CEN15FA425

The separation of the attachment hardware connecting the elevator trim tab pushrod to the elevator trim actuator, which resulted in the elevator trim tab jamming in a position outside the limits of normal travel and a subsequent loss of airplane control.

The commercial pilot was departing on a personal cross-country flight in the airplane. During initial climb after takeoff, witnesses saw the airplane suddenly pitch down into a rapid descent that continued to ground impact. Postaccident examination revealed that the elevator trim pushrod was attached to the trim tab but not attached to the trim tab actuator. The bolt, nut, and cotter pin securing the elevator trim tab pushrod to the actuator were missing and not recovered. Examinations of the elevator and the pushrod revealed that the pushrod became jammed aft of the forward elevator spar creating an abnormally large trim tab up (nose down) condition. Measurements taken from an exemplar airplane of the same make and model as the accident airplane indicated that the elevator trim tab deflection with the pushrod jammed aft of the forward elevator spar would be over three times the normal maximum trailing-edge-up deflection. The airplane nose-down pitching moment at this increased deflection would create a forward force on the control yoke that a pilot would likely not be able to overcome. Following the accident, the manufacturer issued a service bulletin that required the hardware securing the elevator trim pushrod be replaced and specified the hardware to be used. Subsequently, the Federal Aviation Administration issued an airworthiness directive that required compliance with the service bulletin. Although the pilot's toxicology results were positive for ethanol in muscle tissue, when detected only in the muscle tissue, ethanol is likely from a source other than ingestion. No medications or illicit drugs were found that could pose hazards to flight safety.

