Aviation Accident Summaries

Aviation Accident Summary ANC00FA093

THORNE BAY, AK, USA

Aircraft #1

N2997A

Cessna 180

Analysis

The commercial certificated pilot departed from a floating lodge in a float equipped airplane. After lift off, the airplane made a climbing right turn over the lodge and was observed to be in a slight climb attitude. The airplane then appeared to skid to the left. The left wing dropped, and the airplane appeared to stall. It then descended to the ground, making about 1/2 turn to the left. The engine sounds were heard all the way to the ground. The airplane collided with tall trees and then the ground in a nose down attitude, coming to rest in a small clearing of trees. The airplane received extensive impact damage with buckling and twisting of the airframe. The engine and propeller were buried in the ground. No evidence of any preimpact mechanical anomalies were discovered during the on-site investigation. The airplane was not recovered from the accident scene.

Factual Information

HISTORY OF FLIGHT On July 20, 2000, about 1930 Alaska daylight time, a float equipped Cessna 180 airplane, N2997A, was destroyed when it collided with terrain about 3.25 miles east of Thorne Bay, Alaska. The airplane was being operated as a visual flight rules (VFR) local area personal flight, when the accident occurred. The airplane was operated by the pilot. The commercial certificated pilot, the sole occupant, received fatal injuries. Visual meteorological conditions prevailed. The flight originated from a small cove in Tolstoi Bay, located on the Prince of Wales Island. Witnesses reported the pilot was departing a floating lodge in the cove, and was headed to Thorne Bay. The airplane departed toward the northwest, and then made a climbing right turn over the top of the lodge. The airplane appeared to be in a slight climb over wooded terrain when it appeared to make a skidding turn to the left. The airplane then appeared to stall. The left wing dropped, and the airplane descended to the ground in a nose low attitude, making about 1/2 turn to the left. The witnesses described the weather as clear, with calm wind conditions. They also indicated the airplane's engine was not making any unusual sounds, and appeared to be running until colliding with the ground. The accident occurred during the hours of daylight at latitude 55 degrees, 39.92 minutes north, and longitude 132 degrees, 27.30 minutes west. PERSONNEL INFORMATION The pilot held a commercial pilot certificate with airplane single-engine land, single-engine sea, and instrument airplane ratings. The most recent third-class medical certificate was issued to the pilot on December 22, 1998. A review of the pilot's medical certificate file revealed an initial denial of a third class medical certificate on May 15, 1989, due to a limitation of strength and function of his left hand and forearm. The pilot was issued a statement of demonstrated ability, following a medical flight test on December 13, 1989. A Federal Aviation Administration (FAA) inspector who administered the flight test stated, in part: "Mr. Wyatt was able to function without any difficulty. The aircraft had the old pull-to-start handle, which Mr. Wyatt was able to operate with his left arm without difficulty." The aeronautical experience listed on page 3 of this report was obtained from a review of the airmen FAA records on file in the Airman and Medical Records Center located in Oklahoma City, and the pilot's log book. On the pilot's application for medical certificate, dated December 22, 1998, the pilot indicated that his total aeronautical experience consisted of 1,074 hours, of which none were accrued in the previous 6 months. The pilot's logbook reflected a successful commercial pilot flight test for a single-engine sea rating on March 13, 2000. No further logbook entries were noted after that time. The pilot's logbook documented a total aeronautical experience of 1,425.4 hours, of which 322.9 hours were accrued in single-engine seaplanes. During an inquiry about the maintenance history of the accident airplane, maintenance personnel volunteered their comments about the pilot's flying behavior. The comments included a description of the pilot's flying as "cowboy style." The pilot's takeoff profile was described as "yanking the airplane off the water, followed by a steep turn." Another maintenance person commented that the pilot rarely performed a preflight of the airplane, and had previously flown the airplane with a spark plug wire disconnected, a leaking carburetor, and continued to fly the airplane with a hole in the left float, until it was repaired at the last annual inspection. See attached statements. AIRCRAFT INFORMATION At the accident site, the airplane's hour meter, contained within the RPM gauge, was indicating 3,044.5 hours. Examination of the maintenance records revealed that the most recent annual inspection of the engine and airframe, was accomplished on October 28, 1999, 57 hours before the accident. The engine had accrued a total time in service of 3,044.5 hours. The maintenance records note that a major overhaul was accomplished on October 10, 1983, 1,529 hours before the accident. METEOROLOGICAL INFORMATION The closest official weather observation station is Klawock, Alaska, which is located 22 nautical miles southwest of the accident site. On July 20, 2000, at 1853, an automated surface observation system (ASOS) was reporting in part: Wind, 210 degrees (true) at 5 knots; visibility, 10 statute miles; clouds and sky condition, clear; temperature, 61 degrees F; dew point, 48 degrees F; altimeter, 30.06 inHg. COMMUNICATIONS There were no reports of communications with the accident airplane. