Aviation Accident Summaries

Aviation Accident Summary LAX95FA157

POLLACK PINES, CA, USA

Aircraft #1

N3904T

PIPER PA-28R-180

Analysis

THERE WAS NO RECORD THAT THE PILOT RECEIVED A PREFLIGHT WEATHER BRIEFING FROM THE FAA OR NWS SYSTEMS. THE PILOT TOLD THE OPERATOR HE CHANGED HIS DESTINATION DUE TO HIGH WINDS TO AN AREA WITH BETTER WEATHER. THE PILOT CHANGED HIS DESTINATION A SECOND TIME WITHOUT TELLING THE OPERATOR TO AN AIRPORT THAT WOULD REQUIRE CROSSING THE SIERRA NEVADA MOUNTAINS. HIGH WINDS WERE ALSO FORECASTED FOR THE MOUNTAINS. A CENTER WEATHER WATCH WAS BROADCASTED BY APPROACH CONTROL, WHILE THE PILOT WAS ON THE FREQUENCY, FORECASTING MODERATE AND OCCASIONAL SEVERE TURBULENCE, STRONG UP-AND-DOWN DRAFTS, LOW LEVEL WIND SHEAR, AND WIND GUSTS UP TO 45 KNOTS. THE CLOSEST WEATHER OBSERVATION STATION WAS UPWIND OF THE ACCIDENT SITE. THE STATION HAD TAKEN SIX SPECIAL WEATHER OBSERVATIONS IN ADDITION TO TWO SCHEDULED OBSERVATIONS DUE TO CHANGING WEATHER CONDITIONS. THE AIRPLANE WAS OBSERVED DESCENDING UNCONTROLLED WITHOUT THE TAIL BY NUMEROUS WITNESSES. ICE WAS OBSERVED ON THE WINGS, IN AN INDUCTION HOSE, AND THE RAM AIR PORT OF THE PITOT STATIC SYSTEM AFTER THE ACCIDENT.

