Dana Point, CA, USA
N546BC
Cessna T210N
The airplane impacted the ocean following a departure from controlled cruise flight. The airplane had decelerated from 120 knots to approximately 60 knots while maintaining an altitude of 3,500 feet mean sea level (msl), then descended as rapidly as 7,000 feet per minute, finally spiraling toward the ocean in a corkscrew manner before it impacted the water. No pre-accident anomalies were noted with any systems examined, and no distress calls or communications preceded or followed the upset. The autopsy report on the 51-year-old airline transport pilot was consistent with a condition known as left ventricular hypertrophy (LVH), a substantially thickened main heart chamber. It also noted moderate to severe coronary artery disease with evidence of at least one prior small heart attack. The combination of coronary artery disease and LVH would have substantially increased the risk for sudden cardiac death in this pilot. There was no evidence that the pilot was aware of his heart disease. The behavior of the aircraft cannot be explained by any reasonable scenario in which the 11,500-hour pilot was deliberately controlling the aircraft. Therefore, it seems likely that the pilot was unable to control the aircraft, an inability that can reasonably be explained by an incapacitating cardiac event.
HISTORY OF FLIGHT On November 19, 2005, at 1403 Pacific standard time, a Cessna T210N, N546BC, impacted the Pacific Ocean and sank about 3 miles south of Dana Point, California, following a departure from controlled cruise flight. T.R. Builder Corp. of Newport Beach, California, operated the airplane under the provisions of 14 CFR Part 91 as a personal flight. The airline transport pilot and his three passengers were fatally injured, and the airplane was destroyed. Visual meteorological conditions prevailed and a flight plan was not filed. The flight departed the Brown Field Municipal Airport in San Diego, California, at 1335 and was destined for the John Wayne Airport in Santa Ana, California. The airplane was not receiving air traffic control services at the time of the accident; however, radar data was obtained from the FAA's Continuous Data Recording (CDR) using the Camp Pendleton Air Surveillance Radar (ASR-9). The flight was utilizing a transponder beacon code of 1200. Using the radar data and wind information provided by the NTSB's weather group, a NTSB vehicle performance specialist conducted an aircraft performance study, which revealed the following information: The airplane was in level, cruise flight at 3,500 feet mean sea level (msl) and at a calculated airspeed of about 120 knots when at 1359:47, the airspeed began to decrease. The airplane maintained an altitude of 3,500 feet as the calculated airspeed decreased. About 1401:19, the calculated airspeed had decreased to approximately 60 knots when the altitude information showed the airplane depart from level flight, reaching a maximum descent rate of about 7,000 feet per minute down to an altitude of 2,000 feet msl. There were no distress calls heard over the local radio frequencies or any reports from the pilot after departing the San Diego area. A witness located on a sailboat approximately 2 miles offshore indicated he looked up and observed an airplane in a nose low attitude spiraling toward the ocean in a corkscrew manner. He believed the airplane was conducting aerobatic maneuvers, but watched for about 10 seconds before realizing it was not going to pull out before impacting the ocean. The airplane impacted the water in the nose low attitude about 100 yards from the boat. The witness and other boat crewmembers boarded a smaller motorized boat and traveled to the impact point. The largest piece of debris located was a door from the cockpit/cabin area. When asked if the airplane was intact as it descended toward the ocean, the witness said he believed it was (mentioning he noticed the tail and the wings). The witness added that he did not hear any engine noise associated with the airplane. PERSONNEL INFORMATION The 51-year-old pilot held an airline transport pilot certificate with single- and multi-engine airplane ratings, and a commercial pilot certificate with single-engine sea and glider ratings. He also held a flight instructor certificate for single-engine, multi-engine, and instrument airplanes. His second-class medical certificate was issued on April 9, 2004, with no limitations. According to the pilot's last medical certificate application he accumulated a total flight time of 11,000 hours. Review of his latest logbook revealed he logged 409.5 hours since the medical certificate, the majority of which were logged in the accident airplane and a Cessna 310. The last flight recorded in the logbook was on June 27, 2005. The pilot's family provided copies of a calendar he used to record flight time before he transferred the time to the logbook. From July 2005, until November 15, 2005, the pilot posted 124.9 hours mostly in the accident airplane. On March 28, 2005, the pilot satisfactorily completed a flight review as per FAR Part 61.56. Friends and family of the pilot provided a 72-hour history of his activities prior to the accident. The information provided indicated that on November 16 at 1630, the pilot arrived at the Orange Coast College to teach ground school. His class lasted from 1800 until 2200. He arrived home at 2230 and went to bed at 2300. On November 17, the pilot awoke at 0600 and left for the John Wayne Airport at 0630. At 1630, he finished work and his last flight for the day. After completing some paperwork he arrived home at 1800 and went to bed at 2230. On the 18th of November, the pilot awoke at 0615 and departed for the John Wayne Airport at 0845. He was to fly the accident airplane to Mexico where he was to monitor off-road races in the San Felipe area of Baja California. He cleared Mexican customs at 1030 