KERNVILLE, CA, USA
N6654A
Piper PA-34-200T
Seconds after takeoff, the engines lost partial power. Witnesses saw black smoke trailing from the airplane. Unable to climb, the pilot ditched and sank in 20-foot-deep water, 1.25 miles from the airport. During the month preceding the accident, black smoke had been observed trailing from the airplane on two other occasions, but no evidence of maintenance was noted in the logbooks. The airplane was recovered and examined. The engines were placed into a test cell and run and numerous maintenance related deficiencies were found. Although full power was obtained, the fuel flow rates to both engines exceeded design specifications, thus creating overly rich mixtures and black smoke. Additionally, the right engine's left magneto internally arced, and 5 of the 12 spark plugs were worn beyond limits. The density altitude was computed at 4,300 feet. Also, the maximum certificated gross weight was exceeded by at least 160 pounds, and the center of gravity was 1.09 inches aft of the rear limit. The pilot said he had not asked for a weather briefing prior to departure, nor had he performed weight and balance computations. The fare-paying passengers had not been advised to secure their shoulder harnesses prior to takeoff, and their aft loaded baggage was unsecured because of the previous removal of the tie down straps. The pilot did not provide the Safety Board with evidence of his recent flying currency or complete the required report form. The passengers chartered the flight in response to the operator's yellow page advertisement for such availability. The operator did not possess a 14 CFR 135 certificate, and the FAA's surveillance of the FBO was nil.
HISTORY OF FLIGHT On August 17, 1997, at 1744 hours Pacific daylight time, a Piper PA-34-200T, N6654A, operated by the Aero Club, Van Nuys, California, experienced a partial loss of engine power during takeoff from runway 17 at the uncontrolled Kern Valley Airport, Kernville, California. Witnesses reported observing black smoke trailing from the airplane during its initial climb. The pilot reported that the airplane failed to climb or adequately increase airspeed, so he elected to ditch into Isabella Lake, about 1.25 miles south of the airport. The airplane sank in about 20-foot-deep water and was destroyed. The airline transport pilot and three passengers sustained minor injuries. The fourth passenger was seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the flight. The pilot reported to the Safety Board that on Friday, August 15, he flew the passengers from Van Nuys to Kernville. By prior arrangement, he was to pick up the passengers 2 days later and fly them back to Van Nuys. On August 17, the pilot flew the airplane in solo flight from Van Nuys back to Kernville. The flight lasted about 0.9 hours and was flown at 180 miles per hour (mph) at a cruise altitude of 8,500 feet mean sea level (msl). The pilot reported that he landed at Kernville about 1730. The passengers were all waiting for the pilot at the airport for their return flight home. The passengers boarded the airplane, and according to the pilot, no instructions were given on how to fasten their seat belts because the "passengers had previously been briefed on seat belt operation . . . ." The pilot further stated that "after a couple of attempts a hot (engine) start was performed," which was followed by running up the engines "to verify that all were in operating condition." The pilot verbally reported that although he did run-up both engines to 2,000 rpm and tested their magneto rpm drop, which was each between 50 and 100 rpm, he did not cycle the propellers. The pilot reported he then taxied to the approach end of the runway and tookoff with both mixture controls in the full rich position. According to the pilot, during the takeoff roll the airplane's acceleration appeared normal, and he rotated at 100 mph. The airplane further accelerated to 120 mph while climbing 100 feet. Then, the engines sounded as though they had reduced their power to half. The pilot reported that he responded to the situation by retracting the landing gear, and attempting to restore engine power. He verified that both fuel valves were on, the mixture, propeller, and throttle controls were full forward, the auxiliary fuel pump switches were off, and the magneto switches were on. The fuel pressure gauges for both engines indicated "0" pounds of fuel pressure. The pilot further reported he then moved the left engine's auxiliary fuel pump switch to the "on" and "off" position two times, and the engine developed (more) power. The left engine's fuel pressure gauge then "registered full fuel pressure." The pilot attempted the same procedure with the right engine, but as soon as he turned the auxiliary fuel pump switch "on" the engine made a distinct sputtering sound, so he switched the pump off. The pilot maneuvered around a hill, and the airplane continued descending and losing airspeed. The pilot verbally reported that throughout the flight both engines continued operating, and the propellers rotated between 2,400 and 2,450 rpm. The pilot indicated that he elected to ditch in the water rather than to lose control of the airplane. INJURIES TO PERSONS The left rear seat passenger was the only seriously injured occupant. This passenger was located in front of the aft baggage compartment. The