Edgewater, FL, USA
N860MK
Pilatus P3-05
The single-engine experimental airplane was the lead airplane in a formation with three other airplanes, in cruise flight at 1,500 feet above the ground, when it suddenly experienced a catastrophic engine failure and began to veer to the left toward one of the other airplanes. The pilot of the other airplane turned to avoid the accident airplane, and noticed that the accident airplane's cockpit was filling with smoke. Oil was also seen streaming back onto the canopy. The accident pilot requested help, and one of the other pilots attempted to guide him to a safe off-field landing. The accident pilot was then observed to open the cockpit canopy. Smoke and oil were seen pouring onto the pilot's face. The accident airplane then continued to descend until impacting trees and terrain. Examination of the wreckage revealed that the engine's no. 2 connecting rod had separated and punched a hole in the crankcase. A detailed engine exam revealed that the no. 2 connecting rod bearing substrate had delaminated from the steel backing of the bearing, thus allowing excessive bearing clearance. This led to a failure of the rod cap bolts (due to overstress) and separation of the connecting rod from the crankshaft. The separated rod punctured a hole in the engine crankcase, allowing oil to escape and mechanical seizure of the engine. No materials deficiencies of any engine part were noted. The bearing type was the subject of a Lycoming Special Advisory (no. 59-800) in 2000, a Mandatory Service Bulletin (no. 547) in 2001, and another Mandatory Service Bulletin (no. 561) in 2004 which discussed delamination of the bearings for undetermined reasons, and recommended replacement of them with bearings that had "increased durability." These bulletins addressed a higher powered engine (TIO-540), and not the accident engine; however, two other instances of delaminated bearing failures from lower-powered engines (including one similar to the accident engine) were noted. The accident airplane had a propeller installed that was not the one required for normal certification. Additionally, the pilot frequently flew the airplane in formation, thus requiring frequent power changes (with a geared engine). Records indicate that all 6 cylinders were overhauled and sent back to the pilot's mechanic about 6 months before the accident. About 4 months before the accident, the mechanic changed the oil and oil filter about 20 operating hours after the cylinders were replaced. This entry (as well as a previous oil change entry 8 months prior) did not indicate that the oil filters and screens were opened and inspected for metal debris; however, the mechanic stated that he always checked for debris. The airplane had flown an additional 14 flights since the last oil change. The pilot's log indicated that 7 quarts of oil were added to the engine during that time. The final pilot logbook entry was dated one week before the accident and indicated that one quart of oil was added to the engine, at an engine time of 326.2 hours. The logs did not reveal any unresolved discrepancies.
HISTORY OF FLIGHT On April 10, 2004, at 1206 eastern daylight time, an experimental Pilatus P3-05 single-engine airplane, N860MK, registered to and operated by the owner/pilot, was destroyed when it impacted trees during a forced landing near Edgewater, Florida. The certificated private pilot and his passenger were fatally injured. Visual meteorological conditions prevailed, and no flight plan had been filed. The 14 CFR Part 91 personal flight departed from Space Coast Regional Airport (TIX) Titusville, Florida, and was en route to Spruce Creek Airport (7FL6) in Daytona Beach, Florida, at the time of the accident. According to in-flight witnesses, the airplane was flying about 1,500 feet above the ground as the lead airplane in a formation flight of three other single-engine experimental airplanes. The accident airplane began to veer to the left toward one of the other airplanes. The pilot of the other airplane turned to avoid the accident airplane, and noticed that the accident airplane's cockpit was filling with smoke. Oil was also seen streaming back onto the canopy and sides of the fuselage of the accident airplane. The accident pilot requested help, and one of the airplanes attempted to guide the accident pilot to a safe off-field landing. The accident pilot was then observed to open the cockpit canopy. A significant amount of smoke and oil was seen exiting the airplane and pouring onto the pilot's face. Despite repeated attempts to communicate with the pilot via radio, he did not respond. The airplane then impacted trees and terrain. According to a Federal Aviation Administration (FAA) inspector, a large, flat, unobstructed field was located about 1/4 mile west of the accident site. The accident occurred during daylight conditions and was located at 