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On February 19, 2010, at 1917 Pacific standard time, a Piper PA-32R-301T, N4175A, collided with terrain in a residential area near Groveland, California. The pilot operated the airplane under the provisions of Title 14 Code of Federal Regulations Part 91. The certificated private pilot and passenger were killed. The airplane was substantially damaged by impact forces, and the fuselage was consumed in a post crash fire. The cross-country personal flight departed San Carlos Airport, San Carlos, California, about 1825, with a planned destination of Pine Mountain Lake Airport, Groveland. Night instrument meteorological conditions prevailed at the accident site, and no flight plan had been filed.
A witness who was located in a north-facing-room in his residence, directly adjacent to the accident site, heard a sound that appeared to be emanating directly above his house. He described the sound as similar to an engine running at full power. He was concerned that someone was "buzzing" his house. He looked out of the window and a few seconds later observed an explosion about 300 feet to the northeast in his neighbor’s yard. He reported light rain and mist to be present at the time of the accident.
A second witness, located 1/2 mile northeast of the approach end of runway 27, heard a low flying airplane, which he presumed was flying directly over his house. He described the sound as similar to an engine running "full bore." He immediately ran onto his deck, and a few seconds later observed a fireball erupt in the valley below. He stated that he normally has a full view of the airport beacon from his house, and that at the time of the accident the beacon was partially obscured by mist. He additionally reported that from his vantage point the area of the explosion was enveloped with clouds.
First responders from the sheriff's department, and additional witnesses, all reported similar weather conditions at the accident site including light rain, mist, and low clouds.
A pilot, who stated that he flies to the airport most weekends, reported attempting to land a Cessna 510 while on an instrument flight plan, about 1 hour prior to the accident. Throughout the instrument approach he was unable to identify the runway environment, and as such he performed a missed approach, diverting to Modesto where he landed uneventfully. He reported having flown into Pine Mountain Lake Airport utilizing the instrument approach regularly over the last few years, and that this was the first time he needed to divert to an alternate airport.
The pilot was receiving flight following services from Air Traffic Control for the initial en route portion of the flight. The Federal Aviation Administration (FAA) provided radar and voice communication data for the flight. The data revealed a target departing the San Carlos area displaying a 4530 beacon code. The target continued traveling on a direct northeast track at a mode C reported altitude of 5,500 feet msl. About 1845, with the target 4 miles south of Livermore, the pilot established communication with Northern California Terminal Radar Approach Control. The pilot stated that he was "level 5,500 for Pine Mountain Lake." The controller, who was monitoring the Tracey radar position, responded to the pilot, providing an altimeter setting for Stockton.
The target continued on the same track at an altitude of 5,400 feet for the next 25 minutes. The pilot then reported, "Saratoga 4175A, we still don't have Pine Mountain and Lake, but we are going to switch over." The controller responded, approving a frequency change and requesting that the pilot squawk VFR. The pilot responded, "We may come back to you if it's fogged in over at Pine Mountain." The controller then acknowledged the pilot's statement. This was the last recorded communication with the pilot prior to the accident.
At 19:10:54, 12 miles southwest of Pine Mountain Lake Airport, the 4350 code radar target disappeared, and was replaced by a target on a 1200 beacon code. Over the course of the next 3 1/2 minutes the target began a descent to 4,000 feet on a heading of about 045 degrees magnetic. As the target approached within about 4 miles of the airport, it made a right turn to about 090 degrees, in line with runway 090. The target then overflew the airport at 4,000 feet. For the next 30 seconds, the target changed heading to the northeast, maintaining altitude. The target continued on this heading for the next 20 seconds climbing to 4,500 feet. The next radar return appeared 20 seconds later, 1,000 feet lower, and 3/4 mile to the south. Over the next 60 seconds, the target began a series of oscillating altitude and heading changes with amplitudes varying between 3,500 and 4,600 feet, and 205 and 340 degrees respectively. The final radar return occurred at an altitude of 3,600 feet, 800 feet south of the accident site.
A review of FAA airman records revealed that the 70-year-old-pilot held a private pilot certificate with ratings for airplane single-engine land, and instrument airplane. The pilot held a third-class medical certificate issued in September 2008, with the limitation that he must wear corrective lenses.
An examination of the pilot's logbook indicated a total flight experience of 1,083 hours since his first training flight in July 2000, through to his last logbook entry dated January 9, 2010. He had amassed a total of 443 flight hours in the accident airplane make and model, 17 hours of which occurred in the 90 days prior to the accident. He reported 173.4 hours of simulated instrument flight time, and 37.4 hours of actual instrument time, 1.7 of which occurred within the 6 months prior to the accident. During that period, he performed two instrument approaches. He reported 31.7 hours total night flight experience, 2.4 of which took place on flights into Pine Mountain Lake. According to the logbook, the pilot had never performed an approach into Pine Mountain Lake in actual instrument conditions.
