WPR10FA056

Failure of the exhaust band V-clamp during cruise flight, which resulted in an in-flight fire and a subsequent forced landing.

About 15 minutes after takeoff, witnesses observed the airplane make a forced landing adjacent to a railroad track. The airplane touched down partially on the track and bounced several times before coming to rest about 500 yards beyond the initial point of impact. The witnesses reported that the engine was at idle power during the shallow approach. The fuselage and engine area were thermally damaged and the pilot suffered fatal injuries due to a fire. A postaccident examination revealed that a section of the upper left cowling had localized fire damage that was not attributed to the postimpact fire. The left cowling was placed in its normal position just forward of the airplane fuselage. A matching thermal pattern was noted in a small section of the airplane skin just aft of the firewall. Further examination revealed that the left exhaust system transition pipe and V-band clamp had separated from the engine and that the V-band clamp exhibited evidence of corrosion. A metallurgical examination of the V-band clamp revealed that it had fractured through the strap adjacent to a gap between the V-shaped clamping segments. The separation was a result of an overstress fracture of the strap, which was already weakened due to localized oxidation. It is likely that the failure of this clamp resulted in the initiation of an in-flight fire in the engine compartment area.

HISTORY OF FLIGHT On November 14, 2009, about 1615 Pacific standard time, a Beech A36, N17803, collided with terrain during a forced landing near San Gabriel, California. The owner operated the airplane under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. The pilot, the sole occupant, was killed. The airplane was substantially damaged during the accident sequence. Visual meteorological conditions prevailed for the local area flight that departed Brackett Field Airport (POC), La Verne, California, about 1600. The flight was destined for Van Nuys Airport (VNY), Van Nuys, California. No flight plan had been filed. Witnesses reported hearing the engine at idle power, and observing the airplane on a shallow approach to the railroad tracks, with the landing gear down. The witnesses did not report a fire or smoke coming from the airplane when they observed it during the accident sequence. According to a responding detective from the Los Angeles County Sheriff's Department – Aero Bureau, the airplane had touched down on railroad tracks, bounced a couple of times, and came to rest about 500 yards beyond the initial point of impact. A friend of the pilot stated that the purpose of the flight was to move airplanes around. His airplane was at POC, so the accident pilot flew the accident airplane from VNY to Jack Northrop Field/Hawthorne Municipal Airport (HHR), Hawthorne, California. They both flew from HHR to POC to pick up the friend's airplane. The flight from HHR to POC was uneventful. The two pilots departed POC about 1600. The friend arrived back at VNY and awaited the accident pilot. When the accident pilot did not return to VNY, the friend started to call VNY tower personnel, as well as mutual friends, and the business at POC where he had picked up his airplane. The business owner at POC informed him that the news was reporting an airplane crash. PERSONNEL INFORMATION A review of Federal Aviation Administration (FAA) airman records revealed that the 49-year old pilot held a private pilot certificate with ratings for airplane single engine land, single engine sea, and instrument airplane. The pilot held a third-class medical certificate issued on November 10, 2009. It contained the following limitations: the pilot must have available glasses for near vision, and that it was not valid for any class after November 20, 2010. No personal flight records were located for the pilot. The National Transportation Safety Board (NTSB) investigator-in-charge (IIC) obtained the aeronautical experience listed in this report from a review of the FAA airmen medical records on file in the Airman and Medical Records Center located in Oklahoma City, Oklahoma. The pilot reported on his last medical application, dated November 10, 2009, that he had a total time of 850 hours with 0 hours logged in the last 6 months. AIRCRAFT INFORMATION The airplane was a 1977 Beech A36, serial number E-1031. There were no aircraft logbooks available for review. The NTSB IIC obtained copies of aircraft logbook entries for a return to service completed by Howard Aviation, Inc., La Verne, California. The logbook entries were dated November 6, 2009. Airframe total time was listed as 2,255.32 hours. The entries were for the installation of avionics, the installation of circuit breaker switches, and the removal of the number 2 cylinder spark plugs, and the 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 then reinstalled on the cylinder and torqued to specification. The fuel injector was clogged; maintenance personnel cleaned, inspected, and then reinstalled the fuel injector. The airplane was powered by a Lycoming Engines TIO-540-J2BD, serial number L-6400-61A. The engine total time was listed a 2,255.32 hours. WRECKAGE AND IMPACT INFORMATION According to a responding deputy from the Los Angeles County Sheriff's Department Aero Bureau, the first identified point of contact (FIPC) was a ground scar identified adjacent to railroad tracks. The airplane came to rest upright against a concrete wall. Responding 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. 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, Los Angeles, California, completed the autopsy. The cause of death was listed as thermal injuries, rapid; manner of death: accident. The FAA Forensic Toxicology Research Team, Oklahoma City, Oklahoma, performed toxicological testing of specimens of the pilot. Analysis of the specimens contained no findings for carbon monoxide, cyanide, volatiles, and tested drugs. TESTS AND RESEARCH An NTSB investigator, FAA inspector (accident coordinator), and representatives from Hawker Beechcraft and Lycoming Engines examined the airframe and engine at Aircraft Recovery Service, Littlerock, California. For wreckage transportation purposes the left aileron cable, elevator, and rudder cables were cut. Investigators noted that all associated hardware was secured and in place; the cut cables were the 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 tip tank for the right wing had separated. Investigators determined that the landing gear was in the extended position. The instrument panel was consumed by the fire. The fuel selector was determined by investigators to be in the left main tank position; flow continuity was established and a small amount of residual fuel was noted in the associate fuel lines. The airframe manufacturer's representative reported that the flaps were in the retracted setting and the elevator trim was 27 degrees tab down (full deflection), which correlated to nose up trim. There were no identified mechanical anomalies noted 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 airplane fuselage. A matching thermal pattern was noted in a small section of the airplane skin just aft of the firewall. Further examination of the engine 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, and the corresponding portion that remained attached at 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. It states that all V-band couplings and gaskets be replaced at engine overhaul; there were no airworthiness directives that were applicable to the accident V-band clamp. There were no other mechanical anomalies 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, as well as valve train continuity, and the accessory section during manual rotation of the crankshaft. The cylinders were bo