Factual Information

History of the Flight On April 8, 1995, at 1412 hours Pacific daylight time, a Piper PA-28R-180, N3904T, separated in flight and descended uncontrolled and collided with terrain in Pollock Pines, California. The airplane was destroyed and the certificated private pilot and three passengers received fatal injuries. The airplane was being operated by S & S Flight Center, Bakersfield, California. The pilot rented the airplane from the operator to conduct a personal flight. The flight departed Bakersfield about 1205 hours, and was destined for South Lake Tahoe, California. The pilot had scheduled the accident airplane for an overnight trip to Las Vegas, Nevada, beginning at 1200 hours on April 8, 1995, to 1800 hours on April 9, 1995. The airplane operator had called the pilot approximately 1000 hours to confirm the airplane reservation because the en route weather to Las Vegas was not suitable due to high winds. The pilot told the airplane operator that he changed his destination to Sacramento because the weather was clear. The pilot and passengers arrived at the Bakersfield Municipal Airport about 1140 hours. At the time, the accident airplane was being flown by a flight instructor administering dual instruction to another pilot. The airplane operator contacted the flight instructor on radio and informed him the airplane needed to be back by 1200 hours. At 1145 hours, the pilot met the flight instructor on the ramp with his passengers and their baggage. The flight instructor spoke to the pilot. The flight instructor told the pilot the airplane was in good condition and everything was operational. The pilot told the flight instructor his destination was Lake Tahoe. The flight instructor recommended to the pilot the he not fly in instrument or poor weather conditions. The pilot told the flight instructor the weather was good "VFR" (visual flight rules). There was no record found during the investigation of the pilot receiving an aviation weather briefing. The operator maintains a computer in the flight planning area for pilots to obtain weather information and file flight plans. According to the operator, the pilot did not use their flight planning area on the day of the accident. At 1208 hours, the pilot contacted the Bakersfield Approach Control and informed the sector controller that he had departed Bakersfield Municipal Airport, climbing to 5,500 feet above mean sea level (msl) in VFR conditions. The pilot also requested radar traffic advisories and informed the sector controller his destination was Lake Tahoe. The sector controller then radar identified the airplane climbing through 4,500 feet, issued an altimeter setting, and provided routine VFR flight following. At 1212 hours, the sector controller broadcasted a "Center Weather Advisory" pertinent to the accident airplane's route of flight to Lake Tahoe. The Center Weather Advisory issued warnings of moderate and occasional severe turbulence, possible strong up-and-down drafts, low level wind shear, mainly near the mountains, and moderate-to-severe wind gusts, possibly up to 45 knots. At 1232 hours, the Bakersfield Approach terminated radar service with the pilot and advised the pilot of the Fresno Approach Control frequency for further VFR flight following. At 1935 hours, the pilot called Fresno Approach Control for radar traffic advisories and was radar identified 15 miles southeast of Visalia, California. At 1300 hours, the pilot reported climbing from 8,500 feet msl to 10,500 feet msl. The Fresno Approach sector controller terminated radar services and advised the pilot he could contact Oakland Center for further radar advisories. There was no record found of the pilot contacting Oakland Center. Review of Oakland Center radar data, NTAP (National Track Analysis Program) disclosed a VFR beacon code (1200) disappeared from radar over the accident site at 1412 hours. There were 36 other radar hits in the vicinity of the accident site in the NTAP data over a 7-minute period. The NTAP data was graphically plotted in time sequence. The first data point was at 1405:03 hours at a position 9.04 nautical miles east-southeast of the accident site at an altitude of 11,200 feet msl. A scaled overlay of the NTAP data revealed, as time progressed, subsequent radar hits that moved closer to the accident site. There were 14 radar hits in time sequence that contoured the north shore of Jenkinson Lake in a descent from an altitude of 10,700 feet msl to 10,400 feet msl. The third from the last radar hit indicated an altitude of 9,400 feet msl. The last radar hit was 24 seconds later at 4,300 feet. There was no altitude data displayed for the second to last radar hit record 12 seconds before the last. Numerous witnesses stated their attention was drawn to the airplane by the sound of its engine. Several of the witnesses reported hearing a loud "bang" noise. They then looked up and saw the airplane descending uncontrolled without its tail. Other witnesses saw falling debris. Many of the witnesses then reported the accident to the El Dorado County Sheriff's Department. The witnesses stated that it was snowing at the time of the accident. Several sheriff's deputies and one homeowner reported an accumulation of ice ranging from 1/4- to 1/2-inch thick on a separated wing, and a wing still attached to the airplane. Pilot Information The pilot held a private pilot certificate which was issued on June 6, 1974, with a single engine airplane rating. The pilot did not possess an airplane instrument rating. The most recent third-class medical certificate was issued to the pilot on May 26, 1993, and contained the limitation that correcting lenses must be worn while exercising the privileges of his airman certificate. No personal flight records were located for the pilot, and the aeronautical experience listed in this report was obtained from the operator's accident report and the experience gained during the accident flight. Aircraft Information A standard airworthiness certificate was issued for the airplane after it was manufactured on November 11, 1967. The airplane had accumulated a total time in service of 2,291 hours. According to the airframe manufacturer, the airplane is not certified for flight into icing conditions. Meteorological Information The closest official weather observation station is McClellan Air Force Base, which is located 38.4 nautical miles west of the accident site. The elevation of the weather observation station is 75 feet msl. The weather facility normally takes hourly scheduled weather observations and special weather observations