other five occupants received minor injuries. PERSONNEL INFORMATION By letter dated August 27, 1997, the Safety Board requested that the pilot complete the required Aircraft Accident Report Form, No. 6120.1/2, and submit for inspection his personal flight records. On October 20, 1997, through the pilot's counsel, a flight record logbook was submitted. An examination of the logbook revealed the pilot's flying activities between 1989 and August 1992. No more recent flights were noted. The pilot's counsel indicated that the pilot would search for additional evidence of more recent flight activity, and he would provide the evidence when located. As of July, 1998, neither additional documentation nor the 6120.1/2 form have been received by the Safety Board. Accordingly, the pilot's recent flying experience and currency pertinent to the accident flight could not be established. AIRCRAFT INFORMATION Fuel Pump Switch Design. The pilot verbally reported that the airplane's auxiliary fuel pump rocker type switches had only two positions. The switches could be set to either the "on" or the "off" position. The Safety Board's examination of the accident airplane's fuel pump's switches revealed that they were designed with three positions, as follows: "low," "high," and "off." Positioning the switches into the "high" position first required moving a guard cover away from the switches. Aft Baggage Compartment Tie Down Straps. During an August 18, 1997, interview with the right front seated passenger, he reported that no one secured the two bags which he observed placed into the aft baggage compartment just behind the rear seats. According to the airplane's flight manual, the aft baggage compartment was equipped with tie down straps. An examination of the airplane revealed the presence of four bolt-sized holes beneath the carpeted baggage compartment floor. No tie down straps were located. The Piper participant reported that the "bolt holes" appeared to be located where bolts/tie down straps had once been installed. No other device was observed in the baggage compartment area for securing the passenger's luggage. Weight and Balance Computation. The pilot reported that he did not compute the airplane's weight and balance prior to taking off from Kernville. He simply performed a visual estimate for the weights of the passengers and their baggage. The pilot stated that he has never used the Airplane Flight Manual which he believed was carried in the airplane. Weight and Balance Computation. The Federal Aviation Administration (FAA) certificated maximum gross weight for the airplane is 4,570 pounds. The aft center of gravity (CG) limit at that weight is 94.6 inches. Based upon weight and balance data provided by The New Piper Aircraft, Inc., the weights of the occupants and their baggage, and the estimated fuel onboard, the Safety Board calculated that upon departure the airplane's gross weight was not less than approximately 4,730 pounds, and its CG was about 95.69 inches aft of datum. History of Black Smoke. The Safety Board interviewed the two pilots who had flown together in the airplane immediately prior to the accident pilot's flights. They reported that between approximately July 17 and August 10, 1997, they had taken off from the Van Nuys Airport. During departure, control tower personnel alerted them that black colored smoke was observed trailing from the airplane. The pilots leaned the mixture control(s) and made a low pass by the tower. No further evidence of smoke was reported, and they continued their flight without mishap. On August 15, 1997, as the accident pilot was departing from Kernville, two of the passengers which had just exited the airplane observed black smoke trailing from the airplane. On August 17, when the accident pilot returned to Kernville to transport the passengers for the return (accident) flight to Van Nuys, one of the passengers informed the pilot of his earlier observations. The passenger reported to the Safety Board that the pilot had similarly observed the black smoke during his previous departure. On August 21, 1997, the pilot acknowledged to the Safety Board that he had observed the left engine's black smoke during his August 15 flight with the passengers. He stated that the smoke "cleared itself after 5 to 7 seconds on takeoff." The pilot further stated that upon landing back at Van Nuys, he had mentioned the occurrence to the operator. Two witnesses, located at the Kernville Airport, reported observing black smoke trailing from the airplane during its initial climb on the accident flight. One of the witnesses was an airplane mechanic. This witness also indicated that as the airplane departed it made a noise like an engine was sputtering, and one or both of the engines sounded rough running. Maintenance. An examination of the airplane's maintenance records did not reveal evidence of any maintenance performed since the last 100-hour inspection on July 2, 1997. Since that date, the airplane had been operated for about 80 hours. METEOROLOGICAL INFORMATION The pilot reported that he did not receive a weather briefing prior to the flight. Two of the passengers reported that while at the airport, just prior to takeoff, they observed a thermometer which indicated the outside air temperature was between 94 and 96 degrees Fahrenheit. Another passenger estimated that the temperature was between 