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board investigator-in-charge (IIC) and a Federal Aviation Administration (FAA) inspector examined the airplane wreckage at the accident site on July 21, 2000. The accident site consisted of thick forested terrain with trees extending upwards of 30 feet. The forest floor had numerous large fallen tree trunks and limbs, and soft, moss-covered ground. The entire wreckage was found in a small opening in the trees, with all of the airplane's major components located at the main wreckage area. Examination of the trees surrounding the scene revealed no broken tree tops. Vertical scrape marks were visible on tree bark next to the scene. The fuselage came to rest in a near vertical, nose down attitude. It was extensively twisted and buckled. The engine and propeller were buried in the ground. The empennage, aft of the vertical stabilizer attach point, was bent aft and downward about 90 degrees, coming to rest in a nearly horizontal position, and resting about 15 feet above the cockpit and instrument panel. The cockpit area was crushed aft, with the floor of the cabin, aft of the rear door post, buckled upward. The left wing had extensive spanwise leading edge aft crushing. It was displaced aft from its normal position. At the point of rest, the left wing was oriented in a near horizontal position. It was buckled in a "U" shape, about mid-span, and draped over a large fallen tree trunk. The landing light assembly, normally installed in the leading edge of the left wing, was broken from its attach point and was lying on the ground, about 5 feet below the left wing point of rest. The left wing flap and aileron remained attached to the wing. The right wing came to rest in a near vertical, leading edge down, position. The leading edge had extensive spanwise aft crushing, with semicircular aft crushing around a large tree stump, between the wing lift strut attach point and the wing tip. The wing material was crushed aft to the wing spar and extensively shredded. The right wingtip cap remained attached to the wing. The right wing flap and aileron remained attached to the wing. The empennage was resting above the vertically oriented fuselage. The rudder remained attached to the vertical stabilizer, and each had minor damage. The elevator remained attached to the horizontal stabilizer. The leading edge of the left horizontal stabilizer had aft spanwise crushing. The outboard end of the left elevator was bent upward. The float struts and spreader bars were torn away from the fuselage. The left float assembly, still attached to the float struts, was located under the empennage. It was extensively twisted and buckled, with upward and aft bending of the nose of the float. The right float assembly was torn from its attach points on the strut/spreader bars. The rear half of the float was torn off the float assembly. It was found on the left side of the cabin, under the left wing. The forward half of the right float was lying about 5 feet to the right of the fuselage point of rest, at the base of a large tree. It had extensive aft crushing and buckling. Disruption of the tree bark was visible above the float, extending vertically up the tree about 10 feet. Due to the impact damage, the flight controls could not be moved by their respective control mechanisms. The continuity of the flight control cables from the wings was established to the cabin area. The accident scene had a pronounced odor of gasoline. Fuel was pooled under the wreckage and was trickling downhill from the accident site. The engine was buried in the ground on about a 30 degree nose down attitude, with about a 80 degree left bank. The propeller assembly was buried in ground and was not visible. The right engine cylinders were visible above the ground, as were the right side exhaust tubes. The exhaust tubes were bent and folded at the point where the collector tubes were joined together. The folded metal of the tube had sharp creases that were not cracked or broken along the crease. The remaining portions of the engine were not visible. No evidence of any preimpact mechanical anomalies were discovered during the on-site investigation. MEDICAL AND PATHOLOGICAL INFORMATION A postmortem examination of the pilot was conducted under the authority of the Alaska State Medical Examiner, 5700 E. Tudor, Anchorage, Alaska, on July 24, 2000. The cause of death for the pilot was attributed to multiple blunt force impact injuries. A toxicological examination was conducted by the FAA's Civil Aeromedical Institute (CAMI) on September 7, 2000. The examination was negative for any drugs. The presence of ethanol was found in samples of blood and urine. The CAMI toxicological reported noted that the ethanol may potentially be from postmortem ethanol production, and not from the ingestion of ethanol. WRECKAGE RELEASE The Safety Board did not take custody of the wreckage. The wreckage was not recovered. No parts or components were retained by the Safety Board.

Probable Cause and Findings

The pilot-in-command's inadvertent stalling of the airplane.

 

Source: NTSB Aviation Accident Database

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