Aviation Accident Summaries

Aviation Accident Summary FTW01FA014

ROCKPORT, TX, USA

Aircraft #1

N6968G

Cessna 150L

Analysis

Airport personnel heard the student pilot of the single-engine airplane declare 'Mayday' and indicate that his engine was 'out.' The airplane wreckage was located in 2-foot-deep water 9 miles from the pilot's departure airport. All of the wreckage was submerged or partially submerged in salt water. The wreckage path measured approximately 275 feet in length. Examination of the wreckage indicated that the airplane impacted the water in a nose down attitude. No discrepancies were noted during the investigation that would have prevented normal engine operation.

Factual Information

HISTORY OF FLIGHT On October 26, 2000, approximately 1515 central daylight time, a Cessna 150L single-engine airplane, N6968G, was destroyed when it impacted water near San Jose Island near Rockport, Texas. The student pilot, who was the sole occupant, was fatally injured. The airplane was registered to a private individual and operated by Sky Park Aviation, Inc., of Sinton, Texas. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 solo instructional flight. The local training flight departed from the Arnasas County Airport (RKP) near Rockport, Texas, approximately 1345. According to personnel at RKP, the pilot topped off the fuel tanks with 3.28 gallons of fuel and departed on his local flight. One of the personnel stated that he thought the pilot was going to practice S-turns and stalls. Around 1515, the airport personnel heard the pilot broadcast "Mayday, Mayday, November 68 Golf, engine out" over the airport's common traffic advisory frequency. The RKP airport manager called Petroleum Helicopters Inc. (PHI), who operate in the area, and asked them to assist in the search effort. The RKP airport manager stated that a PHI helicopter located the airplane wreckage in the water near San Jose Island approximately 45 minutes after the mayday call. PERSONNEL INFORMATION The student pilot was issued a student pilot certificate on September 7, 1999. He was issued a third class medical certificate on that same date with the limitation: "must wear corrective lenses for near and distant vision." According to the pilot's logbook, he started his flight training on April 29, 1999, and had accumulated 56 hours of total flight time. AIRCRAFT INFORMATION The 1970-model, two-seat, single-engine airplane was last endorsed for an annual inspection on September 21, 2000, at an aircraft total time of 8,177.9 hours. At the time of the accident, the airplane had accumulated 8,213.83 hours. The Teledyne Continental O-200-A48 engine (serial number 231159-R) was factory remanufactured and zero timed in 1980. The engine was field overhauled in 1987 at an engine total time of 1,837 hours. In 1991, the engine received a top overhaul 1,034.1 hours after the 1987 overhaul. On January 6, 1993, the engine was installed on N6968G at a tachometer time of 6,048.1 hours. On September 9, 1993, the #4 cylinder was replaced "due to low compression," 56.9 hours after the 1991 top overhaul. The operator used "daily flight logs" to track flight times. On the back of the logs, pilots listed discrepancies noted during their flights. The FAA inspector and NTSB investigator-in-charge (IIC) conducted a review of the daily flight logs back to November 1999. There were numerous open discrepancies that had not been endorsed as repaired. The following is a list of engine related discrepancies and their repairs, if listed: November 28, 1999 Carburetor heat drops 350 RPM; No fix listed. January 8, 2000 Aircraft starter would not engage; No fix listed. March 23, 2000 Engine seems underpowered; No fix listed. March 23, 2000 Engine will not shutoff with mixture; No fix listed. March 24, 2000 Carburetor heat on and RPM dropped to 1,900 then never recovered; No fix listed. September 24, 2000 Solenoid problem, would not engage starter until cooled off; No fix listed. September 26, 2000 Starter won't engage; Fixed 10/2. October 22, 2000 RPM drops from 2400 to 2000 when carburetor heat is applied in the air; Maint. Checked. METEOROLOGICAL INFORMATION At 1451, the weather observation facility at the Corpus Christi International Airport, located 42 miles southwest of the accident site, reported the wind from 150 degrees at 15 knots, a scattered layer of clouds at 3,100 feet agl, visibility 10 statute miles, temperature 84 degrees Fahrenheit, dew point 66 degrees Fahrenheit, and an altimeter setting of 29.94 inches of Mercury. WRECKAGE AND IMPACT INFORMATION The aircraft wreckage was located approximately 9 miles east of the RKP airport. The wreckage distribution path originated at an impact crater and stretched approximately 275 feet and was oriented along a measured 240 degree magnetic course. All of the wreckage was either submerged or partially submerged in 2 feet of salt water. Located in the initial impact crater, which was submerged underwater, was the propeller, which was found separated from the engine. One of the propeller blades was bent aft approximately 60 degrees and both blades were twisted toward a lower pitch angle. Each blade displayed light rub marks near the tips, with the one blade that was bent aft displaying some leading edge gouges. The