NTSB Factual Report

HISTORY OF FLIGHT

On August 20, 2008, at 1800 Pacific daylight time, a single-engine SOCATA RALLYE 235E, airplane, N711BZ, collided with a California Highway Patrol (CHP) weigh station building near South County Airport of Santa Clara County (E16), San Martin, California. Silicon Rallye, Inc., operated the airplane under the provisions of 14 Code of Federal Regulations Part 91. The private pilot/owner, the sole occupant, was killed. The airplane was destroyed in the post-impact fire; there were no ground injuries. The airplane departed about 1755 for pattern work.

Several witnesses on both the north and southbound lanes of nearby highway 101 reported no smoke or fluid emanating from the airplane, but that it was "undulating" up and down, and flying at a low altitude before the left wing came up and the airplane turned sharply to the right.

An airborne helicopter pilot landing at South County airport reported hearing the accident pilot transmit a radio call on takeoff. A short time later he heard the accident pilot radio that he was on the base leg. The pilot witness was able to see the airplane at this point, and he continued his landing on the parallel taxiway. He heard the accident pilot call 'final,' and then expected to see the airplane on roll-out to his right. He looked to the right, but did not see the airplane. When he looked back, he saw the smoke coming from the weigh station. The pilot stated that he did not hear any "stress or distress" in the accident pilot's voice during his transmissions.

A co-owner in the accident airplane reported that there had been no history of mechanical problems, and for the past 5 years the airplane had been kept at the Reid-Hillview airport, and that the airplane had been at South County Airport for cosmetic repairs; paint touch up. On the day of the accident, they arrived at the airport, and performed a 45-minute pre-flight inspection. This included checking the flight controls and the fuel for contamination. The owner reported there was enough fuel on board the airplane. The accident pilot attempted to start the airplane. They eventually had to jump start the battery. Prior to departure, the accident pilot stated that he was going to do two touch-and-go takeoffs and landings, and then fly to the Reid-Hillview airport.

The co-owner watched as the airplane taxied to the run-up area where it performed a run-up with no discrepancies. After takeoff, the airplane circled over the airport; on final approach the airplane appeared "rock-solid, stable approach." The owner reported that a helicopter was about 150 to 200 feet ahead and to the left of the accident airplane when the left wing of the accident airplane came up and the airplane "dove into the scale facility." The owner stated that the airplane had plenty of power and there was nothing unusual with the flight other than the sharp right-hand banking turn.

PERSONNEL INFORMATION

A review of Federal Aviation Administration (FAA) airman records revealed that the 60-year-old pilot held a private pilot certificate with airplane single-engine and instrument airplane ratings.

The pilot held a third-class medical certificate issued on October 18, 2007; it had the limitation that the pilot must wear corrective lenses for near and distant vision. At this time, the pilot reported on the medical application 1,000 hours total flight time. No other personal flight records were located for the pilot.

AIRCRAFT INFORMATION

The airplane was a 1977 SOCATA Rallye 235E, serial number 12936. A review of the airplane’s logbook revealed a total airframe time of 1,580.0 hours at the last annual inspection dated March 3, 2008, performed by Magnum Aviation in San Martin. A work order obtained from Magnum Aviation dated June 24, 2008, identified three items with corrective actions, which included an entry for touch-up paint; the cosmetic repairs that the co-owner had indicated as to why the airplane was at South County.

A Textron Lycoming O-540-B4B5, serial number L18598-40A was installed on the airplane. Total time recorded on the engine at the last 100-hour inspection dated March 3, 2008, was 1,580.0 hours, and time since major overhaul was 482.89 hours.

WRECKAGE AND IMPACT INFORMATION

According to the California Highway Patrol, the airplane came to rest in an easterly direction after impacting the west facing wall of the Northbound Gilroy Inspection Facility weigh station. The propeller assembly, engine, and forward portion of the cockpit were destroyed in the post-impact fire. Both wings separated from the airplane and sustained fire damage along with the tail section.

MEDICAL AND PATHOLOGICAL INFORMATION

On August 25, 2008, the Santa Clara County Medical Examiner completed an autopsy on the pilot. The autopsy report noted the presence of marked coronary artery disease, with a “pinpoint lumen” of the proximal right coronary artery and the proximal left anterior descending coronary artery. The report also noted moderate atherosclerosis of the aorta and cholesterolosis of the gallbladder. There were no indications in the autopsy report of any other pre-existing disease.

The FAA Forensic Toxicology Research Team Civil Aeromedical Institute, Oklahoma City, Oklahoma, performed toxicological testing of specimens of the pilot. The report of testing noted only Losartan detected in the blood and urine.

A review of the pilot's FAA airman medical records noted a history of diabetes, well-controlled on metformin; high blood pressure, well-controlled on nifedipine, lisinopril, and losartan; gout, well-controlled on allopurinol; and high cholesterol, treated with atorvastatin. The pilot’s height was noted as 67 inches and weight as 236 pounds on his most recent application for airman medical certificate. The records do not indicate any history of heart disease in the pilot, and there is no record of any screening tests for such disease other than cholesterol testing in 1999.

TESTS AND RESEARCH

The airframe and engine were examined at Plain Parts, Pleasant Grove, California, on November 25, 2008. The airframe and engine were examined with no mechanical anomalies identified. The airframe was mostly consumed in the post impact fire. Investigators were not able to establish flight control continuity due to the thermal destruction of the airplane. Investigators identified the rudder and horizontal stabilizer cables and associated hardware in what remained of the tail section. The cables ends were splayed and broomstrawed. Flight control cables located in the wings, also displayed broomstrawing at the cable ends. The airplane manufacturer identified the seat rails for the two front seats, and noted no discrepancies with the rails.

Investigators placed the engine on a hoist to facilitate the engine inspection. Visual examination of the engine revealed extensive thermal damage, which precluded rotation of the engine. The engine was borescoped with no evidence of foreign ingestion observed. Investigators also noted that there was no evidence of heat distress or lubrication deprivation noted on the connecting rods, crankshaft, and cam lobes. The accessory case was removed; the accessory gears, including the crankshaft gear, bolt, and dowel were intact and undamaged. The magnetos remained attached to their respective mounting pads on the engine. The spark plugs were secured at their respective positions and had sustained thermal damage. The ignition harness appeared to have been attached to each spark plug lead, and had also sustained thermal damage.

The bowl section of the carburetor had been separated, with the fracture surfaces consistent with overload fracture feature. The throttle control was securely attached at the control arm of the carburetor. The fuel pump had been partially consumed by the fire. The fuel pump mounting flange remained attached at its mounting pad, with the safety wire in place and intact.

The propeller assembly remained attached at the engine at the crankshaft flange. The propeller blades showed significant S-bending, leading edge gouging, and chordwise striations, as well as, thermal destruction. It had remained attached at the propeller assembly to the engine.

NTSB Probable Cause

The pilot's incapacitation due to severe unrecognized coronary artery disease that resulted in a loss of aircraft control.