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N733SW accident description

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Tail numberN733SW
Accident dateOctober 03, 2001
Aircraft typeCessna 172N
LocationDecatur Island, WA
Near 48.5 N, -122.808056 W
Additional details: None

NTSB description

HISTORY OF FLIGHT

On October 3, 2001, about 1338 Pacific daylight time, a Cessna 172N, N733SW, was substantially damaged after colliding with forested terrain approximately 1,300 feet north of the Decatur Shores Airstrip, Decatur Island, Washington. The airplane is owned by Aeronautical Services, Inc, and was being operated as West Isle Air flight 125. The airplane was being operated as a visual flight rules (VFR) scheduled, passenger flight under the provisions of Title 14, CFR Part 135, when the accident occurred. The pilot, an airline transport pilot, and the two passengers aboard the airplane were fatally injured. Visual meteorological conditions prevailed and a company flight plan was in effect. The pilot's planned destination was Anacortes, Washington.

Witnesses to the accident reported that shortly after departing from the northbound runway, the pilot initiated a 360-degree turn to the right (east). Shortly before completing the turn, the aircraft banked sharply to the left, pitched down, and collided with trees in a nose-low attitude. Witnesses reported that the aircraft's engine sounded normal during takeoff and the initial climb.

PERSONNEL INFORMATION

The pilot held an airline transport pilot (ATP) certificate with an airplane multiengine land rating. He also held a commercial pilot certificate with an airplane single-engine land rating and instrument rating. According to company training records, the pilot's most recent proficiency check was completed on June 12, 2001, in a Piper PA-31-350.

According to FAA records, the pilot was issued a first-class medical certificate on August 28, 2001. The medical certificate carried no limitations or waivers. On the application for the medical certificate, the pilot indicated that he had accumulated approximately 3,100 total flight hours, including 140 hours in the six months preceding the application date.

AIRCRAFT INFORMATION

The airplane, a 1977 Cessna 172N (serial number 17268521), was powered by a naturally aspirated Lycoming O-320 series engine rated at 160 horsepower. Maintenance records indicated that the airplane's last inspection, a 100-hour inspection, was completed on September 10, 2001. The airplane had accumulated approximately 48 hours from the time of the inspection to the time of the accident.

According to the aircraft's flight manual, the maximum gross takeoff weight for the airplane is 2,300 pounds. Weight and balance records for the airplane, dated October 28, 1998, listed the airplanes empty weight as 1,426.2 pounds. The estimated gross weight of the airplane at takeoff was 2,361 pounds. The weights used to determine the airplane's gross weight at takeoff was based on the most current weight and balance records, the actual weights of the occupants (attached), the baggage and personal items (153 pounds) and the airplane's fuel load (102.6 pounds) at takeoff.

METEOROLOGICAL INFORMATION

The 1353 Aviation Routine Weather Report (METAR) at Friday Harbor, Washington (FHR), approximately 9 miles west of the accident location, reported winds from 348 degrees at 5 knots; visibility 10 statute miles; clear skies; temperature 16 degrees Celsius; dew point 8 degrees Celsius and altimeter setting 30.20 inches.

WRECKAGE AND IMPACT INFORMATION

Personnel from the NTSB, FAA, and Textron Lycoming accessed the aircraft wreckage on the morning of October 4, 2001. The wreckage was located in a heavily wooded area approximately 1/4 mile beyond the departure end of runway 33. The wreckage field encompassed an area approximately 195 feet long, from north to south. A grouping of large trees, with fresh scarring, was noted at the north end of the wreckage track. The magnetic bearing from the trees to the wreckage was approximately 170 degrees. The main wreckage was located at the southern most end of the wreckage distribution track. The remains of the fuselage were found inverted, oriented on a magnetic heading of 208 degrees. Evidence of a small post-crash fire was noted, with thermal damage and soot in the area of the carburetor.