when weather changes significantly. From 1255 hours to 1355 hours, weather observers at McClellan AFB took six unscheduled special weather observations, in addition to the two scheduled observations. At 1428 hours, an unscheduled special surface observation was reporting in part: sky condition and ceiling, 3,000 foot scattered, measured 5,000 foot broken, 7,000 feet overcast; visibility, 8 miles light rain; winds 210 degrees at 7 knots. Wreckage and Impact Information The fuselage came to rest at 38 degrees 45.20 minutes north latitude and 120 degrees 34.58 minutes west longitude. The accident site is located in a residential area of Pollack Pines, California. The average elevation in the area is 3,500 feet msl. The residential area is mountainous and covered by numerous mature trees with 2-foot diameter trunks, and some as high as 150 feet above the ground. The site is about 3,500 feet south of State Highway 50. The highway follows the American River Valley, and according to residents of Pollock Pines, is used frequently by pilots to navigate from Sacramento to South Lake Tahoe. The airplane's fuselage with porions of both wings came to rest on sloping terrain behind a residence located at 6434 Topaz Drive. The airplane contacted trees before hitting the ground. The airplane, along with broken branches from the trees, struck the roof of the residence, damaging it. The airplane came to rest inverted with the broken stub of the right wing and propeller embedded in the ground, and the left wing touching the ground. The airplane's cabin roof was crushed and collapsed to the base of the windshield at the instrument panel and the bottom of the cabin windows. The propeller was found attached to the engine. One propeller blade was embedded in the ground. Both propeller blades were bent forward slightly at midspan and curled aft at the tips. A 4-foot section of the left wing tip was broken and found behind the Topaz Drive residence near the fuselage. The aileron and counter weight remained attached to the wing tip. The aileron was found bent along its longitudinal axis in a horseshoe shape, corresponding to the wing tip separating in a downward direction. An 8-foot section of the right wing was found about 3,000 feet north of the fuselage in front of a residence located at 3210 Sly Park Road. The right aileron with the counterweight was found about 100 feet west of the house at the same address. The right wing was bent downward at the broken end. The aft portion of the empennage was separated from the fuselage and was found scattered in pieces in a green belt area between the location of the right wing tip and the fuselage. The green belt area is bounded by Amber Trail on the north and Topaz Drive on the south. The airplane's rudder was torn into three pieces. One 28-inch- long piece was found on the front porch of a residence at 3224 Amber Trail. The vertical stabilizer with the upper piece of the rudder attached by a hinge was found suspended about 12 feet in the air in a tree above a stream behind the residence. About 150 feet east of the vertical stabilizer, the horizontal stabilator with counter balance weight, the aft tail cone, the lower portion of the rudder, and associated control cables were found suspended in a tree 108 feet above the ground. The left leading edge of the stabilator was torn away and was also found suspended in a tree about 100 feet above the ground about 300 feet east of the vertical stabilizer. Examination of the stabilator revealed the right and left segments were curled upward at the tip and twisted backwards. The pitot static system mast was found the day after the accident separated from the wing under a deck that protected it from the elements. Ice was found in the ram air inlet. The pitot heat switch was examined and was found in the off position. Ice was also found in flexible hose of the airplane's induction system the day after the accident while removing the engine from the airframe. Medical and Pathological Information A post mortem examination on the pilot was conducted by the El Dorado County Coroner's Office on April 9, 1995, with specimens retained for toxicological examination. The toxicological tests were performed by the Federal Aviation Administration's Civil Aeromedical Institute (CAMI) located in Oklahoma City, Oklahoma. The results of the toxicological analysis revealed the presence of Pseudoephedrine and Ephedrine in the blood and liver fluid. According to CAMI, the substances are found in over-the-counter medications and are permitted to be used while piloting an aircraft. CAMI did not quantify permissible over-the-counter medication during their toxicological analysis. Tests and Research Wreckage Reconstruction The airplane was recovered from the accident site and reconstructed. Control cables were present from the instrument panel and wing flight control surface bell cranks to the area of the fuselage center section. Control cables from the empennage remained attached to the control surfaces and were broken at the fuselage center section. All control cable pulleys, except one which was missing, were examined. There was no unusual operating signatures noted on the control cables, pulleys, or control surface limit stops. The missing pulleys sheet metal mounting structure was torn. There was no evidence of unusual wear pattern found on the pulleys sheet metal mounting structure. Engine Examination The engine was examined at the accident scene on April 9, 1995, and at the aircraft recovery company's facilities on April 10, 1995. All spark plugs displayed normal operating signatures, and the left magneto sparked in firing sequence with engine rotation. Small flakes of carbon were found adhering to the perforated structure of the oil sump screen. There was no evidence of metallic particles on the screen, or observed in the engine oil. Further examination did not reveal any evidence of mechanical failure or malfunction with the engine. Additional Information Wreckage Release The wreckage was released to the owner's representatives on April 10, 1995.

Probable Cause and Findings

The pilot's disregard of a hazardous weather advisory; his decision to fly into known adverse weather conditions; his failure to maintain control of the airplane with an accumulation of airframe ice; and his improper use of the flight controls during recovery from the inflight upset exceeding the airplane's stress limits. The adverse weather and airframe ice were factors in the accident.

 

Source: NTSB Aviation Accident Database

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