Copemish, MI, USA
N756CS
Cessna TR182
The airplane was destroyed during an on-ground fire following an emergency descent/landing due to an in-flight fire. The pilot reported that he smelled smoke followed by the cabin filling with heavy black smoke. The pilot stated flames began to enter the cockpit as he maneuvered the airplane for a landing in an agricultural field. The airplane nosed over during the landing. The left exhaust stack assembly contained a fatigue fracture adjacent to the main collector welded joint. The fracture was in both the heat affected zone and parent material. The fracture initiated in multiple locations on the outside surface of the tube and progressed through a fatigue mechanism. Energy dispersive spectroscopy (EDS) confirmed that both the weld and tube material met design specifications. The weld profile contained no apparent flaws. The left exhaust stack assembly had accumulated approximately 100 hours since new. The design of the Cessna supplied left exhaust stack assembly differs from the comparable Knisley PMA assembly. The Cessna assembly has a two-piece main collector. The two halves are stamped-out and joined together with a seam weld. The weight of the turbocharger assembly is supported in part by the left exhaust stack assembly. The Knisley main collector is manufactured by welding several tube sections together. Knisley issued a mandatory service bulletin that called for the removal of their left exhaust stack assembly and its replacement with the current Cessna assembly or FAA approved equivalent. The service bulletin states that the replacement was instituted because the Knisely assembly was not designed to carry the load of the turbocharger and compressor.
HISTORY OF FLIGHT On July 27, 2002, at 1230 eastern daylight time, a Cessna TR182, N756CS, piloted by a private pilot, was destroyed during an on-ground fire following an emergency descent and landing due to an in-flight fire near Copemish, Michigan. Visual meteorological conditions prevailed at the time of the accident. The personal flight was operating under the provisions of 14 CFR Part 91 without a flight plan. The pilot and front-seat passenger sustained serious burn injuries. The rear-seat passenger sustained minor injuries. The flight departed from Mason County Airport, Ludington, Michigan, at 1215 and was en route to Cherry Capital Airport, Traverse City, Michigan. According the pilot's written statement, during the accident flight he smelled smoke, which was followed by the cabin filling with a "heavy black smoke". The pilot stated flames began to enter the cockpit as he maneuvered the airplane for a landing in an agricultural field. The pilot reported that he opened the left cockpit window due to the smoke filled cabin and unlatched the cockpit door just prior to landing. The pilot stated that during landing the airplane flipped over. PERSONNEL INFORMATION The pilot held a private pilot certificate with airplane single-engine land, airplane multiengine land, and instrument airplane ratings. The FAA issued the pilot certificate on June 19, 2002. FAA records indicate his last medical examination was completed on April 24, 2002, and that he was issued a third-class medical certificate with limitation "must wear corrective lenses." The pilot had accumulated a total flight time of 753.6 hours, of which 624.5 hours were as pilot-in-command. The pilot reported that 691.8 hours were in single-engine airplanes and 61.8 hours were in multiengine airplanes. He flew 78.3 hours during the previous 3 months, including 47.3 hours in the same make/model as the accident airplane. He had flown 44.1 hours during the prior 30 days and 9.0 hours during the last 24 hours. AIRCRAFT INFORMATION The accident airplane was a 1979 Cessna TR182, serial number R18201041. The Cessna TR182 is a single engine, high-wing airplane. The Cessna TR182 is equipped with a retractable tricycle landing gear, electrically actuated wing flaps, and is powered by a single reciprocating engine. The fuselage and empennage are of an all-metal semimonocoque design. The metal wings are externally braced and have two integral tanks. The airplane was equipped with dual controls and could accommodate four occupants. The accident airplane had a certified maximum takeoff weight of 3,100 lbs. The airplane was issued a Standard Airworthiness Certificate on April 21, 1979, and was certified as a standard category airplane. According to aircraft maintenance logbooks and the owner's pilot logbook, the accident airplane had accumulated a total flight time of 3,394.2 hours since new. The last annual inspection was completed on January 3, 2002, and the airplane had accumulated 88.6 hours since the inspection. According to the aircraft maintenance logbooks, all applicable FAA Airworthiness Directives had been complied with as of the last annual inspection. The engine was a turbocharged 235 horsepower Lycoming O-540-L3C5D, serial number L-21306-40A. The engine had accumulated 194.6 hours since the last overhaul, which was completed on September 29, 2000. The engine was installed on the accident airplane on December 11, 2000, and the last engine inspection was completed on January 3, 2002. The propeller was a two-bladed McCauley B2D34C217/90DHB-8, hub serial number 791777. METEOROLOGICAL INFORMATION A weather observation station, located at the Manistee County Airport (MBL), 21 nautical miles (nm) southwest of the accident site, recorded the weather as: At 1255: Wind 280 degrees true at 12 knots; 10 statute mile visibility; broken clouds at 2,300 above ground level (agl); temperature 28 degrees Celsius; dew point of 21 degrees Celsius; altimeter 29.79 inches of mercury. WRECKAGE AND IMPACT INFORMATION An inspector with the Federal Aviation Administration performed the initial on-scene investigation. Representatives from Cessna Aircraft Company and Textron Lycoming Engines performed an additional on-scene investigation under the direct supervision of the Michigan State Police. The landing gear had collapsed rearward during the landing attempt and the airplane nosed-over after traveling forward approximately 50 feet. The airplane was found resting inverted and the entire cabin area was consumed during the post-accident fire. Both wings remained intact and only the inboard portions were affected by fire. The engine remained attached to the firewall and both were damaged by