On November 15, 2009, a BEECH A36 (registration N17803) operated by David E. Flotho was involved in an aviation accident near San Gabriel, CA. One person was killed. Investigators recorded the probable cause as: Failure of the exhaust band V-clamp during cruise flight, which resulted in an in-flight fire and a subsequent forced landing. This summary draws on records from NTSB; 12 related events involving the same aircraft type or operator are linked below.
A 1977 Beech A36, N17803, crashed near San Gabriel, California, on November 14, 2009, during a forced landing. The sole pilot was killed, and the aircraft was substantially damaged.
Accident Overview and Flight History On November 14, 2009, at approximately 1615 Pacific standard time, a 1977 Beech A36, registration N17803, collided with terrain near San Gabriel, California, during a forced landing. The aircraft was operated by its owner under 14 Code of Federal Regulations Part 91 for a personal flight. The pilot, who was the sole occupant, was killed, and the airplane sustained substantial damage. Visual meteorological conditions prevailed in the area. The flight departed Brackett Field Airport (POC) in La Verne, California, at about 1600 and was destined for Van Nuys Airport (VNY) in Van Nuys, California. No flight plan had been filed. Witnesses reported hearing the engine at idle power and observed the aircraft on a shallow approach to railroad tracks with the landing gear extended. No fire or smoke was reported from the aircraft during the accident sequence. A detective from the Los Angeles County Sheriff's Department Aero Bureau stated that the airplane touched down on the railroad tracks, bounced several times, and came to rest approximately 500 yards beyond the initial point of impact. A friend of the pilot explained that the purpose of the flight was to move aircraft. The pilot had flown the accident aircraft from VNY to Jack Northrop Field/Hawthorne Municipal Airport (HHR) in Hawthorne, California. Both pilots then flew from HHR to POC to pick up the friend's aircraft, a flight that was uneventful. After departing POC at about 1600, the friend returned to VNY and waited for the accident pilot. When the pilot did not return, the friend contacted VNY tower personnel, mutual friends, and the business at POC, where the owner informed him that news reports were already reporting an airplane crash. ## Personnel Information FAA airman records indicated that the 49-year-old pilot held a private pilot certificate with ratings for airplane single engine land, single engine sea, and instrument airplane. He held a third-class medical certificate issued on November 10, 2009, with a limitation requiring available glasses for near vision. The certificate was not valid for any class after November 20, 2010. No personal flight records were located for the pilot. The NTSB investigator-in-charge obtained the pilot's aeronautical experience from FAA airmen medical records in the Airman and Medical Records Center in Oklahoma City, Oklahoma. On his last medical application, dated November 10, 2009, the pilot reported a total time of 850 hours, with 0 hours logged in the preceding 6 months. ## Aircraft Information The aircraft was a 1977 Beech A36, serial number E-1031. No aircraft logbooks were available for review. The NTSB investigator-in-charge obtained copies of logbook entries for a return to service completed by Howard Aviation, Inc., in La Verne, California, dated November 6, 2009. The airframe total time was listed as 2,255.32 hours. The entries covered the installation of avionics, the installation of circuit breaker switches, and the removal of the number 2 cylinder spark plugs and fuel injector. The circuit breaker switches were replaced to comply with airworthiness directive (AD) 2008-13-17. The spark plugs were cleaned, gapped, tested, and reinstalled on the cylinder and torqued to specification. The fuel injector was clogged; maintenance personnel cleaned, inspected, and reinstalled it. The airplane was powered by a Lycoming Engines TIO-540-J2BD, serial number L-6400-61A, with an engine total time of 2,255.32 hours. ## Wreckage and Impact Information A responding deputy from the Los Angeles County Sheriff's Department Aero Bureau identified the first point of contact as a ground scar adjacent to railroad tracks. The airplane came to rest upright against a concrete wall. FAA inspectors reported that the majority of the fuselage had been consumed by the post-impact fire. The right wing remained in its normal relative position, while the left wing, mid-span, had impacted a light pole. The engine separated at the firewall and came to rest in a parking lot just forward of the concrete wall. The propeller assembly remained attached to the engine at the crankshaft flange. ## Medical and Pathological Information The County of Los Angeles Department of Coroner completed the autopsy. The cause of death was listed as thermal injuries, rapid, and the manner of death was accident. The FAA Forensic Toxicology Research Team in Oklahoma City, Oklahoma, performed toxicological testing of the pilot's specimens. The analysis found no carbon monoxide, cyanide, volatiles, or tested drugs. ## Tests and Research An NTSB investigator, an FAA inspector (accident coordinator), and representatives from Hawker Beechcraft and Lycoming Engines examined the airframe and engine at Aircraft Recovery Service in Littlerock, California. For wreckage transportation, the left aileron cable, elevator, and rudder cables were cut. Investigators noted that all associated hardware was secured and in place, and the cut cables were of appropriate