propeller spinner was compressed aft and flattened around the propeller hub. Also located in the impact crater were the nose landing gear strut, with the nose wheel separated, and segments of engine intake and exhaust manifolds. The main wreckage area consisted of the fuselage, which came to rest approximately 250 feet from the initial impact crater, and the left wing, which was separated from the fuselage and found laying adjacent to it. The empennage remained intact and was found adjacent to the main wreckage; however, it was also separated from the fuselage. The left wing's spar was twisted 360 degrees from the root to tip. The flap and aileron remained attached to the left wing; however, they too were twisted and deformed. The left horizontal stabilizer received leading edge damage and the vertical stabilizer was bent over near its base to the left. Sections of the left wing were found near the initial impact crater and along the entire wreckage distribution path. The right wing was separated from the fuselage at its root and was found approximately 35 feet prior to the fuselage's final resting area. The right wing's aileron was separated and half of its flap was separated. Both the left and right fuel tanks were separated from their respective wings, and were compromised. The cockpit was destroyed by impact forces, and the forward section of the fuselage displayed accordion type crushing aft. Both the left and right seats were found separated from the fuselage. Both the left and right control yokes were separated at the control lock area and were resting adjacent to the main wreckage area. The left horns on both control yokes were found separated. The cockpit engine controls were found in the full forward position. The fuel selector was found in the on position. The engine was separated from its mounts, but remained attached to the cockpit by the engine control cables. The carburetor, vacuum pump, and oil sump were separated from the engine and were found along the wreckage path. The engine could not be examined at the accident site. On October 29, 2000, the airplane wreckage was moved to a hangar located at RKP under the supervision of the NTSB IIC. The engine was examined by the NTSB IIC, a Teledyne Continental Motors representative, and a Cessna Aircraft representative. The spark plugs were removed and examined. They were covered in mud and corrosive material. The electrodes did not display any anomalies. The starter was then removed from the accessory section and examined. The starter gear rotated freely and retracted when released. The magnetos were removed from the accessory section and the gears were rotated manually. Both the left and right magneto magnets rotated freely and the impulse couplings functioned properly. The magneto's ability to produce a spark could not be verified due to water damage. The alternator was removed and its gear rotated freely. The accessory case was removed and the oil pump was examined. The oil pump rotated and oil was present around the gears. The gears displayed even wear marks. The oil screen was removed and was found soaked in oil and clean of debris. The crankshaft gear was rotated manually and crankshaft continuity was verified. The rocker arm covers were removed and rocker arm movement was verified on all 4 cylinders. Piston movement was also verified on all 4 cylinders. The carburetor was examined. The carburetor's butterfly valve was found in the full open position. Small foam-type debris (similar to the foam in an engine intake filter) was found in the carburetor's venturi; however, the debris was not large enough to block airflow to the engine. The carburetor was then disassembled. The metallic floats displayed hydraulic deformation. The accelerator pump was intact and its seal was present. The engine's inlet air filter was not found during the wreckage recovery. The FAA inspector examined the engine intake manifolds and intake valve areas and found no evidence of foam debris or blockage. PATHOLOGICAL INFORMATION An autopsy was conducted on the pilot at the Nueces County Medical Examiner's Office. According to the medical examiner, the pilot died as a result of multiple injuries. A toxicology test for carbon monoxide, cyanide, volatiles, and drugs was performed at the Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma. The toxicology test results were as follows: 23 mg/dL of ethanol detected in blood, 20 mg/dL ethanol detected in muscle; 4 mg/dL of acetaldehyde detected in the blood, 2 mg/dL acetaldehyde detected in the brain, 4 mg/dL of acetaldehyde detected in the muscle; 13 mg/dL of isopropanol detected in the muscle; 17 mg/dL of n-propanol detected in the muscle; and 10 mg/dL of methanol detected in the muscle. According to the CAMI report, "the ethanol found in this case may potentially be from postmortem ethanol formation and not from the ingestion of ethanol." ADDITIONAL INFORMATION The wreckage was released to the owner's representative on January 3, 2001.

Probable Cause and Findings

the loss of engine power for undetermined reasons, and the pilot's subsequent failure to maintain control of the airplane during the ensuing forced landing.

 

Source: NTSB Aviation Accident Database

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