Laytonville, CA, USA
N1186U
CESSNA 172M
The private pilot was conducting a local personal flight. Witnesses reported that they observed the airplane making several low passes over an open field. During the last pass, they observed the airplane's right wing contact a tree and then separate from the airplane. The airplane subsequently came to rest in a wooded area. According to the autopsy report, the pilot had coronary artery maximum occlusion of 50 percent, and there was no evidence of preexisting heart muscle scarring. This amount of occlusion likely would not have caused acute symptoms and would not have impaired the pilot's judgment; therefore, the pilot's coronary artery disease likely did not impair his ability to operate the airplane or contribute to the accident. Toxicology reports identified ethanol in the pilot's heart blood, iliac blood, vitreous, and urine. The distribution of the ethanol in the pilot's tissue was consistent with ingestion, not postmortem production. Although there was some variation, all of the pilot's tissues tested positive for ethanol well above 0.040 gram per deciliter, which indicates that the pilot had ingested sufficient ethanol to impair his ability to safety operate the airplane.
HISTORY OF FLIGHTOn June 5, 2014, about 1923 Pacific daylight time, a Cessna 172M, N1186U, collided with trees while maneuvering at low altitude near Laytonville, California. The pilot/owner was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot sustained fatal injuries. The airplane sustained substantial damage to the airframe and wings during the accident sequence. The local personal flight departed Laytonville at an undetermined time. Visual meteorological conditions (VMC) prevailed, and no flight plan had been filed. Witnesses reported that the airplane was at low level, and made several passes over an open field. During another pass, they observed the right wing make contact with a tree, and separate from the airplane. The airplane came to rest in a wooded area. PERSONNEL INFORMATIONA review of Federal Aviation Administration (FAA) airman records revealed that the 63-year-old pilot held a private pilot certificate with a rating for airplane single-engine land. The pilot held a third-class medical certificate issued on August 7, 2012. It had the limitation that the pilot must have glasses for near vision. No personal flight records were located for the pilot. The National Transportation Safety Board (NTSB) investigator-in-charge (IIC) obtained the aeronautical experience listed in this report from a review of the FAA airmen medical records on file in the Airman and Medical Records Center located in Oklahoma City, Oklahoma. The pilot reported on his medical application that he had a total time of 590 hours with 0 hours logged in the previous 6 months. AIRCRAFT INFORMATIONThe airplane was a Cessna 172M, serial number 17266887. No logbooks were made available for examination. At the wreckage examination, the tachometer read 1,194.4, and the Hobbs hour meter read 890.5. The engine was a Lycoming O-360-A4A that had been altered to an O-360-A4M, serial number L-30908-36A. AIRPORT INFORMATIONThe airplane was a Cessna 172M, serial number 17266887. No logbooks were made available for examination. At the wreckage examination, the tachometer read 1,194.4, and the Hobbs hour meter read 890.5. The engine was a Lycoming O-360-A4A that had been altered to an O-360-A4M, serial number L-30908-36A. MEDICAL AND PATHOLOGICAL INFORMATIONA postmortem examination was conducted by the Office of the Coroner – Mendocino County. The cause of death was reported as the effect of blunt force injuries. The Coroner had specimens from the pilot tested by NMS Labs, Willow Grove, Pennsylvania. The toxicology test identified 217 mg/dL of ethanol in the iliac blood. The FAA Civil Aerospace Medical Institute Forensic Toxicology Research Team, Oklahoma City, performed toxicological testing of specimens of the pilot. Analysis of the specimens contained no findings for carbon monoxide or tested drugs. They did not perform tests for cyanide. The report contained the following findings for volatiles: 274 (mg/dL, mg/hg) ethanol detected in urine, 237 (mg/dL, mg/hg) ethanol detected in vitreous; and 172 (mg/dL, mg/hg) detected in blood (heart). An NTSB Medical Officer examined the pilot's medical records, and provided a factual report. The report is part of the public docket for this accident, which is accessible via a link on the ntsb.gov home page. On the most recent medical exam dated August 7, 2012, the pilot reported a history of a driving under the influence (DUI) arrest on March 22, 2012. The records indicated a previous alcohol related arrest in 1990. Ethanol is the intoxicant commonly found in beer, wine, and liquor; it acts as a central nervous system depressant. The distribution pattern parallels the water content and blood supply of each organ. Ethanol may also be produced in the body after death by microbial activity, but urine and vitreous are less prone to postmortem changes. After ingestion, at low doses it impairs judgment, psychomotor functioning, and vigilance; at higher doses it can cause coma and death. The effects of ethanol on aviators are generally well understood; it significantly impairs pilots' performance, even at very low levels. Federal Aviation Regulations, Section 91.17 (a) prohibits any person from acting or attempting to act as a crewmember of a civil aircraft while having 0.040 gm/dL or more ethanol in the blood. The autopsy identified coronary artery disease with up to 40% narrowing of the proximal left anterior descending artery and diffuse 25 to 50% narrowing of the mid portion of the right coronary artery. It did not identify focal lesions the heart muscle. TESTS AND RESEARCHInvestigators from the NTSB, the FAA, Cessna, and Lycoming examined the wreckage at Air Transport, Phoenix, Arizona, on July 16, 2014. A full report is in the public docket for this accident, which is accessible via a link on the ntsb.gov home page. The airframe and engine were examined with no mechanical anomalies identified.
The pilot’s impairment due to alcohol ingestion, which resulted in his failure to maintain clearance from trees during a low-altitude flyby.
Source: NTSB Aviation Accident Database
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