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On November 27, 1994, about 1115 Pacific standard time, a Maule M-5-235C, N5629J, collided with trees at the 8,300 foot level in mountainous terrain on the south face of Kern Peak near Springville, California. The aircraft was owned and operated by the pilot and was on a personal sightseeing flight in the Sierra Nevada Mountains. Based on witness and National Weather Service observations along the route of flight, visual meteorological conditions prevailed with generally clear skies and light wind conditions. The aircraft was destroyed in the obstacle and ground collision sequence. The certificated private pilot/owner sustained serious injuries. A pilot-rated passenger and another passenger onboard sustained fatal injuries. The flight originated at Long Beach, California, on the day of the accident at 0650 and is documented to have made en route stops at the California City and Kernville, California, airports.
Several friends and associates of the aircraft owner and the pilot-rated passenger reported that on November 19, 1994, the two flew the aircraft from Long Beach into the Owens Valley area for a day-long sightseeing flight as far north as Mammoth. Videotapes were taken of portions of the flight by the pilot-rated passenger. The videotape was recovered from the wreckage and reviewed by National Transportation Safety Board investigators. The tape showed the aircraft flying low in and out of mountain valleys, and along the desert floor near Mono Lake. These same friends and associates reported that both individuals stated they intended to return to the general area on November 27th for another flight. The third occupant was reported to be an amateur photographer who enjoys shooting plants, wildlife, and outdoor scenery.
Records of Federal Aviation Administration (FAA) preflight weather briefings at the Hawthorne Automated Flight Service Station (AFSS) were reviewed. The records disclosed that at 0536 Pacific standard time on November 27th, an individual who identified himself as the pilot of N5629J telephoned and requested the current and forecast weather conditions in the Mammoth area. The individual reportedly told the briefer that the flight would proceed up the Owens Valley "as far north as Mammoth." The briefer did not have current reports for Mammoth and supplied the individual with the current weather conditions in the Reno and South Lake Tahoe area.
Air-to-ground communications tapes at the Long Beach Air Traffic Control Tower (ATCT) revealed that the aircraft was given a takeoff clearance at 0650. Subsequent radio exchanges indicated that the flight proceeded in a westerly direction toward the VFR corridor over the Los Angeles International Airport. No other documented radio exchanges have been located between the aircraft and any other FAA facility on that day.
Records of credit card purchases revealed that a credit card belonging to the pilot-rated passenger was used at the California City airport to purchase fuel from a credit card activated automatic fuel pump. The purchase was time-stamped at 0924 on November 27th and 51.97 gallons of 100 LL aviation fuel were dispensed.
All other civil airports between Palmdale and Mammoth were surveyed either in person by Civil Air Patrol search crews or by telephone.
Nelson Aviation, the fixed base operator (FBO) at the Kernville airport, Kern Valley, California, reported that their records of UNICOM contacts showed the aircraft landed at 1008, then departed again about 1030. The operator on duty stated that the aircraft landed and taxied down to the picnic area at the far end of the airport. Fueling records at the airport disclosed no evidence that the aircraft was fueled or provided with any other services.
The previously noted videotape removed from the wreckage clearly showed portions of the accident flight. The first parts of the flight showed the aircraft low flying along the desert floor in the Palmdale, California, area. The aircraft was also observed to land at several dry lake beds, and at one airport tentatively identified as California City. The tape then depicted the aircraft low flying in an area identified by a voice on the tape as Jawbone Canyon, then buzzing Lake Isabella by the Kernville airport. The aircraft was observed to land at the airport, taxi down to the picnic area, and the three occupants having something to eat. The remainder of the tape showed the aircraft flying up the Kern River Valley until it abruptly stops at a damaged portion of the tape.
On December 9, 1994, the pilot of the aircraft entered a cafe in the town of Olancha in the Owen's Valley. After having something to eat and phoning relatives, the pilot contacted the Inyo County Sheriff's Department, reported that he was involved in an aircraft accident in the mountains and that his two passengers were still at the aircraft. A sheriff's deputy and a pilot took the accident pilot in a similar aircraft and attempted to find the accident site by retracing the route the pilot said he walked along to reach the cafe. This attempt was unsuccessful. The pilot was next flown down to the area of the Kernville airport and he was able to orient himself and re-trace the accident flight up the Kern River Valley to the crash site. A U.S. Navy helicopter from the Naval Weapons Test Center at Inyokern responded to the site and found both passengers dead.