In 2007, the pilot was involved in an accident flying N4175A while attempting to land at Pine Mountain Lake. The NTSB determined the probable cause of the accident to be, "The pilot's inadequate compensation for the gusty, crosswind and downdraft wind condition, which resulted in a hard landing."
The low-wing, retractable-gear airplane, was manufactured in 2000. It was powered by a six-cylinder, Textron Lycoming turbocharged TIO-540 engine, and equipped with a Hartzell three blade, constant-speed propeller.
Maintenance records indicated that an annual inspection was completed on May 9, 2009, at a total time of 1,310 flight hours. The most recent logbook entry documented maintenance to the landing gear system, and was dated February 5, 2010 at a total airframe time of 1,395.7 flight hours. On April 16, 2008, the aircraft's altimeter and encoding systems were tested and inspected in accordance with Title 14 CFR Part 91.411. Also, the transponder systems were tested and inspected in accordance with Part 91.413, and Part 43, appendix E&F.
At the time of the annual inspection, the engine had accumulated a total time of 949 flight hours.
The airplane was equipped with navigational and flight instruments suitable for flight in instrument meteorological conditions. Additional equipment included Garmin 430W, and 530W, Wide Area Augmentation System capable - Global Positioning System (GPS)/Navigation/Communication transceivers, and a Garmin GDL-49 satellite data link transceiver. According to the manufacturer, the GDL-49 is capable of providing weather data delivery to the 430W and 530W units.
An impact and fire damaged Garmin GPSMAP696 portable GPS receiver was located within the cabin wreckage.
According to the original equipment list, the airplane was equipped with an STEC-System 55 (with HSI) autopilot. The airframe logbooks did not indicate any recent maintenance actions applicable to the navigation or autopilot systems.
The FAA reported that there was no record of a pilot preflight weather briefing, nor was there any record of the pilot accessing Direct User Access Terminal System (DUATS) records prior to the flight.
The pilot was present at his place of employment for about 7 hours on the day of the accident. Review of internet browsing history on his office computer revealed that the last access to a weather reporting website occurred on February 16, 3 days prior to the accident.
An Automated Weather Observation System (AWOS-3), located at Columbia Airport, Columbia, California (elevation 2,118 feet msl, 16 NM northwest of accident site), registered 2 minutes prior to the accident: calm winds; 1 mile visibility; overcast 300 feet; temperature 9 degrees C; dew point 8 degrees C; altimeter setting 29.83 inches of mercury.
An aviation routine weather report (METAR) was issued at Merced Castle Airport, Merced, California (elevation 191 feet msl, 34 NM southwest of accident site), 32 minutes prior to the accident. It indicated winds from 020 degrees at 3 knots; 10 miles visibility with a broken ceiling at 2,500 feet, overcast at 5,000 feet; temperature and dew point both at 13 degrees C; altimeter setting at 29.83 inches of mercury.
An AIRMET (Airmen’s Meteorological Information) SIERRA for mountain obscuration in the vicinity of the accident location, was issued at 1242 and 1833 on the day of the accident.
NEXRAD WSD-88R Level III base reflectivity data received by the Sacramento (KDAX) site, indicated returns at 1917 consistent with precipitation in the area surrounding Pine Mountain Lake Airport.
A privately operated 'webcam' located about midfield on the north side of the airport revealed images of the weather conditions on the evening of the accident. Review of an archived image captured at 1745 indicated fog and mist enveloping the runway environment. The surrounding hills, located about 3 miles from the camera, appeared partially obscured by clouds.
According to the U.S. Naval Observatory, Astronomical Applications Department, the computed sunset occurred in Sonora, California, at 1745, with civil twilight ending at 1811.
A Notice to Airman (NOTAM) was issued for Stockton Metropolitan Airport, May 28, 2009, reporting that the Terminal Area Weather Surveillance Radar, applicable to the route of flight, was out of service until further notice.
Pine Mountain Lake Airport is located within the western foothills of the Southern Sierra Nevada Mountain range, adjacent to the southwest border of the Stanislaus National Forest.
The Airport/Facility Directory, Southwest U. S., indicated that the airport is located at an elevation of 2,933 feet above ground level, with a single asphalt 09/27 runway 3,624 feet in length. The airport is equipped with a Visual Approach Slope Indicator (VASI) for runway 9, precision Approach Path Indicator (PAPI) for runway 27, and a lighted tetrahedron.
