Truckee, CA, USA
N62792
PIPER PA23
The pilot reported that before takeoff he performed his normal engine run-up and all checks were normal. After taking off, and while between 70 to 100 feet above the ground, he felt a vibration in the left engine, which was running rough. The pilot stated that he checked the engines and attempted to reduce power but that he didn’t have sufficient time to react. The airplane subsequently rolled to the left. He described the event as a "classic VMC stall." During the postaccident examination of the left engine, foreign debris was found in the No. 2 fuel nozzle, which most likely caused the engine to run rough. However, even though the left engine may have been running rough and not producing full takeoff power, the right engine was operating properly, and, if the pilot had maintained the airspeed at or above the airplane’s minimum controllable airspeed, he should have been able to maintain control. The pilot’s failure to maintain the airspeed resulted in the uncontrollable left roll and subsequent impact with the ground.
HISTORY OF FLIGHT On September 21, 2011, about 0922 Pacific daylight time, a Piper PA-23-250, N62792, sustained substantial damage after impacting terrain following a loss of control during initial climb after takeoff at the Truckee-Tahoe Airport (TRK), Truckee, California. The airplane was registered to and operated by the pilot in accordance with Title 14 Code of Federal Regulations Part 91. The private pilot, sole occupant of the airplane, sustained serious injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight. The flight was originating at the time of the accident, with a destination of Bakersfield, California. In a report submitted to the National Transportation Safety Board investigator-in-charge (IIC), and in a telephone interview with the IIC, the pilot reported that after the airplane had been fueled and the baggage loaded, he performed a preflight check of the airplane; everything looked normal. The pilot stated that he started the engines without difficulty, and taxied to the runway, performed his standard runway checks, and proceeded to take off. Upon reaching an altitude of about 70 to 75 feet [above ground level (agl)], with the landing gear still extended, he felt a vibration, and that the left engine was running rough. The pilot stated that he didn’t have time to react to reduce power on the right engine, which was why the airplane rolled over to the left. The pilot described the event as a “Classic VMC stall,” which resulted in the airplane impacting terrain and being consumed by a post crash fire. According to an airport employee who witnessed the accident, the airplane initially climbed to an altitude of between 50 and 100 feet agl before it began to veer to the left. The airplane then simultaneously pitched up to about a 30-degree angle, and then entered a left-wing-down, nose down attitude. The airplane subsequently impacted terrain with its left wing and cart wheeled before coming to rest on the airport's west parking ramp in an upright position. A post crash fire consumed the cabin and cockpit areas. The left wing was observed separated, while the empennage remained intact. The wreckage was recovered to a secured location for further examination. PERSONNEL INFORMATION The pilot held a private pilot certificate with ratings for airplane single-engine land and, airplane multiengine land. The pilot reported a total time of 2,000 hours of flight time, with 400 hours multiengine time, all in the accident airplane. The pilot's most recent biennial flight review was completed in the accident airplane on May 21, 2011. A review of Federal Aviation Administration (FAA) medical records revealed that the pilot’s most recent third-class airman medical certificate was issued on June 29, 2009, with the limitation “must wear corrective lenses.” AIRCRAFT INFORMATION The airplane was manufactured in 1976. According to maintenance records provided by the pilot, the most recent annual inspection was performed on May 23, 2011, at a total airframe time of 4,760.5 hours. The airplane was equipped with two Lycoming IO-540-C4B5 six cylinder, air cooled, direct drive, horizontally opposed, normally aspirated (fuel injected), internal combustion engines, rated at 250 horse power at 2,575 revolutions per minute. Both engines underwent annual inspections on May 23, 2011, at which time the right engine had accumulated 560.7 hours since its most recent major overhaul, while the left engine had accumulated a total of 690.8 hour since its most recent major overhaul. METEOROLOGICAL INFORMATION At 0855, the weather reporting facility located at the Truckee-Tahoe Airport, indicated wind calm, visibility 10 miles, sky clear, temperature 9 degrees Celsius (C), dew point 3 degrees C, and an altimeter setting of 30.27 inches of mercury. WRECKAGE AND IMPACT INFORMATION The airplane came to rest about 500 feet south of runway 28/10, and oriented facing north and nearly perpendicular to the active runway. The airplane remained in an upright position and basically intact, with the exception of the left wing, which had separated. The forward cabin/cockpit area was consumed by a post crash fire. The fuselage sustained extensive ground impact fire damage. The engine controls were observed separated and mostly destroyed by fire damage. The center console fuel selector lever revealed that both left and right tank selectors were in the outboard tank position. The crossfeed selector was in the OFF position. The vertical tail surfaces remained attached to the rear empennage. Both the vertical stabilizer and rudder surfaces sustained some thermal damage, but were otherwise undamaged. The left wing separated during the impact sequence. The fuel gascolator and fuel selector valve remained partially attached to the main spar section, but had sustained thermal and impact damage. The aluminum fuel lines of the valve and fuel bowl were mostly consumed. The fuel bowl sustained extensive heat damage. The fuel selector valve has a lever that was positioned in the outboard fuel tank position. The cable wire that attached to the lever remained