LAX96FA119
LAX96FA119

HISTORY OF FLIGHT

On February 19, 1996, at 1315 hours Pacific standard time, a Beech C35, N2PA, collided with mountainous terrain in the Sierra Nevada Mountains near Lee Vining, California, following a loss of engine power. The aircraft was owned and operated by the pilot and was on a personal cross-country flight from Las Vegas, Nevada, to Oakland, California. Instrument meteorological conditions prevailed in the area of the accident site. The pilot filed and received an IFR clearance while in flight. The aircraft was destroyed in the collision sequence and the private pilot, the sole occupant, sustained fatal injuries.

During the investigation, recorded radar data and all known voice air-to-ground communications were obtained from the involved Federal Aviation Administration (FAA) facilities for detailed review. The radar data was provided in two formats consisting of the National Track Analysis Program (NTAP) and Data Analysis Reduction Tool (DART). The DART data was requested in both a Log Sort and Track Sort version. All recorded air-ground communications between the aircraft and the ground stations were examined in both a written transcript version, and by listening to the certified re-recordings of the actual tapes. Information discussed in the pertinent portions of this narrative report were derived from the above sources. The radar data and communications transcripts are appended to this report. The re-recordings of the communications tapes are included in the docket for this accident.

Initial information provided to the Safety Board led investigators to believe that the flight originated in Tonopah, Nevada, on the morning of the accident. Subsequent inquiries disclosed that the flight in fact originated from McCarran International Airport, Las Vegas, Nevada, on the morning of the accident. At the time this information was revealed, 14 days had elapsed and the FAA air-ground communications recording mediums at McCarran had been recycled so the flight's exact departure time was not available. The estimated departure time of 1050 PST was reconstructed based on a review of records obtained from the Fixed Base Operator (FBO) where the aircraft was parked while at McCarran, and time elements based on aircraft performance data, times of ATC contact over the Coaldale VOR, the known upper air winds, and ground speeds obtained from the recorded radar data.

Records obtained from Eagle Flight Services, Inc., at McCarran International Airport disclosed that the aircraft arrived on February 16 and departed on February 19, 1997. The sales ticket for payment of services provided was date and time stamped on February 19 at 1030.

Review of National Weather Service and FAA Flight Service Station (FSS) facility records disclosed no evidence of a preflight weather briefing under either the aircraft registration number or the pilot's name.

At 1204 the pilot contacted the FAA Reno FSS by radio, stated the flight's position as over the Coaldale VOR, and requested only the current Oakland weather. The briefing specialists provided the current and forecast weather, in addition to the area forecast and flight advisories in effect for the route of flight between Coaldale and Oakland. During the exchange, the specialists reported that airmets were in effect for mountain obscuration, moderate turbulence, and moderate mixed icing conditions from the 10,000 foot freezing level to 20,000 feet. The pilot responded that he had been "at 10,000 to 12,000 feet since leaving Las Vegas" and had experienced only light chop.

Ten minutes later the pilot contacted Reno FSS again by radio and air-filed an IFR flight plan to Oakland from Coaldale VOR via Victor (airway) 244 direct Oakland. Thirteen thousand feet was requested as the cruising altitude and the pilot reported 4 hours of fuel onboard.

The pilot's first radio contact with Oakland Air Route Traffic Control Center (ARTCC) was at 1217 when he reported his position as "13 DME south of the Coaldale VOR" and requested to pick up his IFR clearance to Oakland. The sector controller identified the aircraft's radar position as 5 miles southwest of the VOR and inquired what altitude the pilot requested as his final cruise altitude. The pilot responded with "one thousand four thousand." The controller then issued the pilot an altitude assignment to maintain 16,000 feet. At the same time, the controller also amended the pilot's route to present position direct Panoche VOR, Victor (airway) 301 to Sunol intersection, thence direct to Oakland. According to an aeronautical chart, the course line of that routing to Panoche is 25 degrees left of the 250 degree outbound radial of the Coaldale VOR, which defines Victor 244. The pilot responded that he was having difficulty finding Panoche and asked the controller "can you give me a hand." The controller provided the pilot with a 225-degree heading assignment and instructed him to "proceed direct Panoche when able."

Ten minutes later at 1235, the pilot made the first of many subsequent requests for a clearance to a lower altitude. The controller responded that 16,000 feet was the lowest Minimum Vectoring Altitude (MVA), and added that it would be 60 miles before the pilot could get a lower altitude.

Review of the recorded radar data disclosed that during the time frame from 1224 to about 1306, the aircraft's ground track averaged 238 degrees magnetic, which is roughly half the difference between the outbound 250 radial from Coaldale and the 225-degree heading assigned by the controller. According to the DART radar data, the aircraft's ground speed computed by the FAA air traffic system computer was averaging 85 knots. The aircraft's mode C reported altitude was noted as generally 16,000 feet, with occasional 100-foot excursions above and below that altitude until 1301. Between that time and 1312, the mode C reported altitude began a descent to values as low as 15,300 feet.

