Datil, NM, USA
N1548Y
Beech A36
Approximately 45 minutes into the cross-country flight, the airplane collided with hilly terrain during daytime hours in visual meteorological conditions. Examination of the airframe, engine, and propeller revealed no anomalies that precluded normal operation prior to impact. Postmortem examination of the pilot revealed atherosclerotic cardiovascular disease with severe blockage of the coronary arteries, and a clot noted in the left anterior descending artery. The autopsy report stated, "...the presence of significant atherosclerotic narrowing of the left anterior descending artery may have precipitated an abnormal heart rhythm (dysrhythmia) producing an incapacitating event during flight that resulted in the crash."
HISTORY OF FLIGHT On November 8, 2005, approximately 1230 mountain standard time, a Beech A36 single-engine airplane, N1548Y, was destroyed when it collided with terrain on the Double H Ranch near Datil, New Mexico. The private pilot, who was the sole occupant, sustained fatal injuries. The airplane was registered to and operated by the pilot. Visual meteorological conditions prevailed, and a flight plan was not filed for the Title 14 Code of Federal Regulations Part 91 personal flight. The flight departed Block Ranch Airport (4AZ2), Capitan, New Mexico, approximately 1145, and was destined for Phoenix Deer Valley Airport (DVT), Phoenix, Arizona. According to the Block Ranch manager, the pilot departed for Phoenix approximately 1145 from the ranch airstrip. The pilot flew over the ranch residence and then departed toward the west. The manager reported no anomalies with the airplane during the takeoff or when it flew over the residence. Approximately 1300, a Double H ranch hand noticed a fire on a hillside in the northwest corner of the ranch property. The ranch hand informed the Double H ranch manager of the fire, and they responded to the site. Upon reaching the fire location, the ranch manager realized the fire had been started as a result of an airplane accident. The ranch manager then contacted the United States Forest Service (USFS), Magdalena, New Mexico, and the New Mexico State Police. The USFS responded to the accident site and extinguished the fire. PERSONNEL INFORMATION The 77-year old pilot held a private pilot certificate with airplane single-engine land, airplane multi-engine land, and instrument airplane ratings. The pilot was issued a third-class medical certificate on February 28, 2005, with the limitations: "Must wear corrective lenses for near and distant vision. Not valid for any class after February 28, 2006." According to the Federal Aviation Administration's (FAA) medical records, on March 10, 2005, the pilot's medical certificate was suspended due to a history of glaucoma with visual field defect left eye. On June 6, 2005, the pilot successfully completed a FAA medical flight test, and the pilot received a third-class medical certificate. The pilot reported no "heart or vascular trouble" on any previous medical applications. The pilot's logbooks were not located; however, according to the pilot's February 28, 2005, medical application, the pilot reported a total time of 11,010 hours and 100 hours in the past 6 months. On January 21-23, 2005, the pilot completed a Beech Pilot Proficiency Program Approved Bonanza Recurrent Course. AIRCRAFT INFORMATION The 1989-model Beech A36, serial number E-2483, was a low wing, retractable landing gear, semi-monocoque design airplane. The airplane was powered by a six-cylinder, direct drive, air cooled, horizontally-opposed, fuel injected Teledyne Continental Motors IO-550-B engine (serial number 297185-R), rated at 300 horsepower, and equipped with a McCauley three-bladed constant speed propeller. The airplane was configured to carry a maximum of six occupants, and the maximum gross weight for the airplane was 3,650 pounds. The airplane was issued a standard airworthiness certificate and was certificated for normal category operations. The airplane's current registration was issued to the pilot on July 2, 2002. Complete airframe, engine, and propeller logbooks were not located; however, charred remnants of airplane maintenance records were found in the airplane wreckage. According to the maintenance facility that completed the last annual and 100-hour inspections on May 26, 2005, the airframe and engine had accumulated total times of 3,404.8 and 336.6 hours, respectively. The total airframe and engine times at the time of the accident could not be determined. METEOROLOGICAL INFORMATION Approximately 1045, the pilot obtained a weather briefing from the Albuquerque Flight Service Station. According to the weather brief audio recording, the briefer informed the pilot that the weather along the pilot's intended route of flight was clear below 12,000 feet msl and visibility was unrestricted. The briefer stated the pilot