The pilot was interviewed on July, 11, 1995, at the Safety Board's Southwest Regional Office. A complete summary of the interview is attached to this report.
The pilot narrated an account of the flight starting with the departure from Long Beach. The flight proceeded to the Rosamond Skypark airport where a full stop normal landing was made. After departure from Rosamond, the flight flew to a dry lake bed, where the pilot said he normally always lands when in the area, and an additional full stop landing was made. While on the dry lake bed, the trio walked around and took some pictures of themselves and the airplane. California City was the next stop made on the itinerary, where fuel was purchased. The pilot stated that he believed 51 gallons of fuel were bought, which brought the level in the tanks to the filler necks.
After departure from California City, the flight flew directly to Kern Valley, where a full stop landing was made. The aircraft was parked at a picnic area on the airport and the three occupants had some refreshments which were brought along on the trip.
The pilot estimated that they departed Kern Valley about 1045. With reference to charts, he explained the intended route as up the Kern River Valley. He noted that they did not have any particular destination in mind; they were just going to enjoy the sights of the Sierra's. At the time he thought they may or may not go as far north as Mammouth Lakes, and might turn east before that time and head towards the Owens Valley. The pilot stated that while flying up the Kern River Valley his altitude was 1,800 to 2,000 feet above the river [from 6,000 to 7,000 feet msl, based upon a review of an area aeronautical chart].
The pilot stated that he turned right at a fork in the river which leads up to Jordan Hot Springs and the accident site canyon about 12,000 feet msl [the accident site elevation is 8,600], and over the surrounding ridges. The intention was to cross the Sierras at that point and then back to the Owens Valley. The pilot noted that he had been in the area around Kern Peak before and was familiar with the terrain. Nearing the accident site area, the aircraft began to experience a small amount of light chop-type turbulence, and then suddenly the aircraft was violently rolled and yawed to the right by very strong turbulence. The pilot said he had the impression or feeling that the aircraft was being pushed forward and down towards the ground by some strong force. The aircraft was descending and the pilot managed to recover the aircraft to level flight just before colliding with trees.
In describing the general weather conditions encountered during the passage up the Kern River Valley, the pilot said he noted no clouds in the sky and the aircraft did not require any noticeable wind correction angle to maintain a straight ground track north along the river. Prior to the encounter over the accident site area, the flight did not experience any turbulence or other unusual meteorological phenomena.
Regarding the engine, the pilot reported that during the flight he did not perceive any deficiency; however, during the turbulence encounter, "the engine did not respond like I expected."
The pilot and sheriff's deputy who flew the accident pilot during the effort to relocate the crash site were interviewed. The pilot stated to them that he departed the Kernville airport about 1030 on November 27th with the intention of following the Kern River Valley north to the Mammoth Lakes area, then returning south in the Owen's Valley. At a fork in the river (later identified by the deputy as Nine Mile Creek), the pilot turned to the right instead of to the left. The pilot then turned left into a canyon later identified as Redrock Creek, which leads to the accident site. The pilot stated to the deputy and the search pilot that the terrain rose rapidly and a downdraft pushed the aircraft into trees.
The accident site is in a box canyon at 8,300 feet msl. The floor of the canyon rises steeply from the entrance about 3,000 feet in 3 miles. The surrounding ridge tops which form the box rise to elevations in excess of 11,000 feet msl.
The historical aircraft maintenance records and FAA aircraft registry files were examined. The Maule M-5-235C airframe, serial number 7218C, had accrued a total time in service of 1,748 hours. The engine was a Lycoming O-540-J1A5D, serial number L-20116-40A, which was the original Maule factory installed power plant. The last annual inspection was accomplished on June 28, 1994, at 1,673 hours total time.
Review of the engine maintenance records disclosed that the engine had never been overhauled, and with no record of work performed on the camshaft. The number 1 cylinder was removed and replaced due to low compression on January 5, 1988, at a total time of 825 hours. Cylinders 2 and 6 were removed and replaced on April 7, 1991, at a total time of 1,223 hours.
The fuel system consisted of two main and two auxiliary fuel tanks, for a total usable capacity of 63 gallons. Fueling records at the Lone Pine, California, airport revealed that the aircraft purchased fuel on November 19th; however, no record of a purchase was found on the day of the disappearance. The last documented fueling of the aircraft was at the California City airport on November 27th with the purchase of 51.97 gallons of 100 LL aviation fuel.