At 1301, the controller queried the pilot about his altitude and the pilot reported that he was having difficulty holding altitude due to turbulence. In response, the controller cleared the flight to maintain a block altitude between 15,000 and 16,000 feet and noted the flight's radar position as 60 miles west of Coaldale. The pilot then asked again for a lower altitude, to which the controller responded that 15,000 feet was the lowest possible MVA for the next 25 miles. After coordinating with nearby sectors, the controller amended the pilot's clearance at 1306 to present position direct Manteca VOR (along Victor 244, the pilot's original route request) Victor 195 Sunol intersection.

The pilot declared an emergency at 1312:33, reported that the "engine was out," and requested services. The controller responded 4 seconds later that the closest airport was Bridgeport at the pilot's 3 o'clock position at 21 miles. Thirty-seven seconds later the controller advised the pilot that the Lee Vining airport was at his 6 o'clock position 9 miles away and provided a suggested heading of 040 for the airport. The last radio transmission from the aircraft was at 1314:55, and the last transponder return was at 1314:44 at a mode C reported altitude of 13,800, about 4.8 statute miles southwest of the impact site.

The accident site is in rugged mountainous terrain near the top of the 11,697-foot-tall Lee Vining peak at longitude 119 degrees 18.9 minutes west by latitude 37 degrees 50.4 minutes north.

AIRCRAFT INFORMATION

Partial maintenance records limited to the most recent logbooks for the airframe and engine were recovered and examined. No historical modification or alteration records were available. A 1952 production model Beech C35, the aircraft had accumulated a total time in service of 5,556 hours. The most recent annual inspection was completed on October 18, 1995, 45 hours prior to the accident.

Beech production records disclosed that the aircraft was originally delivered without an oxygen system or wing tip fuel tanks. The optional factory fuel system installed on the production line consisted of a 20-gallon main tank in each wing and a 20-gallon auxiliary tank mounted in the fuselage behind the rear cabin baggage area. Each wing tank has a 17-gallon useable capacity, while the auxiliary fuel tank in the fuselage contains 19 useable gallons. The original factory installed engine was a Continental E-185-11.

According to Beech Aircraft, the power plant installation for either the E-185 or E-225 series Continental engines does not provide for an alternate air source for the induction system other than through the carburetor heat system, which is available by activation of a cockpit control lever.

Examination of the wreckage disclosed that a normally aspirated Continental E-225-8 engine was installed in the airframe. Wing tip fuel tanks, which appeared to be of the 15-gallon capacity size, and, a fixed oxygen system were also found installed.

Review of the maintenance records disclosed that the engine was installed in the airframe on April 10, 1972, and had accumulated a total time in service of 2,853 hours, with 1,080 hours since the last major overhaul. At the last annual inspection on October 18, 1995, cylinders 2, 5, and 6 were replaced, and new magnetos were installed. In addition, the entry noted that weld repairs were made to the exhaust tubing.

As noted in the History of Flight section of this narrative, the aircraft was parked while at Las Vegas at Eagle Flight Services, Inc. Records from the FBO disclosed that the aircraft was refueled on February 16th after arrival with the addition of 24.1 gallons of 100 low lead aviation fuel. The records did not disclose into which tanks the fuel was added, and line personnel could not recall any details of the fueling. The fuel quantity distribution in the tanks at arrival in Las Vegas are unknown. Based upon the pilot's statement of "4 hours fuel on board" at the time he filed his flight plan and the known engine fuel consumption for the Continental E-225-8 engine, Beech Aircraft Company engineering personnel opined that the main and auxiliary were filled to capacity at departure.

Eagle Flight Service company records disclosed no evidence that the oxygen system was serviced while the aircraft was parked at their facility.

The pilot's father was interviewed by telephone on June 4, 1996. He reported that he is a general aviation pilot and has flown in the accident aircraft with his son for about 200 hours. On February 15th he spoke to his son and the pilot told him that the aircraft "was flying fine" and there were no known complaints or problems.

PILOT INFORMATION

Review of FAA airman and medical records disclosed that the pilot held a private pilot certificate with ratings for airplanes single engine land and instruments. His instrument rating was issued on March 26, 1994. The last medical certificate of record was a second class, which was issued on November 5, 1993, with the limitation that corrective lenses must be worn.

The pilot's logbook was examined and the review disclosed that he began flying in October 1991, and obtained the original issuance of his private pilot certificate in February 1992. In that month he first began flying the accident aircraft. Accumulating a total time of 603 hours, the pilot had flown about 530 of that in the Beech C35. In the preceding 90 and 30 days prior to the accident, the pilot had respectively flown a total of 28 and 6 hours, with 9 and 3 of those in actual or simulated instrument conditions.