attached. The wire was extended out of the outer cable housing, curved and bent consistent with the valve lever being in the outboard tank position. The right wing was separated from the fuselage, and was mostly consumed by fire. The fuel gascolator and fuel selector valve remained partially attached to the main spar section, but had sustained heat impact damage. The aluminum fuel lines of the valve and fuel bowl were mostly consumed. The fuel bowl sustained extensive heat damage. The fuel selector valve has a lever that was positioned in the inboard fuel tank position. The cable wire that attaches to the lever was broken and separated. Both engines and propellers were recovered from the accident site for further examination. TESTS AND RESEARCH An examination of both engines and associated propellers was performed at the facilities of Plain Parts, Pleasant Gove, California, on November 10, 2011. The examination was overseen by the NTSB IIC. Left engine The fuel injection servo was displaced from the engine, and the portion that remained attached at the mounting pad was secure. The fracture surface signatures were consistent with overload. The throttle/mixture controls were found securely attached at their respective control arm of the servo. The plug on the side of the injector body was secure with the safety wire in place. The servo fuel inlet screen was found properly installed and free of contamination. The fuel injection servo and induction system were examined and observed to be free of obstruction. The fuel injection servo’s metering diaphragm section cover exhibited a puncture induced by the mixture control lever during the impact sequence. The internal diaphragm remained intact. The fuel flow divider remained secure at the mounting bracket situated at the top of the engine. The fuel lines remained secure at each flow divider fitting and fuel injector at each cylinder. The flow divider was disassembled. There was no evidence of internal mechanical malfunction or obstruction to fuel flow. The diaphragm remained intact and undamaged. The fuel pump was attached to the engine at the mounting pad. The fuel lines remained secure at their respective fittings. The fuel pump was removed for examination. The fuel pump remained free of internal mechanical malfunction and obstruction to flow. The diaphragm remained intact. The fuel injection nozzles remained secure at each cylinder with the respective fuel line attached. The nozzles were removed and examined. The number five & six nozzles were the two piece type with the remainder being the one piece style. Examination of the nozzles found that the number two cylinder nozzle appeared partially obstructed at the discharge end. The fuel nozzles were retained by the NTSB IIC and forwarded to Precision Airmotive for further examination. The examination was conducted on November 28, 2011, at Precision’s facility in Marysville, WA. According to the attached Precision Airmotive report 092111, the number two nozzle was plugged with “black debris,” which was removed utilizing 0.015 wire. The piece of foreign material extracted from the subject nozzle during the Precision examination was subsequently analyzed by the NTSB Materials Laboratory, Washington, D.C. An NTSB chemist reported that the material was examined using a Fourier-transform infrared (FTIR) spectrophotometer. The chemist further reported that the resulting spectrum from the unknown material was compared against a spectral library of known materials and that the closest spectral match was paint. A known sample of torque stripe paint analyzed in a prior unrelated accident found that the spectrum from the accident sample and the known torque stripe paint were a very strong match. The two bladed constant speed propeller remained attached at the crankshaft flange. The spinner was attached to the propeller. The propeller blades remained attached to the propeller hub. Both propeller blades were bent aft about 40-45 degrees about ¾ distance of the blade. The propeller governor was securely attached at the mounting pad with the pitch control rod securely attached at the control wheel. The governor was not removed for examination. Right engine The engine remained attached to the firewall by the engine mount. The engine had sustained moderate thermal damage to the rear area of the engine resulting from the ensuing post impact ground fire. Visual examination of the engine revealed no evidence of pre-impact catastrophic mechanical malfunction or fire. The left and right magnetos remained securely clamped at their respective mounting pads. The ignition harness was secure at each magneto. Magneto to engine timing could not be ascertained. The magnetos were not removed for examination. There was no comprehensive disassembly beyond the cursory visual examination of the subject engine. The two bladed constant speed propeller remained attached at the crankshaft flange. The spinner was attached to the propeller. The propeller blades remained attached to the propeller hub. The propeller blades displayed leading edge gouging, chordwise striations across the cambered surface and trailing edge “S” Bending. The signatures were consistent with the absorption of rotational forces applied at the crankshaft at the time of impact. The propeller governor was securely attached at the mounting pad with the pitch control rod securely attached at the control wheel. The governor was not removed for examination. ADDITIONAL INFORMATION According to the Federal Aviation Administration’s Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25A), Vmca is defined as minimum control speed in the air, with one engine inoperative (critical engine on two-engine aircraft) operating engine(s) at takeoff power, maximum of 5° bank into the good engine(s).
The pilot's failure to maintain an airspeed at or above the airplane's minimum controllable airspeed, which resulted in a loss of airplane control. Contributing to the accident was the partial loss of power from the left engine as a result of a clogged fuel nozzle.
Source: NTSB Aviation Accident Database
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