All aircraft components were located at the crash site. The main wreckage consisted of the fuselage, empennage, right wing assembly and engine. A section of the left inboard wing and left flap was located approximately 18 feet north of the main wreckage. The remaining (outboard) section of the left wing and left aileron were located at the base of a large tree 100 feet north of the main wreckage. The still-standing tree measured approximately 10 feet in diameter and was approximately 150 feet tall. Fresh scarring, approximately 70 feet up from the base of the tree, was noted. The left main landing gear assembly was located 196 feet north of the main wreckage. The left main landing gear assembly was found at the northern end of the wreckage distribution track.

Extensive impact damage and fragmentation was noted to the cockpit controls and instrumentation panel. The throttle control was full forward, the mixture control was in the full rich position and the carburetor heat control was in the cold (forward) position. The fuel selector was in the "both" position.

All fixed and movable empennage control surfaces remained attached in their respective positions. Rearward crushing and deformation was noted to the outboard section of the left horizontal stabilizer and left elevator. The right horizontal stabilizer was bent aft; however, the right elevator was intact and no deformation was noted. The vertical stabilizer and rudder sustained minimal impact damage. Control cable continuity was established from the empennage control surfaces to the cockpit.

The partially attached right wing was located with the main wreckage. The right flap and aileron were attached to the wing, and the flap was in the up position. Leading edge deformation, increasing toward the tip, was noted. An undetermined amount of fuel, blue in color, was noted in the right fuel tank.

The left wing was found separated into two sections. The inboard section of the wing sustained extensive impact damage and had separated from the fuselage at the wing attach points. The wing flap had separated from the wing, and was located in the area of the inboard section of wing. A large section of the leading edge was crushed rearward to the trailing edge of the wing, exposing the wing fuel tank. Leading edge rearward crushing and bending was noted to the outboard section of the wing. The left aileron was still attached to the outboard wing assembly.

The propeller assembly was found as a unit attached to the crankshaft flange. Rearward crushing was noted to the propeller spinner. Aft bending and chordwise scratching was noted to propeller blade "A". Propeller blade "B" was bent aft and chordwise scratching was noted.

The engine was found attached to the engine mount assembly and firewall. Minimal impact damage was noted to the frontal, lower and accessory area of the engine. Rocker arm, valve train and accessory gear continuity was established by rotating the engine's crankshaft by hand. All four cylinders developed pressure when the crankshaft was manually rotated. Internal examination of the piston cylinders, utilizing a lighted bore scope, revealed no evidence of a mechanical malfunction. The single drive magneto assembly and ignition harnesses sustained thermal damage, however, produced spark when the drive shaft was manually rotated. The Spark plugs were removed and normal operating wear patterns were noted.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy on the pilot was conducted by the Snohomish County Medical Examiner's Office, Everett, Washington, on October 4, 2001. According to the autopsy report, the pilot's cause of death was blunt force injuries of the head and chest. The manner of death was listed as accidental.

The FAA Civil Aeromedical Institute (CAMI), Oklahoma City, Oklahoma, conducted toxicology testing on the pilot. According to the postmortem toxicology report, results were negative for carbon monoxide, cyanide, and ethanol, legal and illegal drugs. See attached report for specific test results.

TESTS AND RESEARCH

On October 12, 2001, representatives from the NTSB, Cessna Aircraft and Textron Lycoming conducted an engine examination and teardown at the operator's hangar facility in Anacortes, Washington.

Disassembly and examination of the engine revealed no evidence of pre-impact malfunction or failure. The rocker arms and valve assemblies were intact and in their normal position. The crankshaft main bearings exhibited no evidence of bearing shift or scoring. The connecting rods moved freely on their respective journals. No lifter spalling, pitting or abnormal camshaft wear was noted. The engine oil pump gears were intact and in their normal position. The oil pump cavity was clear and the oil screens were free of contaminants.

ADDITIONAL INFORMATION

On March 20, 2002, the airframe, engine and associated components were released to Kern and Wooley, Los Angeles, California.

(c) 2009-2011 Lee C. Baker. For informational purposes only.