Examination of the runway lights, VASI, PAPI, and tetrahedron 2 days following the accident revealed no failed lamps, and that the runway lights illuminated when commanded on the Common Traffic Advisory Frequency (CTAF).
The airport was configured for two instrument approaches: RNAV (GPS) Runway 09 and GPS Runway 27. The airport was of an uncontrolled type, utilizing a CTAF, and was not equipped with an official weather observation station.
WRECKAGE AND IMPACT INFORMATION
The airplane came to rest in a residential area about 1,200 feet north, and 50 feet below the approach end of runway 27. The first identified point of contact was characterized by a flat, 30-foot-wide, near-vertical swath, cut mid-level through the branches of a 50-foot-tall tree. A shattered wooden fence was located at the base of the tree, 20 feet north of the swath. Fragments of both the right wing tip, and green navigation light lens material, and angularly cut wood were recovered at the base of the fence. A 25-foot-long ground indentation continued from the fence on a heading of about 035 degrees magnetic. The indentation gave way to a crater located at the base of a tree. The crater measured 18 feet long, 10 feet wide, and 4 feet deep, and was oriented on a heading of 060 degrees. Fragments of the right wing, cabin belly stringers, and a propeller blade were located within the crater. The blade exhibited leading edge nicks with the tip separated revealing a jagged and serrated fracture surface. The tree and the area immediately surrounding the crater contained fragmented sections of wing and fuselage spar and skins, the right flap, and the right aileron. The debris field continued on a 060-degree heading for an additional 120 feet to the site of the main wreckage.
The main wreckage consisted of the cabin, empennage, and engine. The majority of the cabin structure had sustained heavy fragmentation and crush damage, and was consumed by fire. The tailcone exhibited heavy crush damage and the empennage structure remained partially attached, crushed, and twisted radially around the tailcone. The remaining sections of both wings had become fragmented and were located strewn throughout the debris field.
The engine remained partially attached to the firewall, and had not sustained fire damage. The remaining two propeller blades remained attached at the hub. Both blades exhibited leading edge gouges, and tip twist.
The wreckage did not display obvious evidence of in-flight fire, and all major sections of the airplane were accounted for at the accident site. The odor of fuel was present at the site.
Examination of the area surrounding the outer perimeter of the accident site did not reveal any evidence that the airplane had made additional prior contact with trees or obstructions.
MEDICAL AND PATHOLOGICAL INFORMATION
The Tuolumne County Coroner completed an autopsy on the pilot and reported the cause of death as the result of multiple traumatic injuries.
The FAA Bioaeronautical Sciences Research Laboratory Forensic Toxicology Research Team, Oklahoma City, Oklahoma, performed toxicological testing on specimens of the pilot. The results were negative for all screened drug substances and ingested alcohol. Refer to the attached toxicology report for specific test parameters and results.
TESTS AND RESEARCH
The engine and airframe were examined initially on site, and then removed for further examination.
During examination of the engine, the top spark plugs were removed; no mechanical damage was noted, and the electrodes and posts exhibited light grey deposits and wear corresponding to normal operation when compared with the Champion Aviation Check-A-Plug AV-27 Chart. Visual inspection of the combustion chambers was accomplished through the spark plug bores utilizing a borescope; there was no evidence of foreign object damage or detonation, and all combustion surfaces exhibited light grey deposits consistent with normal operation.
The airspeed indicator sustained impact damage, and was located within the forward cabin area. The indicator needle was not located; a needle-shaped scratch and transfer mark was noted on the instrument face, in line with the 200 knots position.
Impact damage and post accident fire prevented a determination of the operational status of the flight instruments or autopilot system. Examination of the remaining wreckage revealed no evidence of pre-mishap or mechanical malfunctions of the engine and airframe.
FAA Advisory Circular 60-4A states in part, "The attitude of an aircraft is generally determined by reference to the natural horizon or other visual references with the surface. If neither horizon nor surface references exist, the attitude of an aircraft must be determined by artificial means from the flight instruments. Sight, supported by other senses, allows the pilot to maintain orientation. However, during periods of low visibility, the supporting senses sometimes conflict with what is seen. When this happens, a pilot is particularly vulnerable to disorientation. The degree of orientation may vary considerably with individual pilots. Spatial disorientation to a pilot means simply the inability to tell which way is 'up.'...Surface references and the natural horizon may at times become obscured, although visibility may be above flight rule minimums. Lack of natural horizon or such reference is common on over water flights, at night, and especially at night in extremely sparsely populated areas, or in low visibility conditions.... The disoriented pilot may place the aircraft in a dangerous attitude... Therefore, the use of flight instruments is essential to maintain proper attitude when encountering any of the elements which may result in spatial disorientation."