fire. The turbocharger exhaust waste gate was found fully closed and the carburetor was consumed by fire. The lower right engine cowling was more affected by fire than the lower left side. The fiberglass cabin heat valve body (p/n: 2253006-3) was consumed during the fire. The cabin heat valve door (p/n: 1253067-8) was found open and the torsion spring (p/n: 1253070-1) that normally forces the door shut was found disengaged from the control arm (p/n: 1253069-4). The valve seal (p/n: 1253067-9) that is normally attached to the aft portion of the valve door was consumed during the fire. The steel hinge rod, which is welded to the valve door, remained indexed to the control arm by safety wire. The cabin heat control cable remained attached to the control arm. The cabin heat control cable housing is secured by an aluminum bracket (p/n: 2253008-1) and steel clamp (p/n: S2226-1). The bracket is attached to a firewall stiffener plate (p/n: 0753102-9) by aluminum rivets. The bracket had separated from the stiffener plate and was destroyed by fire. The left exhaust stack assembly (p/n: K2254012-2, s/n: 106419) contained an approximately four-inch fracture around the main collector welded joint. Selections from the Cessna TR182 Illustrated Parts Catalog (IPC) that diagram the cabin heat valve assembly and left exhaust stack assembly are included with the docket material associated with this factual report. TESTS AND RESEARCH According to the TR182 Type Certificate Data Sheet, Cessna Aircraft Company modified the supplied Lycoming O-540-L3C5D engine to include a turbocharger system. The installation of the turbocharger system was completed in accordance with Cessna drawing no. 2250065. According to the Cessna TR182 IPC, the turbocharger installed on the accident airplane (s/n: R18201041) is supported by the engine exhaust system and a brace/support (p/n: 2250110-2) that is attached to the engine. The TR182 Type Certificate Data Sheet and selections from the TR182 IPC that depict the turbocharger installation are included with the docket material associated with this factual report. The left exhaust stack assembly (p/n: K2254012-2, s/n: 106419) was manufactured by Knisley Welding, Inc. (Knisley), Loomis, California. Knisley obtained a Parts Manufacturer Approval (PMA) for the production of the assembly on November 15, 2001. The assembly was listed on Knisley PMA supplement no. 23, which was effective on November 15, 2001. The Parts Exchange, Fort Mill, South Carolina, took an order from Victory Air Service, Ludington, Michigan, for a replacement left exhaust stack assembly on November 29, 2001. Victory Air Service was the maintenance facility where the accident airplane was maintained. The Parts Exchange received the replacement part from Knisley on December 7, 2001, and shipped the assembly to Victory Air Service the same day. Aircraft maintenance logbooks indicated the replacement assembly was installed on the accident airplane on December 14, 2001. At the time of the accident, the replaced exhaust stack assembly had accumulated approximately 100 hours since installation. The PMA supplement, work order documentation, and selections from the airframe maintenance logbook are included with the docket material associated with this factual report. The left exhaust stack assembly (p/n: K2254012-2, s/n: 106419) was delivered to the NTSB investigator-in-charge (IIC) for further examination. The IIC submitted the artifact to Packer Engineering Inc., Naperville, Illinois, for a materials laboratory examination. According to the Materials Laboratory Factual Report, the exhaust stack assembly consisted of a number of tubes and flanges joined together by welding. There was a crack adjacent to a weld joint, which extended over an arc of approximately 120 degrees. The fracture was in both the heat affected zone and parent material. An inspection of the weld revealed, "a weld profile with no apparent flaws." The material containing the fracture and weld was sectioned for further inspection. The report stated the fracture appeared to initiate in multiple locations on the outside surface of the tube and progressed through a fatigue mechanism." The report further stated, "Over most of the crack surface, the fine fracture features were obliterated by exposure to the high temperatures and combustion products of the exhaust gases as well as some rubbing." Energy dispersive spectroscopy (EDS) confirmed that both the weld and tube material meet the specifications for a type 321 stainless steel. The Materials Laboratory Factual Report is included with the docket material associated with this factual report. The design of the Cessna supplied left exhaust stack assembly (p/n: 2254012-2) differs from the comparable Knisley PMA assembly (p/n: K2254012-2). The Cessna assembly has a two-piece main collector. The two halves are stamped-out and joined together with a seam weld. The Knisley main collector is manufactured by welding several tube sections together. A design print for the Knisley left exhaust stack assembly is included with the docket material associated with this factual report. An IPC illustration for the Cessna left exhaust stack assembly is included with the docket material associated with this factual report. ADDITIONAL INFORMATION Subsequent to the accident, Knisley issued mandatory service bulletin no. 002 that called for the removal of their left exhaust stack assembly (p/n: K2254012-2) and its replacement with the current Cessna assembly (p/n: 2254012-4) or FAA approved equivalent. The Cessna p/n 2254012-4 differs from the 2254012-2 model due to a material change from type 321 stainless steel to Inconel. The service bulletin states that the replacement was instituted because the Knisely assembly was not designed to carry the load of the turbocharger and compressor. The retained turbocharger components were returned to a representative of the owner on December 16, 2003. The FAA, Cessna Aircraft Company, and Textron Lycoming Engines were parties to the investigation.
The in-flight engine and cabin fire caused by a fatigue fracture of the left exhaust stack assembly. An additional cause was the part's inadequate design by the aftermarket part manufacturer. A factor to the accident was the soft field in which the emergency landing was made.
Source: NTSB Aviation Accident Database
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