and tracked a race between 1145 and 1900. About 1900, the pilot refueled the airplane and continued tracking the race between 1945 and 0030 on the 19th. At 0045 on the 19th, he finished flying in San Felipe and went to bed at an unknown time. At 0900 on the 19th, he began preparing the accident airplane for the return trip to John Wayne. At 1300, he arrived at the U.S. customs facility at the Brown Field Municipal Airport in San Diego, California, and departed at 1335 for the last leg of the flight. According to his family, he did not report any physical problems in the days leading to the accident. AIRCRAFT INFORMATION The accident airplane (serial number 2103663) was equipped with a six-cylinder Continental TSIO-520-R9 engine (serial number 294346-R). Review of the aircraft maintenance records revealed that the airplane underwent its last annual inspection on October 21, 2005, at an airframe and engine total time of 4,801.0 and 642.1 hours, respectively. The total time of the airplane at the time of the accident was 4839.4 hours. The engine underwent a factory rebuild and was zero-timed about 680 hours prior to the accident. The airplane had undergone a number of modifications, one of which included the installation of a Robinson STOL (Short TakeOff and Landing) kit. According to the STOL kit Supplemental Type Certificate (STC) holder, installation of the equipment and modification of the aircraft does not result in a reduction of stall speed. The system is only intended to increase controllability at slower airspeeds. According to the STC holder, the stall speeds remain the same as published in the pilot operating handbook (POH)/information manual. According to the T210N information manual the stall speed at 4,000 pounds, with the most rearward center of gravity, flaps retracted, and power off, is 67 knots calibrated (68 knots indicated). METEOROLOGICAL INFORMATION At 1353, the weather observation facility located at the John Wayne Airport reported the wind as variable at 4 knots, visibility 10 statute miles, with clear skies, temperature 28 degrees Celsius, dew point -03 degrees Celsius, and an altimeter setting of 30.00 inches of mercury. Witnesses reported the weather as clear skies and calm wind in the vicinity of the accident site around the time of the accident. WRECKAGE AND IMPACT INFORMATION Witnesses to the accident marked the location where it impacted water as 33 degrees 24.6 minutes north latitude and 117 degrees 40.9 minutes west longitude. Recovery of the wreckage took place on November 22, 2005. The airplane remained intact via its primary structure and/or control cables. The lower side of the fuselage and engine sustained significant impact damage from the bottom side up and aft. The wings were cut from the fuselage to facilitate transport. The airplane was then taken to Aircraft Recovery Services in Palmdale, California, where it was examined on December 8, 2005, by the NTSB investigator-in-charge, two FAA inspectors from the Long Beach Flight Standards District Office (FSDO), an investigator from Cessna Aircraft Company, and an investigator from Teledyne Continental Motors. The engine remained attached to the firewall, but the left-side engine mounts were fractured and separated. The right-side engine mounts were attached to the engine, but were fractured as well. The engine was intact and the propeller was attached to the propeller flange. The three-bladed propeller exhibited impact damage on two blades, but the third blade appeared undamaged. The spinner exhibited impact damage on half of its circumference, opposite the side of the undamaged blade. The top spark plugs were removed and the propeller was rotated manually. Thumb compression and valve train continuity was confirmed on all six cylinders and crankshaft continuity was confirmed from the propeller aft to the accessory section. Borescope examination of the cylinders and valves revealed no anomalies. The turbocharger remained attached to the exhaust, but the compressor wheel did not initially rotate due to salt-water submersion. After the turbocharger was removed and the turbine wheel was rotated, the compressor wheel was freed and continuity was established by the free and symmetric rotation of the turbine and compressor wheels. Neither the turbocharger compressor nor the turbine displayed axial or radial play at the time of the inspection. The throttle body and fuel control unit remained attached to the engine. The throttle plate was found in the idle position and the throttle lever exhibited impact damage at the cable-attach point. The throttle and mixture levers rotated freely when manually manipulated. The fuel pump was intact, attached to the engine, and the fuel lines visually appeared uncompromised. The fuel pump was removed from the engine and the presence of (100LL) fuel was detected. The drive coupling was intact, undamaged, and exhibited normal operational signatures. The fuel pump was rotated via the engine drive gear and the drive coupling installed. The pump expelled fuel at that time from the engine supply line. The fuel manifold valve was intact and remained attached to the engine. The valve was safety-wired and secured by a lead seal. The safety-wire was cut and the valve was disassembled. The valve body, screen, diaphragm and valve assembly, and main spring did not display any anomalies. The fuel screen was unobstructed and undamaged. With the exception of the cables that were cut to facilitate transport, control continuity was confirmed from the cockpit to the rudder, elevator, elevator trim, and ailerons. The cockpit/cabin floor was crushed and displaced upward and the engine firewall was displaced up and aft. The right rudder pedals were deflected with the right rudder in the forward position. The elevator trim actuator measured 1.4 inches, which according to Cessna, equated to a 7-degree tab down setting. The flap