29 degrees 4.81 minutes north, and 81 degrees 2.80 minutes west. AIRCRAFT INFORMATION The accident, a Pilatus P3-05 single-engine airplane, was manufactured in 1959 with serial number 498-47. It was originally designed and built as a Swiss military trainer. The airplane seated two persons in a tandem configuration, had a maximum gross weight of 3,472 pounds, and a wingspan of 34 feet. According to a statement posted by the accident owner/pilot on February 3, 2003, on the Pilatus P-3 Owners Group internet web site, the pilot of N860MK stated that he had "about 20 months and 150 hours experience with this highly modified P-3." The web site also indicated that the Pilatus P-3 series of airplanes are mostly certified under the FAA's provision for experimental-exhibition aircraft, and that about fifty of them are flying in the United States. The airplane was equipped with a Lycoming IGO-480-X fuel-injected, 300 horsepower, six-cylinder, geared, reciprocating engine, serial number BPA-7518. According to Lycoming, the engine was originally manufactured for the military in 1966 as a model O-480-3A, serial no. L-1406-44. The IGSO-480-A1A3 is the equivalent engine in the civilian version. The aircraft was also equipped with a three-bladed Hartzell propeller, which was not the propeller type that the airplane was originally certified with. A review of the engine and aircraft maintenance records, and interviews with engine overhaul technicians, revealed that the engine was purchased as military surplus equipment about 15 years prior to the accident. It was then sent to Barrett Performance Aircraft (BPA) Inc., Tulsa, Oklahoma, for a complete overhaul in September 1999. It was installed on the accident airplane at that time, and then sold to the accident pilot in May 2001 after it had accumulated 25.7 hours of total flight time. Maintenance and pilot records indicated that the airplane received its last condition inspection on July 1, 2003, with a total of 271.5 hours of accumulated engine operating time. No discrepancies were noted. Two months later, on August 27, 2003, all six cylinder assemblies were removed and sent for overhaul at the request of the owner/pilot, because he felt that the oil consumption was excessive. The cylinders were overhauled by BPA and sent back to the mechanic. On October 15, 2003, the cylinders were reinstalled on the engine by the mechanic. The mechanic who maintained the airplane for the pilot was interviewed by the Safety Board. The mechanic verified that all six cylinder assemblies were removed and sent for overhaul at the request of the pilot, because the pilot believed that the oil consumption was excessive. The mechanic stated that there was "abnormally high leak down past the rings," and that there was "excess carbon on the spark plugs." He also recalled that oil usage was high. As a result, the pilot contacted BPA Inc., who had overhauled the engine previously, and BPA Inc. offered to rework the cylinders. The cylinders were overhauled by BPA and sent back to the pilot's mechanic. The maintenance records also revealed that the pilot's mechanic, on December 10, 2003, changed the oil and oil filter about 20 operating hours after the cylinders were replaced. This entry, as well as a previous oil change entry on May 19, 2003 by the same mechanic, did not indicate that the filters were opened for an examination of any metal debris. According to the mechanic, in December 2003, he changed the oil and oil filter about 20 operating hours after the cylinders were replaced, which he stated was standard practice When asked if he had cut open the oil filter to check for metal, the mechanic stated: "Absolutely. To me it's essential. I always cut open the filter, look at the suction screen, if appropriate, and drain the oil in a 15-micron filter into a catch can." He stated that he does this on every oil change that he performs, and that he is very meticulous about it. When asked why the log book entries for the most recent oil change, and that of the previous oil change in May, did not indicate that the filters were opened for an examination of any metal debris, he stated that "we may have missed that," but that he was sure it had been done. The airplane had flown an additional 14 flights, for a total of about 15 hours, since the last oil change. The pilot's log indicated that 7 quarts of oil were added to the engine during that time. The final pilot logbook entry was dated April 3, 2004, one week before the accident, and indicated that one quart of oil was added to the engine, at a total engine operating time of 326.2 hours. The logs did not reveal any unresolved discrepancies. The airplane had logged a total of about 3,570 total flight hours at the time of the accident, and the engine had accumulated about 330 total hours of operation since it was overhauled, and about 36 hours since the cylinders were