the outboard six inches of the blade tip were noted. The other blade was buried in the ground under the airplane. After the soil was removed, it was noted that the blade was nearly straight and the outboard four inches of the tip was broken off. Cockpit documentation revealed that the throttle was open and the mixture was rich. Carburetor heat was cold and the primer was in and locked. The left magneto switch was off, while the right one was on. The right fuel gauge was indicating empty, and the left fuel gauge was indicting between one-half and three-quarters. During the engine inspection it was found that the crankshaft rotated easily with accessory gear and valve train continuity established. Suction and exhaust were noted to each of the cylinders. The left magneto was destroyed by impact, however, the right magneto was found to rotate and produced a spark from all four towers via hand rotation. The fuel filter was clear of contaminants. The carburetor was removed and opened for inspection. Clear blue fuel was found in the carburetor bowl. The accelerator pump produced a steady stream of fuel when operated. The floats were intact and all ports were clear of obstructions. Oil remained present in the crankcase. MEDICAL AND PATHOLOGICAL INFORMATION The Pierce County Medical Examiner, Tacoma, Washington, determined that the pilot's cause of death was due to multiple injuries. Toxicological samples were sent to the Department of Laboratory Medicine University of Washington, Seattle, Washington, for examination. The results of those tests were reported as negative. ADDITIONAL INFORMATION The wreckage was released to the pilot's family on January 5, 1996. The wreckage was stored at the owner's residence.

Probable Cause and Findings

the pilot's failure to maintain aircraft control and terrain clearance. Turbulence was a factor.

 

Source: NTSB Aviation Accident Database

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