length. The right aileron cable remained attached at the yoke to the wing. The left wing separated at the fuel tank location, and the right wing tip tank had separated. Investigators determined that the landing gear was in the extended position. The instrument panel was consumed by fire. The fuel selector was in the left main tank position; flow continuity was established, and a small amount of residual fuel was noted in the associated fuel lines. The airframe manufacturer's representative reported that the flaps were retracted and the elevator trim was 27 degrees tab down (full deflection), correlating to nose-up trim. No mechanical anomalies were identified during the airframe inspection that would have precluded normal operation. The engine separated from the fuselage but remained attached to the engine mount structure and engine cowl. Visual examination revealed no evidence of pre-impact mechanical malfunction. The upper left side cowling exhibited localized thermal damage. Investigators placed the left cowl in its normal position just forward of the fuselage and noted a matching thermal pattern in a small section of the airplane skin just aft of the firewall. Further examination revealed that the left-hand exhaust system transition pipe was detached and the respective V-band clamp was not in place. Investigators located the pipe and V-band among the recovered wreckage debris. The V-band clamp, part number MVT69183-200, LW-12093-5, had separated at the band and showed evidence of corrosion. The pipe exhibited crush damage on the smoke joint end, while the corresponding portion remaining attached to the engine was undamaged. On May 25, 2006, Lycoming Engines issued Mandatory Service Bulletin 240, Mandatory Parts Replacement at Normal Overhaul and During Repair or Normal Maintenance, stating that all V-band couplings and gaskets be replaced at engine overhaul. No airworthiness directives were applicable to the accident V-band clamp. No other mechanical anomalies were noted with the engine. Manual rotation of the crankshaft via the propeller produced thumb compression in proper firing order. Mechanical continuity was established throughout the rotating group, valve train, and accessory section during manual rotation. The cylinders were borescoped with no evidence of foreign object ingestion, and the valves were intact and undamaged. The three-bladed constant speed Hartzell propeller, serial number B1466U, remained attached at the crankshaft flange. One propeller blade was undamaged, the second had some damage near the tip, and the third was bent slightly aft with diagonal striations near the tip area. The propeller governor remained attached at its mounting point with the pitch control rod securely attached at the control wheel. The pitch control was set near the course setting (low rpm). The fuel system was compromised due to the separation of the engine during the accident sequence. The fuel injection servo was undamaged and secured to its mounting flange. The throttle/mixture controls were secured and attached at their respective control arms of the servo. The throttle was positioned at the idle stop, and the mixture control was beyond the mechanical stop, which the engine representative reported was a result of the engine separation. The fuel injection servo and induction system were free of obstruction. The fuel injection nozzles remained secured at each cylinder, and their respective fuel lines remained attached. The fuel pump remained attached to the engine at its mounting pad, and the fuel lines remained secured at their respective fittings. All spark plugs remained secure at each cylinder, and their respective spark plug leads remained attached. The top spark plugs were removed and examined. According to the Champion Aviation check-a-plug chart AV-27, the electrodes displayed coloration consistent with normal operation. The spark plugs in the number two, four, and six cylinders were oil-soaked, attributed to the engine position at the accident site and storage prior to examination. The ignition harness sustained varying degrees of thermal damage and could not be tested. It remained attached to the single-drive dual magneto and respective spark plug. The magneto remained secured on its mounting pad. Magneto-to-engine timing was established; right was 20 degrees, left was 20 degrees before top dead center of the number 1 cylinder. The engine representative verified that these numbers were within manufacturer's specification. Investigators noted that the magneto had been installed onto the engine 180 degrees opposite of the cap, which disabled the retard points. A witness mark inside the cap where the retard points spring tab had been rubbing was identified. Manual rotation of the magneto produced spark at all plug leads. Two exhaust V-band clamps and a section of exhaust pipe were shipped to the NTSB metallurgical laboratory in Washington, D.C., for further examination. A staff metallurgist reported that one clamp had fractured through the strap area, the second clamp was not compromised, and the exhaust pipe was intact. The T-bolt installed on the fractured clamp measured approximately 1.875 inches in length, while the drawing indicated the bolt should have been 3.0 inches for a -5 clamp. The strap portion of the clamp, adjacent to a gap between V-shaped clamping segments, had fractured. The fracture faces were optically inspected and revealed slant fracturing through the strap consistent with a tensile overstress separation. The staff metallurgist also stated that the fracture intersected areas of thick oxidation partially through the strap.