replaced. Entries in the pilot's logbook did not indicate any aerobatic flights during the two years previous to the accident. Most of the entries indicated local flights or short cross country flights within the state of Florida. The mechanic who maintained the airplane stated that the engine was highly modified, and that the propeller installed on the airplane was not the type in which the airplane was originally certified. He stated that this "non-standard propeller" may have altered the "harmonics" of the engine, and that "harmonics play a vital role" in the engine, especially with a geared engine. The mechanic also mentioned that he, and others, recommended to the pilot to not fly the airplane in formation, because formation flying (which the mechanic has pilot experience with) can involve "relatively aggressive power changes, which is tough on a reduction geared engine." in order to maintain a position in the formation. He stated that formation flying involves "almost continuous power changes" and that engines are not tolerant to "reverse torque flow" such as a windmilling propeller, and can "set up movements" and "unchecked harmonics in the engine." He stated that this, in turn, can create unwanted stresses in the engine. PERSONNEL INFORMATION The pilot held an FAA private pilot certificate with ratings for airplane single engine land and instrument airplanes. The pilot certificate had a limitation that stated that it "was issued on the basis of and valid only when accompanied by Bahamas pilot license 724." According to FAA records, the pilot was issued an FAA third class medical certificate on November 21, 2002, with the limitation that he "must have available glasses for near vision." An examination of a copy of the pilot's logbook revealed that the pilot had logged about 1,800 total hours of total flight experience, including about 275 hours in the accident airplane. Logbook entries indicate that the pilot had flown the accident airplane on 14 flights, for a total of about 15 hours, during a 120-day period leading up the day of the accident. The pilot's mechanic, who had performed the previous two condition inspections, oil and oil filter changes, and cylinder installation, was issued an FAA mechanic certificate with ratings for airframe and powerplant on March 22, 1990. He also held a private pilot certificate with ratings for airplane multiengine land, single engine land, and single engine sea airplanes. METEOROLOGICAL INFORMATION According to a recorded surface weather observation taken about 10 miles north of the accident, and about six minutes before the accident, the lowest sky condition consisted of scattered clouds at 5,500 feet above mean sea level. Visibility was reported at 10 statute miles, with winds at 8 knots from 050 degrees magnetic. The temperature was recorded as 79 degrees F, with a dew point of 60 degrees F. WRECKAGE AND IMPACT INFORMATION The airplane wreckage was examined at the accident site on the day of the accident by an FAA aviation safety inspector. According to the inspector, the airplane impacted a wooded area near a house. A wreckage distribution path was defined by broken tree branches and strewn aircraft parts. The path led to the final resting site of the fuselage. The wreckage distribution path was oriented along a northerly heading. No evidence of an in-flight structural failure was noted. Initial examination of the wreckage by the FAA inspector revealed that the airplane was inverted with both wings sheered off from impact with trees. Oil was found on the canopy pieces and along both sides of the fuselage. The landing gear was found in the extended position, and fuel was leaking from the airplane. The emergency locator transmitter was activated during the crash sequence. After both occupants were removed by fire and rescue personnel, the wreckage was moved to, and secured at, the Volusia County Sheriff's impound lot in Deland, Florida. Three days after the accident, on April 13, 2004, the wreckage was examined at the impound lot again by FAA inspectors and an air safety investigator from the Lycoming engine company. The examination revealed that the engine had a hole, about the size of "two fists placed together," at the top portion of the engine crankcase near the no. 2 cylinder. The no. 2 connecting rod was found broken, and a hole was found in the engine cowling near the area of the no. 2 cylinder. Several quarts of oil were found splattered over the engine, cowling and front portion of the airplane. The wreckage was then moved to an aircraft salvage facility in Groveland, Florida, and examined by the Safety Board on July 9, 2004. The engine was subsequently removed from the airframe and shipped to the Lycoming engine factory in Williamsport, Pennsylvania, to undergo a detailed disassembly and inspection by the Safety Board. