BISHOP, CA, USA
N2737R
Piper PA-28R-200
The pilot reported that he intended to fly a direct route from his departure point to the destination, a route that crossed the Sierra Nevada mountains of California. Recorded radar data showed the aircraft on a northwesterly heading as it approached the mountain range from the east, cruising VFR at 14,500 feet msl, and approaching 13,558-foot Mount Goddard. Forecast winds aloft were northwesterly approximately 50 knots. In the 9 minutes before the aircraft disappeared from radar, mode-C decoded altitude data showed the aircraft descended from 14,500 feet to 13,200 feet. The wreckage was located near where radar contact was lost at the 13,200-foot level on the mountain side. Two pilot reports stated that the mountain peaks were obscured in clouds. The aircraft cruised above 12,500 feet for more than 50 minutes prior to the accident. There was no supplemental breathing oxygen aboard.
HISTORY OF FLIGHT On November 6, 1998, at 1454 hours Pacific standard time, a Piper PA-28R-200, N2737R, was destroyed when it impacted mountainous terrain at 13,200 feet mean sea level (msl) during cruise flight 25 miles southwest of Bishop, California. The commercial pilot and two passengers were fatally injured. Visual meteorological conditions existed and no flight plan was filed for the personal flight, which was operated by the pilot under 14 CFR Part 91. The flight departed North Las Vegas Airport, Nevada, at 1248, and was destined for Merced, California. The missing aircraft was the subject of an alert notice and was located by search and rescue aircraft on November 12, 1998, on the east face of Mount Goddard. Prior to departure, the pilot told controllers in the North Las Vegas Air Traffic Control Tower that, after takeoff, he intended to navigate via heading 270 degrees direct to the Friant VORTAC navigation aide, 46 miles east of Merced. A direct course from North Las Vegas to Friant is approximately 267 degrees (magnetic) and passes approximately 10 miles south of the accident site. After departure, the pilot received traffic advisories while navigating under visual flight rules (VFR). Advisories were issued initially by Las Vegas Terminal Radar Approach Control (TRACON), then Los Angeles Air Route Traffic Control Center (ARTCC), and then High Desert TRACON. At 1437, High Desert TRACON handed the flight off to Oakland ARTCC. At 1440, the pilot established radio contact with Oakland ARTCC and was issued the Fresno altimeter setting. The pilot acknowledged the altimeter setting. There was no further communication with the aircraft. The Safety Board investigator listened to a recording of the final radio transmission. Although the transmission quality (radio quality) was weak and scratchy, the pilot's voice was intelligible. The Safety Board investigator reviewed recorded radar data provided by the USAF (Auxiliary) Civil Air Patrol. The data was a composite of National Track Analysis Program (NTAP) data and raw data from High Desert TRACON. In the 9 minutes before radar contact was lost at 1454, the aircraft track proceeded northwest-bound on approximately a 285-degree course (magnetic) until radar contact was lost near the accident location. In the same 9 minutes, the mode-C decoded altitude of the aircraft was initially at 14,500 feet and descended to 13,200 feet at the time radar contact was lost. Another pilot was flying northbound up the Owens Valley to Mammoth Lakes and passed over Independence about the time of the accident. He reported that he was flying over the middle of the valley and that there was a 30-knot headwind accompanied by strong up- and downdrafts of typically 1,000 feet per minute. The turbulence was sufficient that he could not maintain altitude and he had to let the aircraft fly between 10,500 and 12,500 feet. Although the Owens Valley was clear, the mountain peaks west of the valley were obscured in clouds. The report of the National Park Service (attached) states that no equipment associated with supplemental breathing oxygen was observed at the accident site. After takeoff at 1248, the pilot reported to air traffic control at 1310 that the aircraft was climbing through 9,800 feet, and that he intended to cruise at 12,500 feet initially and later would climb to 14,500 feet. At 1317, he reported climbing through 11,600 feet for 12,500 feet. At 1328, the pilot advised he was climbing to 14,500 feet. At 1402, the pilot reported that the aircraft was at 13,000 feet climbing to 14,500 feet. PERSONNEL INFORMATION According to the pilot's wife, the flight originated in Fresno, California on the morning of the accident. The party did not remain over night in Las Vegas. The pilot's wife reported that her husband was well rested before the trip, and that he exercised regularly and did not smoke tobacco products. METEOROLOGICAL INFORMATION The pilot contacted Reno Automated Flight Service Station (AFSS) at 1226, and received a full weather briefing for the flight from North Las Vegas to Fresno via Merced. The contents of the briefing were not recorded at the AFSS due to an equipment malfunction. A report of the malfunction is attached. The National Oceanic and Atmospheric Administration provided pilot reports (PIREPS), in-flight advisories (AIRMETS), and winds aloft forecasts (FD's) which were in effect at the time of the accident. The winds aloft forecast for Bishop between 1300 and 2200 on the day of the accident was for winds from 290 degrees (true) at 36 knots at 12,000 feet, and from 300 degrees at 68 knots at 18,000 feet. At 1306, the pilot of a UH-1 helicopter en route from Fresno to Las Vegas at 14,000 feet reported moderate turbulence over the mountains and that the Sierra Nevada mountains were obscured in clouds. AIRMET Zulu 3 was in effect for occasional rime and/or mixed icing in clouds and in precipitation above the freezing level to 18,000 feet msl. The forecast freezing level was 6,000 to 9,000 feet. WRECKAGE AND IMPACT INFORMATION Because of the accident location on a steep mountain rock face at 13,200 feet msl, the Safety Board did not respond to the accident scene. According to the National Park Service report of the scene (attached), the accident location was at latitude 37 degrees 6.09 minutes north and longitude 118 degrees 43.19 minutes