Aviation Accident Summaries

Aviation Accident Summary MIA97FA242

CORAL SPRINGS, FL, USA

Aircraft #1

N6417Q

Mooney M20F

Analysis

The passenger who is a A&P mechanic stated that about 5-10 minutes after takeoff while climbing through 1,000 to 1,500 feet on a northerly heading with the landing gear retracted, he first noted that the oil pressure dropped to zero then returned to the green arc. The airplane was at that time abeam the point where the airplane eventually crashed. The pilot noted this and began orbiting the area. He then heard a loud sound from the engine and while descending with the landing gear extended, the airplane descended into a man-made pond right wing low. The airplane then cartwheeled and sank in about 17-20 feet of water. The passenger exited the airplane out the main cabin door but the pilot did not escape. He was rescued about 12 minutes later but died in a hospital days after the accident. The airplane was recovered and examination of the engine revealed that the No. 3 cylinder connecting rod and piston pin end plugs failed due to fatigue. Also, a particle was found in the oil passage way of the crankshaft for the No. 1 crankpin. The engine was last inspected in accordance with a 100-hour inspection about 39 hours, and 2 months and 10 days earlier. The engine was a factory new engine that was installed on July 21, 1993 in accordance with a Supplemental Type Certificate. Requests were made following the accident to examine the maintenance records; they were not provided. Copies of the maintenance records were first provided to the National Transportation Safety Board 1 year and 11 months after the accident, by the engine manufacturer. The engine manufacturer obtained copies of the maintenance records from an attorney related to the case. The Nos. 3 and 1 cylinder pistons were installed in the opposite cylinders.