Examination of Maule Aircraft manufacturing records disclosed that the aircraft was originally delivered on July 5, 1978, with a Emergency Beacon Corporation model EBC 102A ELT. At the accident site, the aircraft was found equipped with a Narco model ELT 10, serial number 30385.
Detailed review of the aircraft maintenance records disclosed no entry denoting the removal of the EBC 102A and installation of the Narco ELT 10. Review of the historical aircraft equipment lists showed that the first list with the Narco ELT 10 denoted as installed was dated December 3, 1980.
Maule Aircraft was contacted and an engineering representative stated that both the EBC 102 and Narco ELT 10 are factory options available to buyers. Both ELT's are approved for installation in the airframe under the Type Certificate approval. The EBC 102A is a self-contained unit and requires no external antenna. The Narco ELT 10 does require an external antenna connection. According to the representative, the installation drawings have not changed since production of this aircraft. Copies of the drawings were provided to the Safety Board.
Both the EBC 102A and Narco ELT 10 are mounted under the left front seat. In the Narco ELT 10 installation, a coaxial antenna cable is routed under the carpet to the left front door post, then up the post to the left wing root and the external antenna. The external antenna is mounted on the metal wing root fairing about 2/3 of the wing cord line.
After recovery of the aircraft, the airframe was examined for evidence of the external ELT antennae provisions required for installation of the Narco ELT 10 under the approved Maule Type Certificate drawings. No evidence of a coaxial cable installation was found. The wing root fairings showed no evidence that an external antennae had ever been mounted.
FAA airman record files were reviewed for the occupants. The seating positions noted in the following section of this narrative were determined from a review of the videotape recovered from the wreckage as noted previously.
The aircraft owner was seated in the left front and holds a private pilot certificate with an airplane single-engine land rating. The most recent certificate was issued on April 22, 1994. In addition, he holds a third-class medical certificate which was issued with a waiver for defective color vision on April 5, 1993.
The first passenger holds a private pilot certificate with airplane single-engine land and instrument ratings. The most recent certificate was issued on August 4, 1994. In addition, he holds a second-class medical certificate which was issued on August 2, 1994, with the limitation that correcting glasses be worn while exercising the privileges of his airman certificate. He was found outside the aircraft by search and rescue crews, and review of the previously noted videotape revealed that he was seated in the back.
The second passenger holds no airman certificates or ratings of record. Associates reported that he has no known aeronautical experience. The videotape disclosed that he was seated in the right front seat.
The accident site is in the Sierra Nevada Mountains on the south face of Kern Peak at an elevation of 8,300 feet msl. The mountain range runs generally on a northwest to southeast line and separates the greater San Joaquin and Owens Valley's. There are no official weather observation stations in the area of the accident site. The closest stations were identified as (all distances referenced are statute miles and directions are from the accident site): Bishop 75 miles north; Fresno 85 miles west; Inyokern and NAS China Lake 53 miles southeast; and Mammouth Lakes 95 miles northwest. Bishop, Inyokern, and NAS China Lake are in the Owens Valley at elevations which range from 4,100 to 2,200 feet. Mammouth Lakes airport is at 7,128 feet. Fresno is in the San Joaquin Valley at an elevation of 333 feet.
Weather reports were obtained from the National Weather Service (NWS) covering the period from 1030 through 1530 on November 27. The hourly surface observations during the stated time period for Fresno, Bishop, Inyokern and NAS China Lake reported generally scattered clouds from 10,000 to 20,000 feet agl, with winds below 10 knots velocity. The winds at Inyokern and China Lake were calm, while Bishop was reporting southeasterly winds at 8 to 10 knots. A pilot report on the ground at Mammouth Lakes airport at 0927 reported surface winds from 130 degrees at 4 knots.
The stations at Bishop and Fresno report winds aloft to the system for forecast purposes. The 1032 winds aloft observation reported by Bishop for the msl altitudes of 9,000, 12,000 and 18,000 feet were: 320 degrees at 23 knots; 320 degrees at 37 knots; and 310 degrees at 63 knots. The observations reported by Fresno for the same altitudes consisted of: 320 degrees at 30 knots; 310 degrees at 41 knots; and 310 degrees at 64 knots.