west. The elevation was approximately 13,200 feet msl. The location is near the summit of a ridge extending southwest from the peak of (13,558 foot) Mt. Goddard. The location was described as a snow and ice filled couloir of approximately a 40-degree slope. The slope of the couloir directly below the crash site increased to approximately 60 - 70 degrees. The aircraft was resting on a northwesterly heading. The engine and propeller were located about 50 feet west-northwest of the fuselage. The left wing was bent aft toward the tail of the aircraft. The report also notes that the mixture control was at mid-range and the propeller (rpm) control was full forward. A black knob, identified in the report as the carburetor heat knob, was also all the way forward. In fact, this model aircraft does not have carburetor heat (the engine is fuel injected). The engine throttle control is a black knob, which is adjacent to the propeller and mixture controls. The park service report also noted that the compass was indicating 330 degrees and the airspeed was zero. The aircraft was recovered from Mt. Goddard on September 28, 1999. The Safety Board examined the wreckage on October 8, 1999 at the facilities of Aircraft Recovery Service in Compton, California. The fuselage was destroyed forward of the main wing spar carry-through structure (the mid-cabin station), and both wings were separated from the fuselage. The empennage was intact. The wing spar carry-through structure and remnants of the forward fuselage structure were deformed (canted) about 15 degrees to the left of the fuselage centerline. The flight control continuity was severed several places in the cockpit; however, the flight controls were continuous in the wings and empennage. Cable ends exhibited fraying except where the left wing cables were cut to facilitate recovery of the aircraft. No oxygen or GPS navigation equipment was observed. The left wing was separated from the fuselage at the wing root and was in three major pieces; the section inboard of the flap/aileron juncture with the flap attached, the outboard wing section, and the aileron. The lower surface of the outboard wing section exhibited a shredded appearance with heavy leading edge to trailing edge gouges and skin tearing across the underside. The leading edge exhibited modest impact damage and the upper surface was buckled by the lower surface damage. The inboard section of the wing was separated from the fuselage at the wing root attach fittings. The outboard end of the wing main spar was bent smoothly up and aft about 20 degrees over the outboard 3 feet where it separated from the outboard wing section. The lower wing skin forward of the spar and outboard of the fuselage had a gouge approximately 1.5 feet in diameter. The fuel tank was split open at the lower, outboard end. The landing gear was attached to the wing and was in the extended position. The right wing was separated from the fuselage along a diagonal fracture extending from the wing leading edge about 2 feet outboard of the fuselage, aft and outboard to the area of the flap/aileron juncture, through the landing gear attachment. There were two large, deep gouges in the lower wing skins aft of the leading edge and forward of the wing spar. One gouge ruptured the fuel cell and the other was approximately 4 feet inboard of the wing tip. The landing gear was separated from the wing at the trunnion attachment. The light bulb of the stall warning annunciator light was examined under a magnifying glass. The filament was intact and exhibited modest irregular spacing of the filament coils between the posts, bunched and twisted filament around one of the posts, and debris on the inner surface of the glass shell. The propeller remained attached to the engine, although the propeller shaft was broken over about 80 percent of its circumference at the attachment to the propeller flange. The propeller hub was bent downward and to the right with respect to the engine crankshaft. Each propeller blade had a gouge in the leading edge about midspan that was about 1/2-inch deep and 3 inches long and other, smaller leading edge gouges. One blade had the outboard 18 inches of the blade rolled up with 1/8-inch deep chordwise striations on the blade forward surface. The other blade was missing 6 inches of the blade tip and exhibited similar chordwise striations. The engine exhibited crushing damage on the left-hand side of the oil sump and the fuel injection servo and exhaust system were off the engine, as were the magnetos, fuel pump, and vacuum pump. The exhaust muffler was crushed flat. Borescope inspection of the cylinders revealed corrosion (rust) in the cylinders and the engine could not be rotated by hand. The pistons, valves, and cylinders were visually undamaged. The accessory case gearing, viewed through the magneto mounting pads, was visually undamaged. Both magnetos were placed on a test stand and sparked at all four posts. The spark plug electrodes were covered with an orange-colored deposit resembling iron rust and the center electrodes were oval. The spark plug harness was separated at several locations but was intact at the spark plug and magneto attachments. The fuel injector nozzles were clear and the diaphragm in the flow divider was intact. The plunger in the flow divider was corroded in the bore. The fuel pump was opened and the diaphragms and check valves were intact. The vacuum pump shear coupling was intact, as were the internal rotor and vanes. The fuel servo inlet screen and oil filter were free of any foreign matter. MEDICAL AND PATHOLOGICAL INFORMATION The Fresno County Coroner performed an autopsy on the pilot, case number 98-11-022. The FAA's Civil Aeromedical Institute in Oklahoma City, Oklahoma, performed toxicological tests. The tests were negative for carbon monoxide, alcohol, and drugs. ADDITIONAL INFORMATION The aircraft wreckage was released to Mr. Jerry Wallace, insurance adjuster for Great American Insurance Company on October 8, 1999.
The failure of the pilot-in-command, after encountering a downdraft, to maneuver and maintain clearance from mountainous terrain. Physical impairment due to hypoxia was a factor in the accident.
Source: NTSB Aviation Accident Database
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