In an interview, the pilot's father reported that his son was a federal law enforcement officer, in good health, and a non-smoker. The pilot initially learned to fly in the southeast United States, then continued flying after he moved to Tucson, Arizona, in the desert areas of the southwest. The pilot had only recently moved to Oakland within the last couple of months, and the father believed that his son did not have much experience flying over the Sierra Nevada Mountains.

COMMUNICATIONS

Detailed review of the air-ground communications tape re-recordings disclosed that the pilot successfully communicated with Reno FSS and several Oakland ARTCC sectors, with no transmission or reception difficulties noted.

AIDS TO NAVIGATION

Examination of FAA facility records disclosed that all ground-based navigation aids pertinent to the aircraft's route of flight after the Coaldale VOR were operational on the day of the accident. Detailed review of the air-ground communications tape re-recordings disclosed no transmissions from other aircraft in the vicinity which noted ground equipment outages or problems.

METEOROLOGICAL INFORMATION

As noted in the History of Flight section of this narrative, no evidence was found that the pilot obtained a preflight weather briefing. While in flight near the Coaldale VOR at 1204, the pilot contacted Reno Flight Service Station and requested only the current Oakland weather. The briefing specialists provided the pilot with the current and forecast Oakland weather, and in addition, the current AIRMETS in effect for the pilot's intended route.

A meteorological study was performed by a Safety Board staff meteorologist and that report is appended to this one. In pertinent part, the meteorologists factual report notes that cloud tops in the vicinity were in the 22,000- to 24,000-foot range. Cloud bases for reporting stations north and south of the accident site were less than 1,000 feet agl during the accident time frame. For two stations, one north and the other south of the accident site, the winds aloft at 16,000 feet msl were from the west and southwest at 68 and 66 knots, respectively.

The Area Forecast, AIRMETS and SIGMETS issued and available prior to the pilot's departure from Las Vegas were reviewed. The area forecast noted cloud bases and tops of 6,000 and 25,000 feet, respectively, for the central Sierra Nevada Mountains. AIRMETS valid for the flight's route and time frame predicted mountain obscuration, moderate mixed icing conditions, and moderate to severe turbulence. The icing was anticipated in clouds from the 7,000-foot freezing level to 22,000 feet. The turbulence was expected between 8,000 and 26,000 feet.

Pilot reports of icing and turbulence were noted during a review of the communications tape re-recordings previously identified in this narrative report. One report of a severe turbulence encounter was noted from an air carrier MD-80 descending into Reno, Nevada, from the south.

WRECKAGE AND IMPACT INFORMATION

On the east face of the 11,697-foot-tall Lee Vining Peak, the accident site is at a GPS measured elevation of 10,900 feet msl at longitude 119 degrees 18.9 minutes west by latitude 37 degrees 50.4 minutes north. The site is characterized as principally a rocky 25-degree slope with sparse low scrub vegetation in the vicinity of the wreckage. Heavy snow with depths up to 10 feet was present at the time of the accident. The wreckage was documented and examined on July 25, 1996, when the snow had melted and access to the site could be gained. A GPS determined bearing and distance to the Lee Vining airport was 087 degrees at 4.16 nautical miles.

The aircraft empennage aft of the baggage area was inverted. The left wing and wing center section fuselage carry-through was right side up with the nose oriented on a southerly magnetic bearing and the left wing pointed downslope. The engine and remains of the nose section was oriented upslope in a westerly direction and remained connected to the cabin area by control and electrical cables. An area of engine compartment debris was observed on about a 340-degree magnetic bearing from the fuselage (behind and upslope) at a distance estimated at 80 feet. The segmented remains of the right wing was found 300 or more feet downslope of the main wreckage in a bowl shaped depression. All aircraft extremities were found within the described wreckage distribution area.

The Mono County Sheriff's Search and Rescue Unit located the wreckage and extricated the pilot in the days immediately following the accident. All members of the unit who participated in the recovery effort were interviewed to determine their observations relative to oxygen equipment on or near the pilot. Recovery of the pilot took place in heavy snow conditions. Snow was packed into the remains of the cabin area and the pilot was partially buried in snow. No SRU member observed an oxygen mask or tube/hose on or near the pilot. An oxygen hose was observed in a plastic bag near the rear of the cabin.

Following initial documentation, the wreckage was recovered by helicopter to a flat staging area about 2,000 feet below the site for detailed examination.

Detailed examination of the cabin area disclosed that a cannula type oxygen tube was tangled in the cord for the ICS switch. The connector fitting was not damaged. No tubes were found plugged into the cabin side wall regulator panel. The regulator valve was frozen in the off position and could not be moved. The oxygen supply tank was located in the empennage, with the main supply valve in the off position. When the valve was opened, gas flowed freely from the tank. No determination was made regarding the gas quantity or composition.