selector handle was in the 10-degree flap setting; however, measurement of the flap actuator revealed 4.1 inches of jackscrew was showing, which equated to a flaps retracted position. The landing gear handle was found in the down position; however, the main landing gear down lock actuators each measured 1.5 inches, which was the equivalent to a landing gear retracted position. In addition, the landing gear down lock hooks were not damaged. Examination of the elevator revealed that the trailing edges of the left and right sides could be rotationally displaced in relation to each other. The maximum displacement measured was a quarter of an inch either side of the neutral position. A hole was drilled into each elevator and a borescope was utilized to examine the rivets that attached the torque tube to the elevators' inboard ribs. The machined head of the rivets were present on the inboard (visual) side of the ribs, but some of the bucked ends of the rivets, located on the outboard (or internal) portion of the ribs, were missing. The forward inboard portions of the left and right elevator airfoils, including torque tubes and control horn, were removed from the larger elevator assembly and were shipped to the NTSB materials laboratory in Washington, D.C., for further examination. The S-Tec Autopilot system was also removed from the wreckage and shipped to the NTSB's South Central Regional (SCR) Office in Arlington, Texas, for further examination/testing at the manufacturer's facility. TESTS AND RESEARCH Elevator Examination The outboard ends of each torque tube were connected to the inboard ribs of each elevator with six solid rivets. The rivets were solid aluminum, 3/16-inch diameter, universal heads, with the bucked heads positioned outboard. Although the elevators could be moved somewhat relative to the torque tubes, they remained firmly attached to each other by heavy gauge sheet metal structure within the torque tubes and elevators. Internal inspection of the elevator airfoils found four fractured rivets on the left side and five fractured on the right side. The rivets were fractured through the shanks and only one of the fractured manufactured head was recovered. Two intact rivets were found on the left side and one on the right side. A second rivet head was found in place on the right side but the shank was fractured. The elevators were removed from the torque tubes after the upset tails of the intact rivets were cut along with the rivets securing the internal structure to the torque tubes. The fractured rivets clearly showed overstress shearing features and deformation consistent with rotation of both elevators about the torque tubes. The indicated directions were as if the trailing edge of each elevator was rotated upward, relative to stationary torque tubes. In addition, the sheet metal holes at the fractured rivets were deformed and elongated consistent with the indicated rotation. The sheet metal around the intact rivets showed scuffing and damage in a more vertical direction and included deformation and cracking. The inboard ends of this structure in both elevators were distorted resulting in twisting along the torque tube axis. The twisting was approximately equal on both sides and in the same directions. The indicated twisting direction was the same for the shearing of the rivets, consistent with upward movement of the elevator trailing edges. When separated, the faying surfaces of the left side elevator were locally darkened with deposits consistent with fretting and small amounts of relative movements between surfaces. In contrast, the right side faying surfaces were relatively clean showing little or no fretting. The faying surfaces on both elevators did show scuffing and abrasions indicative of larger scale relative movements consistent with movements after the rivets were sheared. S-Tec Autopilot Examination The following S-Tec components were examined at the manufacturer's facility in Mineral Wells, Texas on March 28, 2006, under the supervision of an air safety investigator from the NTSB's SCR office: S-Tec 55X Controller PN: 01192-0-11 TF SN: 0502-7784 S-Tec Turn Coordinator PN: 6405-28L SN: 0504-16429G Roll Servo PN: 0106-R9 SN: 0505-19212 CEFGJ Pitch Servo PN: 0108-P4 SN: 0505-14125 CDEFG Trim Servo PN: 0106-T9 SN: 0505-19213 CEFGJ The S-Tec technician first attempted to functionally test the 55X controller unit by applying power; however, the initial readings were not conducive to adding additional power due to the possibility of causing internal damage. The controller was disassembled and corrosion was noted on all boards, the bezel, and respective pins. On the bottom board, which controls the servos, the technician reported that a 33-guage (measured) wire was soldered across the 10-volt fuse, which was not typical to their design. The wire appeared to be in good condition. A resistance reading of 4 to 5 ohms was obtained across the wire. A decision was made to clean the boards and attempt to once again apply power with the 33-guage-wire in place. The technician reported that when the top cover of the unit was removed, it was noted that the S-Tec Inspector Seal, which was placed on the unit prior to shipping, had been breached. This seal was placed on the top cover and is strategically placed over one of the cover attachment screws and down the side of the unit. It appeared that the section of label over the screw had been depressed by a screwdriver and was pushed down into the screw housing. S-Tec personnel opined that the 33-gauge wire would not have contributed to any problems with the autopi
The pilot's inability to maintain aircraft control, which resulted in a loss of airspeed and a stall/spin. The inability of the pilot to maintain control of the airplane was likely due to an incapacitating cardiac event.
Source: NTSB Aviation Accident Database
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