Aviation Accident Summaries

Aviation Accident Summary WPR13FA083

Oceano, CA, USA

Aircraft #1

N45923

LUSCOMBE 8A

Analysis

Witnesses reported that they observed the airplane flying low above the beach before it ascended abruptly. When the airplane was about 150 to 200 feet above the ground, the ascent stopped, and the airplane then descended in a nose low attitude to ground impact. Witnesses also reported that the engine sounded normal during the accident sequence. Postaccident examination of the airframe and engine revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation. The pilot had a reported history of marijuana abuse. Toxicology testing on the pilot was positive for tetrahydrocannabinol at levels that indicate he was likely impaired during the flight. This impairment likely affected the pilot's ability to maintain airplane control and his decision to begin a low-level flight maneuver at an altitude that was not sufficient for recovery before impact with the ground.

Factual Information

HISTORY OF FLIGHTOn January 2, 2013, about 1605 Pacific standard time, a Luscombe 8A, N45923, was substantially damaged when it impacted terrain about 2 miles south of the Oceano County Airport (L52), Oceano, California. The commercial pilot was fatally injured. The airplane was registered to, and operated by, the pilot as a 14 Code of Federal Regulations (CFR) Part 91 local personal flight. Visual meteorological conditions prevailed and no flight plan was filed. The flight originated from L52 at an unknown time. Witnesses reported that they observed the airplane flying low above the beach when it ascended abruptly. When the airplane was approximately 150-200 feet above the ground, it appeared to stop and descended abruptly before it impacted the sand dunes below. The witnesses did not see the initial impact, but they observed the airplane bounce. Witnesses reported that the engine sounded normal during the accident sequence. PERSONNEL INFORMATIONAt the time of the accident, the pilot, age 56, held a commercial pilot certificate with airplane single- and multi-engine land privileges. The pilot also held an airframe and powerplant mechanics certificate. The pilot's most recent Federal Aviation Administration (FAA) second class medical was issued on October 1, 2012 with the restriction that he must possess glasses for near and intermediate vision. During his examination, the pilot reported he had a total of 7,000 flight hours, 185 of which were within the six months preceding the examination. The pilot's logbooks were not located. AIRCRAFT INFORMATIONThe two-seat, high-wing, fixed-gear airplane, serial number 2450, was manufactured in 1946. It was powered by a Continental Motors A-65-8, 65 horsepower engine and was equipped with a fixed-pitch propeller. The airplane's maintenance logbooks were not located. METEOROLOGICAL INFORMATIONThe nearest weather reporting station, San Luis Obispo Regional Airport (SBP), located approximately 10 miles north of the accident site reported at 1756, calm wind, 10 statute miles of visibility, clear skies, temperature 17 degrees C, dewpoint -6 degrees C, and an altimeter reading of 30.08 inches of mercury. AIRPORT INFORMATIONThe two-seat, high-wing, fixed-gear airplane, serial number 2450, was manufactured in 1946. It was powered by a Continental Motors A-65-8, 65 horsepower engine and was equipped with a fixed-pitch propeller. The airplane's maintenance logbooks were not located. WRECKAGE AND IMPACT INFORMATIONThe wreckage debris path was approximately 720 feet long with a heading of about 19 degrees. The first identified point of impact was a divot on the ridge of a sand dune that was consistent with a tire mark. Almost immediately following the initial point of impact was an about 8 foot by 3 foot section of heavily disrupted sand, with three foot wide sliding marks extending toward an approximate 2 foot by 6 inch impact point. After the impact point, there was about 7 feet of undisturbed sand followed by the main wreckage, which was a total of about 120 feet beyond the first point of impact. The final piece of debris was a wheel that was located about 600 feet beyond the main wreckage on the other side of a second sand dune. Examination of the main wreckage revealed that the airplane came to rest in a nose low attitude. The forward fuselage sustained extensive crush damage, and the cabin area came to rest on top of the engine. The aft fuselage and empennage were still attached by the airplane's belly skin; however, it was folded underneath the airplane's wings and came to rest inverted in the sand. The empennage sustained minimal damage. The left and right horizontal stabilizers had a different paint scheme from the rest of the yellow empennage and airframe. The wings were still attached to the cabin and mostly intact; both wings sustained leading edge crushing throughout. Evidence of corrosion was noted at the wing spar attachment points and scattered throughout the remainder of the airframe. Flight control continuity was established from the cockpit controls to their respective flight control surfaces. MEDICAL AND PATHOLOGICAL INFORMATIONThe autopsy was performed on the pilot by the San Luis Obispo County Sheriff – Coroner Office in San Luis Obispo, California. The cause of death was sharp force injury and the autopsy noted that the pilot had an enlarged heart. Toxicology testing detected tetrahydrocannabinol in lung (0.0485 ug/ml), liver (0.011 ug/ml), and blood (0.0062 ug/ml). Tetrahydrocannabinol carboxylic acid, was detected in urine (0.0965 ug/ml), liver (0.0369 ug/ml), blood (0.0067 ug/ml), and lung (0.0053 ug/ml). The pilot had a history of cannabis abuse with a positive Department of Transportation required random test in 1999. The FAA had evaluated his history and determined him to be eligible for a second class medical certificate in 2003 and thereafter. Although additional random drug tests were recommended, they were not performed. For more detailed information see the Medical Factual Report located in the accident docket. TESTS AND RESEARCHEngine Examination The engine was removed from the firewall and slung from a hoist. Initial visual inspection of the recovered engine revealed no visual anomalies. The cylinder rocker covers and spark plugs were removed; the spark plug electrode areas were consistent with 'worn out - normal' when compared to the Champion AV-27 chart. The valves were undamaged and contained no abnormal thermal discoloration. When the propeller was rotated by hand, thumb compression was established on all cylinders, all valves moved in sequence and had similar amounts of lift, and the accessory gears rotated. The carburetor was fracture separated at the throttle plate neck; both pieces of the carburetor were removed from the engine. Sand was found inside of the carburetor and was consistent with the sand on scene. Both the throttle and mixture levers moved freely from stop to stop when manipulated by hand. The carburetor bowl was removed; there was no fuel in the carburetor bowl or the undamaged metal float. The oil screen was removed and contained some carbon flakes.

Probable Cause and Findings

The pilot’s failure to maintain airplane control and his improper decision to begin a low-level maneuver at an altitude that was not sufficient for recovery before ground impact. Contributing to the accident was the pilot’s impairment from marijuana use.

 

Source: NTSB Aviation Accident Database

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