Factual Information

HISTORY OF FLIGHT On September 11, 1997, about 0801 eastern daylight time, a Mooney M20F, N6417Q, registered to B J Aviation, Inc., crashed into a pond near Coral Springs, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 91 business flight. The airplane was substantially damaged and the commercial-rated pilot and an unrestrained dog were fatally injured. The passenger sustained serious injuries. The flight originated about 0752 from the Ft. Lauderdale Executive Airport, Ft. Lauderdale, Florida. According to the passenger, about 5-10 minutes after takeoff while climbing on a northerly heading through 1,000-1,500 feet with the landing gear retracted, he first observed that the oil pressure dropped to zero momentarily then returned to the normal green arc range. He inquired to the pilot about landing on the Sawgrass Expressway, but the pilot elected not to land there due to the amount of traffic. The pilot began orbiting the area, during which, he then heard a loud sound. The pilot then initiated a descent for a forced landing to an open field. With the landing gear extended and the flaps positioned to the takeoff range, while in a nose and right wing-low attitude, the right wing collided with water in a pond about 10 yards from the water's edge. The airplane then cartwheeled to the right and began sinking. The passenger exited the airplane out the cabin entry door, but the pilot did not escape. The passenger further stated that at the time he first noticed the drop in oil pressure, he thought the airplane was abeam the point where the airplane eventually crashed. He also stated that the propeller did not stop rotating. According to a witness near the crash site, he reported seeing the airplane flying northbound, then heard the engine quit followed by a stream of white smoke. The airplane then turned to the east and while descending, a "puff" of dark smoke was noted. The airplane circled to the south and he then lost sight of the airplane due to obstructions. Another witness saw smoke trailing the airplane then the airplane flew over his location which was reportedly about 1/4 mile north of the crash site. He heard a "popping" noise and observed the airplane turn to the west then to the north, as if to land in the field. He noted that the airplane was descending quickly and saw water splash into the air. He did not actually witness the airplane impact the water. PERSONNEL INFORMATION Review of the FAA records revealed that the pilot was a certificated airframe and powerplant mechanic. Further information pertaining to the pilot is contained on page 3 of the Factual Report-Aviation. The passenger is not pilot-rated but is a FAA certificated airframe and powerplant mechanic. AIRCRAFT INFORMATION On July 21, 1993, a factory new Lycoming IO-360-A3B6 engine was installed in the airplane. The recorded tachometer time at that time indicated 2731.52. The engine was installed in accordance with Supplemental Type Certificate SA250GL, which did not require the previous rpm restriction between 2,100 and 2,350; the maximum rpm restriction remained the same. The tachometer indicated post accident, 3,440.65. The airplane was last inspected in accordance with an annual inspection which was signed off on July 1, 1997, according to the mechanic who performed the inspection. He stated that he used Appendix D of 14 CFR Part 43 as a reference and was assisted by the pilot who did the 100-hour inspection. The mechanic with inspection authorization (IA) stated that he did not remove the oil suction screen, that the pilot may have, and that the oil filter was changed. He did not cut open the filter and didn't know if the pilot did. Review of Appendix D revealed in part that there is a requirement to check the oil screens and metal drain plugs for metal particles or foreign matter. Review of recovered paperwork revealed that the oil and oil filter were changed on June 30, 1997, at a tachometer time of 3,401.2 hours and the next oil change was due at 3,451 hours. Requests were made to the co-owner of the airplane and the insurance adjuster following the accident to examine the maintenance records; they were not provided. Copies of the aircraft and engine maintenance records were first made available to the National Transportation Safety Board on August 27, 1999, by the engine manufacturer. According to personnel from the engine manufacturer, they obtained copies of the maintenance records from an attorney related to this case. A letter from a consultant to the engine manufacturer and copies of the maintenance records are attachments to this report. The airplane was registered with the Federal Aviation Administration (FAA) in the name of B J Aviation, Inc., on February 21, 1997. The pilot was one of two owners of the airplane. According to the previous owner of the airplane, who bought it in late 1979, a factory new engine was installed in 1981, and another factory new engine was installed in 1993. The engine installed in 1981 was replaced due to being at the engine manufacturers time between overhaul limit. The previous owner also stated that while he owned the airplane, he had no problems/discrepancies with the engine that was installed in 1993. The oil consumption was reported to be "low." Additional information pertaining to the airplane is contained on page 2 of the Factual Report-Aviation. METEOROLOGICAL INFORMATION Visual meteorological conditions prevailed in the area at the time of the accident. Additional meteorological information is contained on page 4 of the Factual Report-Aviation. COMMUNICATIONS The pilot was in contact with the Fort Lauderdale Executive Airport Air Traffic Control Tower (ATCT) and a transcript of communications is an attachment to this report. WRECKAGE AND IMPACT INFORMATION Examination of the accident site revealed that the airplane crashed into a pond that was about 17-20 feet deep, located near a residential area. The airplane was submerged and a buoy that had been tied to the airplane was observed to be floating about 10 yards south of the north shoreline. According to the diver who helped recover the airplane, it was upright and facing due south while submerged. Examination of the area surrounding the accident site revealed an open, rough field about 2/3 square mile with a mound of trees located slightly less than 1/3 mile north of the northern edge of the pond. The field extended about 200 feet east, from the eastern edge of the pond and about 600 feet west, from the western edge of the pond. About 100 feet south of the southern edge of the pond was a mound of trees. Additionally, an east-west oriented expressway was located about 1/3 mile north from the northern edge of the pond. The airplane was recovered for further examination. Examination of the airplane revealed that the main and nose landing gears were failed aft due to overload with the landing gear selector handle in the down and locked position. The flaps were positioned to the takeoff range. Examination of the flight controls revealed no evidence of preimpact failure or malfunction. The left side of the fuselage just aft of the firewall and the engine rear baffling exhibited evidence of oil clinging to the skin. The lower engine cowling was coated with oil and an oil film was coating the lower firewall. The engine was attached to the airframe and the propeller was attached to the engine. Visual examination of the propeller revealed slight spanwise scratches on one of the two propeller blades. Visual examination of the engine revealed a hole in the top portion of the crankcase between the Nos. 2 and 4 cylinders. The oil dipstick and oil filter were in place and tightly secured, with the oil filter being safety wired. Also, all flexible oil hoses were in place and tightly secured with no evidence of rupture. The stainless steel oil line to the propeller governor was also in place, tightly secured, and intact. The engine and propeller were removed for further examination. During the initial visual examination of the engine and propeller, yellow discoloration of steel and or cadmium plated hardware and fittings was noted. The discoloration was due to the water submersion. Examination of the engine revealed