N3717Q

HISTORY OF FLIGHTOn June 9, 2017, at 1430 Pacific daylight time, a Beech 95-C55, N3717Q, impact heavily forested terrain near Mountain Ranch, California. The commercial pilot was fatally injured, and the airplane was destroyed. The pilot/owner operated the airplane as a Title 14 Code of Federal Regulations Part 91 personal flight. Marginal visual meteorological conditions prevailed in the area of the accident site and no flight plan was filed for the flight, which departed Del Mar Farms Airport (CN99), Patterson, California, at 1348 and was destined for Columbia Airport (O22), Columbia, California.

Radar track data for the accident flight indicated that the airplane departed CN99 about 1348 and flew directly toward O22, located about 46 nautical miles (nm) northeast. The airplane climbed and maintained an altitude of 2,600 ft mean sea level (msl) until it was about 4 nm from O22, which was located at an elevation about 2,120 ft msl. The data indicated that, at that point, the airplane began a climb, then turned northwest toward Calaveras County Airport/Maury Rasmussen Field (CPU), San Andreas, California, about 13 nm northwest of O22. The airplane climbed to 4,000 ft msl before entering a descent. The airplane continued in a right turn and data was lost at 1413:29 with the airplane on a northeast heading at an altitude of 3,649 ft msl about 1 nm north of the accident site. The pilot was not in contact with air traffic control during the accident flight.

An Alert Notice (ALNOT) was issued; the airplane was subsequently located by the Calaveras County Sheriff's Department on June 13, 2017. PERSONNEL INFORMATIONThe pilot held a commercial pilot certificate with ratings for airplane single- and multiengine land and instrument airplane. His most recent Federal Aviation Administration (FAA) second-class medical certificate was issued on April 5, 2017, with the limitation that he must wear corrective lenses for near and distant vision. On the application for that medical certificate, the pilot reported 5,136 total hours of flight experience with 70 hours in the previous six months.

The pilot's personal logbook was not available for review, as such the pilot's instrument currency was not determined. AIRCRAFT INFORMATIONAccording to the airplane's logbooks, the last annual inspection was completed on June 29, 2016, at a total airframe time of 3,920.9 hours. The left and right oil filters were dated January 26, 2017, with 3,937.3 total airframe hours. On March 3, 2017, the left main fuel cell and left auxiliary fuel cell were replaced. At that time, the logbook entry indicated 3,937.3 total airframe hours. METEOROLOGICAL INFORMATIONThe pilot received two weather briefings on the day of the accident. The first one was at 0457 and was an abbreviated briefing in which the pilot requested the current weather and Terminal Aerodrome Forecast (TAF), and winds aloft at 6,000 ft for Stockton Metropolitan Airport (SCK), Stockton, California; SCK was approximately 50 miles southwest of the accident site.

During the second weather briefing, at 1304, the pilot was provided with AIRMET advisories Tango and Sierra, as well as the current O22 METAR, winds aloft at 6,000 ft, and was advised that visual flight rules (VFR) flight was not recommended.

AIRMET advisories Tango and Sierra were issued at 1345 and valid at the time of the accident. AIRMETs Tango and Sierra forecast moderate turbulence below 18,000 ft and mountain obscuration conditions due to clouds and mist. Similar conditions existed for the accident site and along the intended route of flight.

Weather observations from area airports around the time of the accident indicated marginal visual flight rules (MVFR) to VFR conditions due to cloud ceilings, which varied between 1,000 ft and 3,300 ft above ground level (agl) (2,500 ft and 4,200 ft msl in the mountainous terrain along the flight path).

CPU, the closest official weather observation point, located 12 miles southwest of the accident site. The 1355 observation included wind from 060° at 6 knots, 10 miles visibility, scattered clouds at 900 ft agl, broken ceiling at 1,600 ft agl, overcast skies at 3,300 ft. agl, temperature 18°C, dew point 15°C, and an altimeter setting of 29.95 inches of mercury. The 1415 observation included wind from 020° at 3 knots, 10 miles visibility, scattered clouds at 900 ft agl, broken ceiling at 1,600 ft agl, overcast skies at 2,700 ft agl, temperature 18°C, and dew point 15°C, and an altimeter setting of 29.95 inches of mercury. The 1435 weather observation included wind from 330° at 3 knots, 10 miles visibility, scattered clouds at 1,600 ft, broken clouds at 2,900 ft, and overcast clouds at 6,500 ft, temperature 20°C, dew point 15°C, and an altimeter setting of 29.94 inches of mercury.