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot by the Volusia and Seminole Counties' Office of the Medical Examiner. A toxicological analysis was performed on specimens taken from the pilot by the FAA Civil Aeromedical Institute, Oklahoma City, Oklahoma. TESTING AND RESEARCH Engine Disassembly and Inspection. The engine and its associated accessories were disassembled and inspected by the Safety Board and its investigative participants on August 20, 2004. The propeller governor oil line was found to be properly secured. All fuel flow injector nozzles were removed, and all were found to be open. The crankshaft and camshaft could be rotated only about three-quarters of a revolution. The engine was not seized but was inhibited from further rotation due to a piece of debris inside the engine. The oil filter, a fitting assembly containing the oil temperature probe and a suction screen, a damaged no. 2 cylinder rod cap, and portions of a rod bearing shell exhibited significant extrusion. The rod cap was bent outward and contained one end of a failed rod bolt with the nut still engaged. The rod bolt remnant exhibited evidence of overstress, and did not exhibit evidence of fatigue. The bolt bosses in the rod cap were found intact. The spark plugs were removed for observation and no anomalies were noted. All were removed without difficulty and were undamaged. The nos. 1, 3, 4, 5, and 6 cylinder base nuts were checked for torque including the thru-bolts; they were found to be near or at proper specified torque values. The no. 2 cylinder base nuts were too damaged to be checked. The cylinders were then removed for inspection. Their hold-down plates appeared to be properly installed. Examination of all piston rings, except for the no. 2 piston rings, revealed that the top C-ring had full-face contact. The C-ring on the no. 2 piston had about 50 percent contact. The oil rings were all found to be fully seated. Combustion deposits were noted on all of the piston faces. The deposits were charcoal-colored with very little carbon accumulation. No signs of detonation were evident. All piston skirts were heavily scored with vertical scratches on both thrust and anti-thrust faces. There were no broken rings or damaged piston pins. The pistons were non-PMA parts and were listed on the overhaul parts list by part number. The magneto timing was verified at the proper setting, and both magnetos were functionally checked with no problems noted. The nose case containing the planetary reduction gear was removed intact. An external examination did not reveal any mechanical malfunctions. The nose case gear assembly could be freely rotated without any binding. The accessory case and drive gears were removed intact, and no mechanical deficiencies were noted. The oil pump was rotated and was able to pump oil. The oil pump was accessed and displayed damage consistent with debris being pumped through the engine. The filter contained metallic debris, and the suction screen also contained metallic debris. The engine's internal timing was verified to be correct. The oil sump was removed and contained significant amounts of metallic debris, most of which was identified as bearing material including pieces of steel shell. Also, the steel shell from one of the bearing halves was recovered largely intact; however, it was heavily deformed and was missing pieces of its soft bearing substrate. The steel shell was measured to be nominally .020-inch thick. The mostly intact shell, and shell pieces, exhibited severe extrusion to the point that the radii from crankpin journals formed a similar radius on the extruded shell, consistent with excessive bearing clearance. Some pieces of the shell exhibited severe heat damage and were blue in color. Some of the shell remnants appeared to have been peeled away. The oil pump body exhibited debris damage in the impeller cavities and the impellers. The crankcase was separated and examined for fretting, bearing rotation, and oil passage blockage. All bearing oil holes and crankcase oil passages were found to be clear. The oil holes in the bearings were all aligned with oil supply holes in the crankcase. Cam lobes and tappets exhibited normal wear patterns with no damage present. The camshaft contained some impact marks in the bay where the rod failure had occurred; however the bays contained no impact marks or other damage. Slight tang marks were evident where the main bearings were found be pressed to the crankcase; however, little evidence of fretting w
The delamination of the no. 2 connecting rod bearing for undetermined reasons, resulting in a total loss of engine power. A factor in the accident was the pilot's inability to complete a successful forced landing due to oil on the windscreen, and smoke and oil in the cockpit as a result of the mechanical failure of the engine.
Source: NTSB Aviation Accident Database
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