WPR17FA125

The pilot's continued visual flight rules flight into instrument meteorological conditions and mountain obscuration that resulted in controlled flight into trees and terrain.

The instrument-rated commercial pilot departed on a 46-nautical-mile visual flight rules (VFR) flight in the multiengine airplane. Radar data indicated that, as the airplane approached the destination airport at an altitude about 500 ft above ground level, it turned northwest and climbed and appeared to be heading toward a nearby airport. The airplane then entered a right turning descent. The final radar target associated with the airplane was at 3,649 ft mean sea level (about 700 ft agl) about 1 nautical mile north of the accident site. The pilot received two weather briefings before departing on the accident flight, the second about 45 minutes before departure. During the second briefing, the pilot was provided AIRMETs Tango and Sierra for moderate turbulence and mountain obscuration due to clouds and mist, valid for the route of flight and the area of the destination airport.  The pilot was also advised during this briefing that VFR flight was not recommended. Review of weather information revealed the presence of multiple cloud layers in the area of the accident site around the time of the accident, including scattered clouds at 1,600 ft above ground level (agl), a broken ceiling at 2,900 ft, and an overcast ceiling at 6,500 ft. Despite the forecasts indicating marginal VFR conditions for the destination airport, the pilot chose to depart and continue into an area of low cloud ceilings and rising terrain. It is likely that, while maneuvering at low altitude, the terrain was obscured or the pilot's in-flight visibility was limited by the cloud conditions, which resulted in controlled flight into terrain. Witness marks in the trees and damage to the airplane were consistent with a controlled flight into terrain event. The airframe and engine examination revealed no mechanical anomalies that would have precluded normal operation. The toxicology report yielded positive findings for ethanol and for citalopram, a prescription antidepressant. It is likely that some of the ethanol was the result of postmortem production; however, due to limited tissue specimens, whether some of the ethanol was from ingestion or if it impaired the pilot could not be determined. It is unlikely that the pilot's use of citalopram resulted in impairment, but whether the pilot was impaired by the effects of depression could not be determined. Additionally, due to the extent of injury, autopsy was unable to determine if the pilot had any potentially impairing natural disease. Through a review of the pilot's FAA certified medical information, it was determined that the pilot was instrument rated. However, the pilot's logbook was not available, and investigators were not able to determine the pilots instrument currency.

The Forensic Consultant's Medical Group, Inc., Stockton, California, performed the autopsy of the pilot. The cause of death was reported as multiple blunt force injuries; the autopsy was limited due to the extent of injury. Toxicology testing performed at the FAA Forensic Sciences Laboratory identified 93 mg/hg ethanol (equivalent to 0.093 gm/dl), isopropanol, N-Butanol, and citalopram in muscle tissue. The detected ethanol could have been from ingestion of alcohol or a byproduct of microbial activity after death. The pilot reported on his most recent application for a medical certificate that he had high blood pressure that was controlled without medications and reported no other medications. Citalopram, marketed as Celexa, is a prescription antidepressant not known to directly cause sleepiness or other impairing symptoms. No further records from the pilot's treating physician were obtained. The 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. The 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. According 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. The 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