The Regional Forensic Science Center, Sedgwick County, Kansas, conducted an autopsy of the pilot. The cause of death was attributed to "multiple blunt force injuries." The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicology testing on specimens from the pilot. The toxicology results were negative for carbon monoxide, cyanide, and drugs. The toxicology was positive for ethanol detected in muscle tissue, and no ethanol was detected in the liver. The 1553 recorded weather observation at ICT, included calm winds, visibility 10 miles, scattered clouds at 6,000 ft , broken ceiling at 8,000 ft, broken ceiling at 12,000 ft, broken ceiling at 15,000 ft, temperature 29ºC, dew point 14ºC; barometric altimeter 30.06 inches of mercury. The pilot held a commercial pilot certificate with airplane multi-engine land, airplane single-engine land, glider, and instrument airplane ratings. No pilot logbooks were recovered during the investigation. The pilot's most recent Federal Aviation Administration (FAA) second-class medical certificate was issued on June 23, 2015, with the limitation: "must wear lenses for distant, have glasses for near vision." On his medical certificate application, the pilot reported that he had about 470 total hours of flight time. Impact marks at the accident site were consistent with a steep nose-down, right-wing-low attitude, with the right wingtip striking the ground first. The fuselage and wings came to rest on the west side of the creek in an inverted position with the right wing folded under the fuselage section. The fuselage from the aft baggage compartment through the tail section was intact but exhibited substantial impact damage. The fuselage forward of the aft baggage compartment through the cabin compartment was substantially damaged. The right and left engines were underwater, imbedded in the soil at the bottom of the creek. The right and left propeller assemblies, a section of the left wing including the left main landing, and the nose landing gear were found underwater in the creek bed. The landing gear actuator was found in the fully retracted position. The right elevator remained partially attached to its attachment points. The elevator was separated spanwise outboard of the elevator trim tab, and the inboard portion of the elevator was distorted. The trim tab remained attached to the elevator at its hinge. The elevator trim pushrod was found attached to the trim tab but not attached to the trim tab actuator. The bolt, washer, castellated nut, and cotter pin securing the elevator trim tab pushrod to the actuator were missing. The elevator trim actuator remained attached to its attachment point on the horizontal stabilizer and was extended about 5/8 inch, which corresponded to a position outside its normal limits. Flight control cable continuity was established for the rudder, right aileron, and elevators. The left aileron, all trim systems, and the right and left flaps exhibited control cable overload separations. The engines were recovered from the creek bed, rinsed with water, and examined on-scene. The engine examinations revealed no evidence of preimpact anomalies or malfunctions. The left engine's propeller flange was distorted. All six of the propeller bolts remained with the propeller flange, and the bolt threads contained remnants of the propeller hub threads. The propeller flange was manually rotated, and crankshaft and camshaft continuity were confirmed to the pistons. The left engine's magnetos were separated from their respective mounting pads but remained attached to the engine via the ignition harness. All of the ignition terminal ends remained attached to their respective sparkplugs. The magnetos and ignition harness were removed as were the top sparkplugs for each cylinder. The top sparkplugs were covered with mud, water, and oil. After being rinsed with freshwater, each electrode displayed a normal worn condition when compared to the Champion Aviation Service Manual (AV6-R). No internal, pre-accident anomalies were observed with the magnetos. The cylinders were photographed internally with a borescope. Each cylinder contained mud and water from the creek and exhibited normal combustion deposits. No preaccident anomalies were noted with the cylinders, valves, valve seats, rockers, or springs. The engine-driven fuel pump was attached to the back of the engine and its drive coupling remained intact. Manual rotation of the drive coupling while installed in the driveshaft resulted in rotation of the driveshaft with a gritty feel to the rotation, but no binding was noted. The fuel pump was disassembled, and no preaccident anomalies were noted with any of the internal components. The throttle body/fuel metering unit remained attached to the engine via the fuel line between the fuel pump and the metering unit. The metering unit fuel inlet filter was removed and no obstructions or blockage were noted, but mud and dirty water were observed. The metering unit was disassembled, and no preaccident anomalies were noted with the internal components. The fuel manifold valve was disassembled, and aviation gasoline, mud and water were noted in the manifold. No pre-accident anomalies were noted with the diaphragm, plunger, spring, or screen. The left propeller hub was fractured, and only two of the three blades were recovered with remnants of the hub remaining attached to one of the blades. The two blades displayed S-bending, and both were twisted toward low pitch. The right engine's propeller flange was distorted; five of the six propeller bolts remained with the propeller flange; and the bolt threads contained remnants of the propeller hub threads. The propeller flange was manually rotated, and crankshaft and camshaft continuity were confirmed out to each piston. The right engine's magnetos were separated from their respective mounting pads and only the right magneto was recovered from the creek bed. No internal, preaccident anomalies were observed with the right magneto. All of the ignition terminal ends remained attached to their respective sparkplugs. The ignition harness remnants were removed as were the top sparkplugs for each cylinder. The top sparkplugs were covered with mud, water, and oil. All electrodes displayed a normal worn condition when compared to the Champion Aviation Service Manual (AV6-R). The cylinders were photographed internally with a borescope. Mud, water, and combustion deposits consistent with normal operation were noted within each of the cylinders. No preaccident anomalies were noted with the cylinders, valves, valve seats, rockers, or springs. The engine-driven fuel pump was attached to the backside of the engine. The drive coupling was intact, and rotation of the drive coupling while installed in the driveshaft resulted in rotation of the driveshaft with no binding noted. The fuel pump was disassembled, and no preaccident anomalies were noted with any of the internal components. The throttle body/fuel metering unit remained attached to the engine nacelle. The metering unit fuel inlet filter was removed, and no obstructions or blockage was noted, but mud and dirty water were observed. The metering unit was disassembled, and no preaccident anomalies were noted with the internal components. The fuel manifold valve was disassembled, and aviation gasoline, mud and water were noted in the manifold. No preaccident anomalies were noted with the diaphragm, plunger, spring, or screen. The right propeller hub was fractured, and two of the three blades remained attached to the hub. The separated blade was recovered. All of the blades' pitch change links were fractured. All three blades were twisted toward low pitch. One blade displayed heavy S-bending, leading edge gouging, and was bent into a U-shape. According to FAA records, the six-seat airplane, serial number T310Q0611, was manufactured by the Cessna Aircraft Company (now Tex