85 and 90 degrees Fahrenheit. A witness, located adjacent to the airport, estimated that the temperature was between 86 and 90 degrees Fahrenheit. Based upon this 11-degree maximum temperature range, the Safety Board calculated the approximate density altitude was 4,300 feet, plus or minus 300 feet. WRECKAGE AND IMPACT INFORMATION The airplane was examined immediately following its recovery from the lake. The airframe was found mostly intact, and all flight control surfaces remained attached to their hinges. The left wing, the rudder, and the stabilator were found securely attached to the fuselage. The right wing was found attached to the airframe by the aileron control cables. Except for evidence of water intrusion, the cockpit and cabin areas appeared mostly undamaged. Control continuity was confirmed between all flight control surfaces and the pilot's yoke and rudder pedals. There was no evidence of fire. SURVIVAL ASPECTS On August 21, 1997, the pilot verbally reported to the Safety Board that he did not direct that the passengers fasten their shoulder harnesses prior to takeoff from Kernville. He stated that he did not use his shoulder harness because he had become "sloppy." In fact, he did not know that the airplane was equipped with shoulder harnesses. During the Safety Board's examination of the airplane, shoulder harnesses were found installed at all seats except for the two aft facing seats in the middle of the airplane. The front left seat harness (referred to as the pilot's harness) was found secured to the overhead ceiling storage clip. The harness was in a folded and stowed position. TESTS AND RESEARCH Under the Safety Board's supervision, both engines and propeller assemblies were transported to the Teledyne Continental Motors (TCM) factory for examination and functional testing. Several maintenance related discrepancies were observed with the engines, including discrepancies involving fuel flow rates and electrical system components. See the attached participants' reports for a detailed description of the findings. In pertinent part, both engines were successfully test run and operated in the test cell. During application of full power, the left and right engines' fuel flow measured 151 and 160 pounds per hour (pph), respectively. The design specification is for a flow rate between 130 and 140 pph. Manual adjustment of the left engine's fuel pump aneroid was necessary to reset the fuel flow rate to specifications. When the left engine's fuel flow exceeded the limits, black smoke emitted from the tail pipe; however, rpm and manifold pressure were maintained. An examination of the left magneto on the right engine revealed evidence of electrical arcing signatures in the distributor block. The arcing left corrosion residue and etched a path in the side of the terminal. The spark plug gaps were measured. Five of the 12 plugs were found with gaps of 0.025 inches and were classified by TCM as worn. The nominal gap is 0.019 inches. TCM opined that the discrepancy with the magneto did not appear to degrade performance when operating at sea level atmospheric pressure. Arcing would occur when operating at reduced pressure. ADDITIONAL INFORMATION Airplane Charter. In searching for air transportation between Van Nuys and Kernville, the wife of one of the prospective passengers reported to the Safety Board that she had noticed an advertisement in the local telephone book yellow pages. In follow up to the advertisement, captioned "Aircraft Charter & Rental Service," the wife contacted the operator. The wife spoke with the pilot who indicated that an airplane flight could be chartered from the Aero Club for the requisite round trip transportation. The total fare, payable in advance, would be $500, which could be made by check or a major credit card. On August 18, 1997, the Aero Club's owner/operator reported to the Safety Board that the accident pilot works there. The pilot was authorized to fly the accident airplane which the Aero Club operates and maintains. In addition to flying, part of the pilot's job is to sit at the front office desk and answer the telephone to schedule flights. The Aero Club has not been issued an FAA air carrier operating certificate to perform on-demand charter flights pursuant to 14 CFR 135. FAA Surveillance. The Aero Club's fixed base operation is located next to the base of Van Nuys Airport's Air Traffic Control Tower, a few blocks from the FAA's Flight Standards District Office (FSDO). FSDO inspectors verbally reported to the Safety Board that they were unaware the FBO was advertising charter flight availability in the local telephone book. FSDO personnel further reported that because the FBO does not hold a 14 CFR 135 air carrier operating certificate, its surveillance of the operator is nil. Wreckage Release. The entire airplane wreckage was verbally released to the owner's assigned insurance adjuster on February 26, 1998.
The partial loss of engine power due to the operator's inadequate engine maintenance relating to excessively rich mixtures (high fuel flow rates) and spark plug/magneto deficiencies. Contributing factors were degraded climb performance resulting from the high density altitude and the airplane loading which exceeded maximum weight and aft center of gravity limits.
Source: NTSB Aviation Accident Database
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