may experience moderate turbulence near Socorro, New Mexico (located approximately 50 east of the accident site) below 18,000 feet msl. The winds aloft near Socorro at 9,000 feet msl were from 280 degrees at 11 knots, and at 12,000 feet msl, were from 260 degrees at 28 knots. According to employees of the Double H ranch, at the time the accident site was located, the sky was clear and the wind was calm. WRECKAGE AND IMPACT INFORMATION The accident site was located in hilly and rocky terrain on the northwest corner of the Double H ranch property, approximately 10 miles northeast of Datil. Examination of the accident site revealed the airplane impacted terrain on a measured magnetic heading of 255 degrees at an elevation of 7,676 feet msl. The Global Positioning System coordinates recorded at the accident site were latitude North 34 degrees 22.608 minutes and longitude West 107 degrees 43.732 minutes. Examination of the accident site revealed the left wing impacted the tops of pinion pine trees prior to impact with terrain. The outboard portion of the right wing came to rest entangled in a pinion pine adjacent to the initial ground scar. Measurements of the pinion pine tree cuts at the initial impact indicated the airplane impacted the vegetation in a 3 degree nose down and 10 degree right wing down attitude. Navigation antennas, mounted on the underside of the fuselage, were located in the initial impact ground scar. Airplane debris fanned outward from the initial ground scar to the main wreckage and was distributed on rising terrain. The incline of the rising terrain measured approximately 19 degrees. The debris field contained sections of the left and right wings, engine cowling, engine accessories, one propeller blade, and broken sections of the windscreen. The main wreckage came to rest upright on a measure magnetic heading of 205 degrees and was located approximately 136 feet from the initial ground scar at an elevation of 7,720 feet msl. The main wreckage consisted of the fuselage, portions of the left and right wings, the empennage, and the engine. The main wreckage was destroyed by a post-impact fire. The inboard portion of the left wing remained attached to the fuselage and partially consumed by fire. The flap and inboard section of the aileron remained attached to the wing, and the outboard section of the aileron was separated and located in the debris field. The flap actuator and its attach points were consumed by fire. The trailing edge of the flap was intact. The left main landing gear remained partially attached to the wing structure and was in the retracted position. The inboard portion of the right wing with the flap attached, remained attached to the fuselage, was bent aft and partially consumed by fire. The outboard portion of the right wing with the aileron attached, was located in a pinion pine adjacent to the initial impact. The flap actuator and its attach points were consumed by fire. The trailing edge of the flap was intact. The right main landing gear remained partially attached to the wing structure and was in the retracted position. The empennage remained partially attached to the fuselage. The vertical stabilizer remained partially attached to the empennage and exhibited fire damage. The rudder remained attached to the vertical stabilizer and exhibited fire damage. The left horizontal stabilizer was intact and displayed damage to the leading edge. The left elevator remained attached to the horizontal stabilizer. The right horizontal stabilizer and elevator were consumed by fire, and the control cable and rod terminating ends were located at the position of the right elevator. Measurement of the left and right actuators corresponded to a neutral trim setting. The fuselage, cabin, and instrument panel were destroyed by fire. The airspeed indicator was partially consumed by fire and the needle was found folded over. When the needle was bent back straight, the needle pointed to 135 to 140 knots airspeed. Four seat frames were located in the fuselage. The left front seat restraint system was found in the engaged position. The cabin door was partially consumed by fire, and the door latch mechanism was found in the engaged position. The landing gear actuator was found in the retracted position. Control continuity was established from the control column to the left and right aileron and elevator bell cranks. Continuity was established from the rudder control bell crank to the rudder assembly bell crank. Continuity of the flap flex cable was established from the cockpit to the flap actuators. The engine was separated from its respective engine mounts, and was found adjacent to the main wreckage in an inverted position. The number 1 cylinder exhibited thermal damaged. The number 5 and 6 cylinder valve covers displayed thermal damage. The intake, exhaust, and muffler were crushed and fragmented. The oil sump was crushed and partially consumed by fire exposing internal engine components. The starter was separated and located in the debris field. The vacuum pump, propeller governor, alternator/generator, and magnetos exhibited thermal damage. The propeller hub remained attached to the engine crankshaft. One propeller blade was separated from the hub and located in the debris field 45 feet from the initial ground scar. The blade displayed leading edge gouges and chord wise scratches. Two blades remained secure in the propeller hub and exhibited thermal damage. The blades displayed leading edge damage and chord wise scratching. One blade was bent approximately 90 degrees aft, and the blade tip was separated. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot by the Office of the Medical Investigator, The University of New Mexico, Health Services Center, Albuquerque, New Mexico, on November 9, 2005, and specimens were retained for toxicological analysis by the FAA Civil Aeromedical Institute's (CAMI) Forensic and Accident Research Center, Oklahoma City, Oklahoma. According to the autopsy report, Internal Examination, Cardiovascular System section, "The coronary arteries arise normally and show significant, approximately 90 [percent] narrowing of the left anterior descending artery with atherosclerotic plaque. Focally, there is a thrombus within the artery." According to the autopsy report, Microscopic Examination, Heart section, "Sections of the coronary arteries show up to 95 [percent] narrowing by calcified atherosclerotic plaques." According to the autopsy report, Opinion section, "...Examination of the heart revealed significant narrowing of one of the blood vessels that supplies blood to the hear muscle (left coronary artery) by atherosclerotic plaques. The decedent died of the extensive injuries he would have sustained during the plane crash. However, the presence of significant atherosclerotic narrowing of the left anterior descending artery may have precipitated an abnormal heart rhythm (dysrhythmia) producing an incapacitating event during the flight that resulted in the crash." Toxicological tests were negative for ethanol and all screened drugs. Toxicological tests were not performed for carbon monoxide and cyanide. TEST AND RESEARCH On January 19, 2006, at the facilities of McCauley Propeller Systems, Wichita, Kansas, the propeller was examined under the supervision of the NTSB investigator-in-charge (IIC), and representatives of the airframe, engine, and propeller manufacturers. Examination of the propeller revealed no pre-impact anomalies with the propeller prior to impact. Damage to the blades, hub, and internal components was consistent with the propeller being operated under conditions of power at the time of impact; exact amount of power was not determined. Measurement of the piston position within the cylinder corresponded with a blade angle position of approximately 20.6 degrees, which was within operating limits of the propeller. On February 16, 2006, at the facilities of Air Transport, Phoenix, Arizona, the engine was examined and disassembled under the supervision of the NTSB IIC, and representatives of the airframe and engine manufacturers. Examination of the engine revealed thermal damage to the cylinders, gearbox, crankcase, and accessories. The magnetos were destroyed by fire and could not be functionally tested. The ignition harness was destroyed by fire. The number 1 cylinder lower spark plug was not located, and the upper spark plug was partially consumed by fire. The remaining spark plugs were removed and according to the Champion Spark Check-A-Plug chart AV-27, the spark plug electrodes displayed coloration consistent with normal operation. The fuel pump displayed thermal damage and was not free to rotate. The fuel manifold valve cover was removed and contained burnt debris consistent with the manifold diaphragm. The throttle body was destroyed. The oil sump was partially consumed by fire, and no oil was present in the engine. Disassembly of the engine revealed the cylinder combustion chambers and barrels were undamaged and no evidence of foreign debris or detonation was noted. The exhaust and intake valves were intact and undamaged. The pistons and piston rings were intact. The crankshaft and connecting rods were undamaged. The crankshaft counterweights were secure and intact. The camshaft was intact and undamaged. Mechanical continuity of the rotating components and internal mechanisms was established. No evidence of lubrication depravation or contamination was noted. ADDITIONAL INFORMATION The aircraft wreckage was released to the owner's representative on March 21, 2006.
the pilot's loss of control during flight as a result of incapacitation due to atherosclerotic cardiovascular disease.
Source: NTSB Aviation Accident Database
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