Pilot reports of weather conditions aloft were examined. Over Hawthorne, Nevada (east of Bishop) at 16,000 feet at 1028, the flight conditions were reported as smooth with no turbulence. A pilot at 9,500 feet on a track line from Bakersfield to Lancaster reported smooth flight conditions at 1021. Smooth flight conditions were also reported at 1105 by a pilot over Mammouth Lakes at 14,500 feet. At 1216, a pilot flying a track line from Fresno to Bishop at 17,500 feet reported smooth flight conditions with observed winds from 310 degrees at 20 knots.
WRECKAGE AND IMPACT INFORMATION
The accident site is in the Sierra Nevada Mountains on the south face of Kern Peak at an elevation of 8,300 feet msl. In a bowl shaped box canyon, the site is populated by large pine trees which range from 40- to 70-feet tall.
A path of disturbed trees and wreckage components were noted on a magnetic bearing of about 320 degrees over a distance of 225 feet. Four trees were noted with either disturbed branches or sections of the tops removed; the tree limb and trunk breaks appeared fresh. Several aircraft skin components and the outboard 1/3 of the right wing were noted to be in the upper portions of the trees (see wreckage diagrams for detailed locations).
The aircraft was observed nose down in the snow at approximately a 70-degree angle with the fuselage oriented on a 150-degree magnetic bearing. The engine was half buried in a creek bed frozen into the ice and could not be moved.
The aircraft was removed from the accident site by helicopter on December 30, 1994, and examined in detail at a storage facility at the Santa Paula airport on January 18, 1995. The engine and propeller were frozen into ice at the accident site and could not be removed from the location or examined in place.
Both wings exhibited extensive leading edge damage, with semicircular indentations and botanical material transfer noted. The right wing forward lift strut exhibited a circular indentation about midspan; the indentation appeared to have a diameter of about 10 inches. The outboard 1/3 of the wing was separated and observed in the top of a large pine tree back along the wreckage distribution path at the accident site. The main spar at the separation point was bent rearward at about a 40-degree angle. The associated auxiliary fuel tank for the missing outboard section was found at the base of one of the pine trees. The aileron separated from the wing and was found in one of the pine trees; the unit separated from the wing at the hinge points with overload characteristics evident. The flap remained attached to the wing.
The left wing leading edge is more extensively damaged than the right one. The wing is intact from root to tip rib. The rearward crush deformation extends to the rear spar area. The aileron and flap remained attached to their associated hinge assemblies.
With the exception of the left elevator, the empennage fixed and moveable control surfaces remained attached to the structure. The vertical stabilizer and rudder are not damaged. The right horizontal stabilizer and elevator are not damaged. The left horizontal stabilizer was damaged on the outboard 1/2 of the span, and was bent down. The elevator separated from the stabilizer and was found in one of the pine trees; the separations exhibited overload characteristics.
Flight control cable continuity was established from the front seat area aft to the empennage, and from the wing root ribs to the ailerons.
The front seats remained attached to their respective rails and exhibited rearward and down loading on the legs and seat backs. The shoulder harnesses for the front seats were cut near the buckle fitting. The webbing showed no evidence of stretching or loads on the material at either the attach fitting or near the severed portion.
The right front seat belt was cut by rescue personnel to remove the passenger. The belt webbing does not exhibit any evidence of stretch or loading at the attach point.
Neither the left front seat belt nor the rear seat belts exhibit evidence of stretch or loadings.
The Emergency Locator Transmitter (ELT) was found under the left front seat secured in its associated mounting bracket. The unit switch was found in the off position. No external antennae wire was found.
Frontal crush in a rearward and right direction was observed on the cabin structure.
TESTS AND RESEARCH
The ELT was removed from the aircraft for a detailed functional test at an FAA approved avionics repair facility at the Van Nuys airport. The test was supervised by an FAA airworthiness inspector. According to the facility, the ELT functioned correctly; however, produced a weaker than normal signal.
The engine was removed from the accident site on June 18, 1995, and initially examined on June 21 at the Santa Paula wreckage storage facility.
Both propeller blades remained in the hub and exhibited torsional tip end twist deformation, leading edge damage, and chordwise scoring signatures. One blade exhibits more extensive damage patterns than the second.
The engine was intact, with no external evidence of catastrophic failure noted. Small pieces of pine tree branches, mud, and other organic debris were found jammed in-between the cylinders. The throttle arm on the carburetor was in the idle position. The mixture arm was noted in a midrange location.
The bottom spark plugs were removed and noted to be of the fine wire type. All six were corroded, with deposits of water, mud, and other debris observed. Water was found in all cylinders, and in the intake and exhaust tubes.