about 1 quart of oil remained inside the engine. Ferrous metal was observed inside the oil suction screen and inside the oil filter assembly. All cylinders were removed and the No. 3 cylinder piston as stamped was found in the No. 1 cylinder position. The No. 1 cylinder piston as stamped was found in the No. 3 cylinder position. Additionally, the No. 3 cylinder connecting rod was observed to be failed. Scoring was noted on all piston skirts of all cylinders and of the cylinder wall at the No.3 cylinder. The piston pin plugs for the No. 3 cylinder were also failed. Examination of the piston dome of the No. 3 cylinder piston revealed that it was nearly void of carbon deposits, lighter in color than the other piston domes, and valve to dome contact was noted. The outer portion of the dome was rounded. Additionally, examination of the dome of the No. 3 cylinder piston and the upper inside portion of the cylinder revealed piston dome-to-cylinder contact. Examination of the piston dome and piston rings for the No. 3 cylinder revealed no evidence of erosion. Additionally, the electrodes for the spark plugs for the No. 3 cylinder were not damaged. Examination of the spark plugs for all cylinders revealed that the plugs for cylinder Nos. 1, 2, and 4, were dark in color and the plugs for the No. 3 cylinder were light tan in color. Examination of the oil pump housing revealed scoring, but the gears were intact. A section of the failed connecting rod cap from the No. 3 cylinder was located between the cabin heat muffler shroud and the muffler; however, portions of the failed No. 3 cylinder connecting rod and cap were not located. The crankcase halves were separated and no fretting was observed at the bearing saddle areas. Also, the oil galleys of the crankcase were examined and the passage ways were free of obstructions. The crankshaft exhibited blueing at the No. 3 cylinder crankpin journal. Scoring was noted at the No. 1 cylinder crankpin journal and a particle was found at the opening of the No. 1 cylinder crankpin oil passageway, adjacent to the connecting rod bearing contact area. The particle which was easily removed and was the shape of the oil passageway hole, was retained for further examination (See the Tests and Research section of this report). Examination of the connecting rod bearing for the No. 1 cylinder revealed extrusion of it. The No. 3 cylinder connecting rod bearing was not in place. Examination of the camshaft which was not failed revealed no evidence of overheating. All gears in the accessory section were in place and the magnetos were tight against the accessory case. No determination was made as to the magneto-to-engine timing. The connecting rod bearings for the Nos. 2 and 4 cylinders were retained for further examination which revealed that the layers were manufactured to specification pertaining to depth and composition. The tin-lead layer of the No. 2 was worn and no evidence of cracks on the surface or disbonding were noted on either bearing. A copy of the metallurgy report is an attachment to this report. The fuel injector servo, flow divider, and fuel injection lines were bench tested with no discrepancies noted. The inlet screen at the fuel injector servo exhibited slight evidence of contamination. During disassembly of the engine, all fuel injector nozzle insets were in place and the nozzles with inserts from Nos. 1 and 4 cylinders were bench tested with no discrepancies noted. The insert from the No. 3 cylinder was not located during subsequent testing. Visual examination of the insert from the No. 2 cylinder revealed no evidence of blockage. The oil cooler with attached hoses was hydrostatically tested to 150 psi and timed for 5 minutes with no decrease in pressure noted. The propeller and propeller governor were disassembled and disassembled for cleaning then bench tested, respectively, with no evidence of preimpact failure or malfunction. MEDICAL AND PATHOLOGIAL The postmortem examination of the pilot was performed by Dr. Lisa Flannagan, Associate Medical Examiner, Broward County Medical Examiner's Office. The cause of death was listed as anoxic encephalopathy. Toxicological analysis of specimens of the pilot was performed by the FAA Toxicology and Accident Research Laboratory and the Broward County Medical Examiner's Office. The results of analysis by the FAA was positive for lidocaine which was detected in the blood and urine. The results were negative for carbon monoxide, cyanide, volatiles, and tested drugs. The results of analysis by the Broward Medical Examiner's Office was positive for lidocaine in the blood and urine. The results were negative for cannabinoids, ethanol, and carbon monoxide. The pilot had received several medications while hospitalized. SURVIVAL ASPECTS The airplane sank in about 20 feet of water and the pilot was rescued about 12 minutes later, revived, then died in a hospital 3 days later. Examination of the cockpit revealed no evidence of appreciable deformation of the occupiable space. The main cabin entry door was observed to be open when the airplane was recovered. The pilot's body was found out of his seat with the seat belt unfastened; the shoulder harness was not secured to the lapbelt. The passenger reportedly braced for impact by placing his left hand on the pilot's seatback and at impact with the water, the unrestrained dog contacted his arm causing his left wrist to break. TESTS AND RESEARCH Metallurgical examination of the failed piston pin plugs, and connecting rod and rod cap from the No. 3 cylinder by the NTSB Materials Laboratory in Washington, DC, revealed fatigue at all components. The inside diameter of the bushing for the piston pin for the failed connecting rod was at only an isolated area, .0004 inch greater than specified in the engineering drawing. A sample piece of the crankcase was retained for metallurgical examination and comparison with the particle found in the oil feed hole for the No. 1 crankpin. Energy Dispersive X-Ray (EDS) examination of the particle and the crankcase sample piece was accomplished on four separate occasions, and five times respectively, by the NTSB Materials Laboratory, to determine chemical composition. The results of both are an attachment to this report. By design, the end plug is composed in part of .2-.8 percent by weight, silicon. According to the American Society for Metals Desk Edition, the connecting rods are comprised in part of .15-.30 percent by weight, silicon. The silicon content of the aluminum alloy layer of the connecting rod bearings was determined to be 2.39 percent. Examination of the lubrication schematic revealed that the oil flows from the oil sump through the suction screen and engine driven oil pump to the oil cooler under normal operating temperatures. The oil then flows through the oil filter to the oil relief valve, then to the right crankcase header to in part, the No. 1 main bearing. The oil then flows through a passageway in the crankshaft to the No. 1 cylinder crankpin where the connecting rod is attached. The oil pressure line fitting on the engine is located between the oil filter and the oil pressure relief valve. ADDITIONAL INFORMATION The wreckage, minus the retained engine was released to Mr. Gene Sheil of Marco Flite Services, Inc., on September 12, 1997. The engine, minus the retained components from the Nos. 1 and 3 cylinders and the particle was also released to Mr. Gene Sheil on December 11, 1997. The retained components from the Nos. 1 and 3 cylinders and the particle were released to Mr. Craig Walker of Marco Flite Services, Inc., on March 9, 1998. The retained connecting rod bearings for the Nos. 2 and 4 cylinders were also released to Mr. Craig T. Walk

Probable Cause and Findings

The pilot's misjudging the distance vs. altitude resulting in the collision with the water short of the intended touchdown point of the rough field. Contributing to the accident was the total loss of engine power due to failure of the No. 3 cylinder connecting rod bearing for undetermined reasons and fatigue failure of the No. 3 cylinder connecting rod and piston pin end plugs.

 

Source: NTSB Aviation Accident Database

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