The fuel selector panel was examined in detail. Two selector valves were found mounted on the left side cockpit floor. The first valve handle was observed to be a combination selector valve and hand operated emergency "wobble pump." The handle was found with the pump function in the off and locked position. The first handle had four marked detent/positions: clockwise starting at 12 they read OFF, RIGHT MAIN 17, AUXILARY, and LEFT MAIN 17. The valve handle was found securely in the LEFT MAIN detent. The second valve handle also had four marked detent positions: clockwise starting at 12 they read, BOTH TIPS, RIGHT TIP 15, FUS AUX 20, LEFT TIP 15. This valve handle was found positioned securely in the RIGHT TIP detent. Disassembly of the valves revealed that the screens were clean, and that the valves were indexed correctly to the handle positions.

Both wing tip tanks were destroyed. Hydraulic fuel cell bladder rupture and deformation to the surrounding fuel cell containment structures was noted to the right main and fuselage auxiliary tanks. The left wing in the vicinity of the fuel cell was opened to reveal the left tank bladder. The bladder was intact with no evidence of hydraulic activity.

The landing gear and flap actuators were found in their respective up positions. Establishment of complete control system continuity was precluded by the extent of the disruption to the right wing and the cockpit area. No unusual operating signature or condition was observed on any control limit stop. The control cables were routed in the normal fashion from the cabin to the tail surface actuators, and, in the left wing.

Due to impact damage, the position of the carburetor heat control and the butterfly valve in the carburetor heat box could not be determined.

TESTS AND RESEARCH

The engine was removed from the airframe and transported to an engine overhaul facility for detailed disassembly and examination. The examination occurred on August 2, 1996, at the facilities of Lynn's Aircraft Engines, El Monte, California. A complete report of the examination is appended to this report.

Overall visual inspection revealed impact damage to the right side cylinders, with the heads of numbers 3 and 5 broken off. Impact damage was also noted to the carburetor, and numerous cracks were present on both sides of the crankcase halves. Ductile crushing was observed to the exhaust tubes, with no blow-by stains on the recent weld joints.

During removal of the wet type vacuum pump, the drive coupling was found to be intact. Hand rotation of the pump shaft produced suction.

Disassembly of the Bendix PS 5C carburetor revealed that all diaphragms and springs were intact. The fuel inlet screen was clean and a 6-tube fuel nozzle was present. The fuel pump would not rotate, and disassembly revealed the internal presence of water, with the rotor vanes rusted to the rotor housing wall.

The magneto to engine timing could not be determined. Both Bendix S6LN-21 magnetos produced strong sparks in firing order with hand rotation. All of the Champion RHM-40E spark plugs were unremarkable upon visual inspection.

A detailed internal examination of the engine was conducted following complete disassembly. Beyond fretting signatures on the bearing inserts in the crankcase saddles, all other internal components were unremarkable.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was conducted by the Mono County Sheriff-Coroner's Office, with tissue and fluid samples retained for toxicological analysis. The analysis results were negative for alcohol and all screened drug substances.

Review of the flight timing elements discussed previously in this report reveals that the pilot operated at msl altitudes above 12,000 feet in excess of 1 hour 50 minutes, with about 1 hour of that time spent between 15,000 and 16,000 feet. Detailed examination of the wreckage disclosed no evidence of oxygen availability or used by the pilot during the flight.

The AIRMAN'S INFORMATION MANUAL (AIM) is published by the FAA and contains information pertinent to many aspects of flight, including medical factors affecting pilot performance. Section 8-1-2 of the AIM discusses the physiological effects of altitude, and states in part: "Hypoxia is a state of oxygen deficiency in the body sufficient to impair functions of the brain...From 12,000 to 15,000 feet of altitude, judgment, memory, alertness, coordination and ability to make calculations are impaired...pilot performance can seriously deteriorate within 15 minutes at 15,000 feet."

The certified re-recordings of the air-ground communications tapes were reviewed several times. Several instances were noted where the pilot would respond to an altitude query by the controller by completely misstating the altitude. One example occurs in the 1217 exchange between Oakland ARTCC when the pilot refers to 14,000 feet as "one thousand four thousand." The tapes are available as part of the public docket for this accident.

ADDITIONAL INFORMATION

The Safety Board did not assume custody of the wreckage until it was accessible on July 25, 1996. The wreckage was verbally released to the pilot's father on August 3, 1996, at the conclusion of the component examinations. A signed NTSB Release of Wreckage, Form 6120.15, was mailed to the father for receipt signature but was not returned. When last viewed, the wreckage was at the facilities of HLM Air Services, Santa Paula, California.

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