The propeller governor exhibited impact damage. Removal from the engine case mounting pad revealed a clean screen.
The crankshaft rotated easily by hand. Compression was noted in all cylinders. Accessory gear and valve train continuity was established. During the test, observation of rocker arm movement revealed the intake valves for the number 1 and 2 cylinders did not lift as much as the others by about 0.125 inches.
The number 1 cylinder was removed from the engine for detailed examination. The valve heads, cylinder chamber, and piston domes exhibited normal signatures. The piston pin caps were worn and tapered in appearance. The cam lobe and lifter body for the intake valve were spalled. Minute metal flakes were observed imbedded in the connecting rod bearing. Small ferris metal flakes were found in the oil sump, suction screen, and oil filter element.
The fuel pump was removed from the engine and disassembled. All diaphragms and springs were intact. Internal examination of the carburetor revealed no abnormalities with the floats, float bowl, needle valve, venturi or nozzle.
The dual magneto was removed. Hand rotation produced a strong spark from all ignition leads on one side; however, only intermittent sparks could be obtained from the other side at certain leads.
Due to the outdoor and contaminated nature of the salvage yard location, the examination was terminated, and to be continued at a more controlled overhaul facility. The engine examination continued on February 29, 1996, at Lynn's Aircraft Engines in El Monte, California. Following removal from the sealed packing crate, the engine appearance was examined and found to be consistent with the engine condition when the first examination was terminated.
The oil sump and accessory case was removed from the case assembly. All accessory gears appeared normal. Cam timing was noted to be correct.
The oil pump was disassembled. Rust was noted on one impeller gear. Small metal particles were noted in the oil pump housing. Scoring was noted on the housing wall.
All remaining cylinders were removed from the case. The piston pins on numbers 2 and 6 were observed to be of the piloted type, while the pins for numbers 1, 3, 4, and 5 were of the plug type. Lycoming Service Instruction 1267B states that the two types of pins cannot be mixed. No unusual operating signature was observed on the pin bodies. The pin plugs on numbers 1, 3, 4, and 5 are scored around their circumference; the scoring appears to be heavier on 1, 3, and 4.
No unusual operating signature was noted internally to any cylinder. All valve heads, valve stems, cylinder chambers, and piston domes exhibited normal signatures.
The case was split and the camshaft and lifter bodies exposed. The cam lobe representing the numbers 1 and 2 intake valves was spalled. The corresponding lifters were spalled and pitted. Minor spalling signatures were observed on all remaining lifters. Minor corrosion deposits were noted on the lifter shafts.
All cam lobes were measured in comparison to a factory drawing and the results are presented in the following table:
INTAKE LOBES (All measurements are in inches)
Cylinder # Base Circle Dia. Tip Cord Cam Lift
Drawing Spec 1.130 1.480 0.350 1 & 2 1.1385 1.3819 0.2434 3 & 4 1.1388 1.4872 0.3484 5 & 6 1.1376 1.4867 0.3491
EXHAUST LOBES 1 1.1248 1.4767 0.3517 2 1.1278 1.4783 0.3505 3 1.1220 1.4780 0.3560 4 1.1228 1.4787 0.3559 5 1.1221 1.4783 0.3562 6 1.1214 1.4780 0.3566
All bearing surfaces exhibited normal operating signatures. No other internal abnormality was noted.
The camshaft and the tappet for the numbers 1 and 2 cylinders (intake and exhaust) were retained for further detailed metallurgical examination. The components were submitted to Fowler, Inc., Gardena, California. The metallurgists report of the examination is appended to this report.
According to the metallurgists report, the tappet bodies and camshaft were chemically consistent with the Lycoming specified proprietary alloy. Hardness and case depth values were within drawing specifications. Corrosion pits and cracks were observed on the cam lobes and tappet faces. In his report, the metallurgist stated: "The presence of corrosion pits on the lobe and bearing surfaces would indicate that prior corrosion had occurred which provided a site for crack initiation...[and]...created the spalled appearance that was especially severe on the No. 1 and 2 intake lobe and the No. 1 and 2 tappet body faces."
The airframe wreckage was verbally released to the representative of the owner at the conclusion of the examination on January 18, 1995. The engine was released on February 29, 1996, at the conclusion of the examination. The camshaft and lifters retained were returned to the storage yard on May 14, 1996.