O22, the next closest official weather observation point, located 15 miles south of the accident site. The 1355 observation included wind from 240° at 3 knots, scattered clouds at 800 ft agl, a broken ceiling at 2,400 ft agl, overcast skies at 3,300 ft agl, temperature 18°C, dew point 14°C, and an altimeter setting of 29.99 inches of mercury. The 1435 observation included calm wind, scattered clouds at 1,300 ft agl, an overcast ceiling at 2,200 ft agl, temperature 18°C, dew point 14°C, and an altimeter setting of 29.98 inches of mercury.

The Area Forecast issued at 1245 and valid at the accident time forecast a broken ceiling at 3,500 ft to 5,000 ft msl with broken skies at 8,000 to 10,000 ft msl, and cloud tops at 18,000 ft. Isolated light rain showers were also forecast. AIRPORT INFORMATIONAccording to the airplane's logbooks, the last annual inspection was completed on June 29, 2016, at a total airframe time of 3,920.9 hours. The left and right oil filters were dated January 26, 2017, with 3,937.3 total airframe hours. On March 3, 2017, the left main fuel cell and left auxiliary fuel cell were replaced. At that time, the logbook entry indicated 3,937.3 total airframe hours. WRECKAGE AND IMPACT INFORMATIONThe airplane came to rest inverted on a southerly heading on a 65° slope at an elevation of 2,950 ft msl about 15 miles north of O22. The wreckage was in a forested and hilly area with fragmented pieces throughout the 500 ft debris path, which culminated at the top of an adjacent hill. The fuselage (instrument panel, seats, and cabin area), right engine, and portions of the right wing were identified near the top of a hill; the debris field extended downhill to the left wing and left engine. Several treetops between the two hills exhibited signatures consistent with impact. Vegetation in the immediate vicinity of the empennage and both wings was brown and discolored consistent with fuel blight.

Responding law enforcement reported a strong smell of fuel at the accident site.

The right wing had fragmented into multiple pieces; however, the right aileron and flap were present. The aileron control cable exhibited signatures consistent with overload. The right propeller assembly separated from the engine at the propeller flange, which was embedded in the side of the hill. The propeller assembly included all three propeller blades; the blades exhibited S-bending and torsional twisting. Both magnetos separated from the engine due to impact damage. The P-leads also sustained impact damage. The outboard 3 ft of the right wing was located about 10 ft east of the left wing and engine.

The left propeller assembly separated from the engine and was embedded in the ground downhill of the fuselage and uphill from the left engine. The propeller assembly included all three propeller blades, which exhibited S-bending and torsional twisting.

The empennage, which included portions of the horizontal and vertical stabilizers, rudder, and elevators was located downhill from the fuselage. The flight control cables, pulleys, and control tubes were continuous to the forward empennage. Separation signatures were consistent with overload.

The left engine and fragments of the left wing were located at the bottom of a hill adjacent to a dry creek bed. The left aileron and left flap were identified with leading edge skin damage that displayed accordion crushing from leading to trailing edge. The left main landing gear was found under the left flap assembly. The left engine came to rest inverted and exhibited impact damage with dirt and vegetation embedded in the engine. The exhaust tubing was separated and crushed. The outboard 3 ft of the left wing was located at the top of the adjacent hill.

The flap actuator measurement was consistent with a flaps-retracted position. The landing gear was consistent with a gear-retracted position.

Examination of the airframe revealed no mechanical anomalies that would have precluded normal operation.

Right Engine

A visual examination of the right engine revealed no obvious holes in the case. Both magnetos separated from the engine. The right magneto sustained impact damage and a functional check was not possible; the magneto was disassembled with no anomalies identified with the internal components. The left magneto remained intact and sparked at all leads when manually rotated.

The ignition harness sustained damage to all the leads. The spark plugs sustained impact damage and the bottom spark plugs were removed. The Nos. 4- and 6-cylinders top spark plug center electrodes were missing. According to the Champion Check-a-Plug Chart, the spark plugs exhibited a normal wear pattern. There were no signs of lead or carbon fouling of the electrodes.

Borescope examination of the cylinders revealed no stuck intake or exhaust valves, and operating signatures appeared normal. There was organic matter (dirt, tree fragments, and rocks) in the cylinders. The vacuum pump vanes remained intact and coated with residual oil. The drive shaft was manually manipulated and rotated without binding.

Left Engine

A visual examination of the left engine revealed no obvious holes in the case. Both magnetos ...