Everett, WA, USA
N55NH
Yakovlev YAK-55M
The day before the accident, the pilot had asked his mechanic to prepare two other airplanes for flight to a fly-in the following morning. The accident airplane had not flown in a year, nor had there been any entries in the maintenance logbooks in the last four years; it did not have a current condition inspection recorded in the logbooks. The mechanic said that he had been in the process of installing an intake oil drain kit, which drains oil from the lower 3 cylinders from a common quick drain. The mechanic said that the project was not complete, but it had progressed to the point that he had put new oil in the engine. On the morning of the accident, the pilot had to move the airplane out from the back of the hangar and install the engine cowling before flight. He flew to the airport where the fly-in was being held and landed without incident. On his return flight, as he approached the airport, he radioed the tower controller and said that his engine was running rough. Approximately two minutes later, he said that his engine had lost power, and he was going down. A witness on the ground said that he heard a loud bang and looked up to see blue-gray smoke coming from the airplane. Another witness said she saw the airplane making a low left turn, when it flipped inverted and spiraled to the ground. The airplane impacted in a residential area, approximately 15 feet behind a home. A post impact fire consumed the airplane. During an engine teardown, a cylinder was removed and significant heat distress was found on and around the main rod bearing. The main rod bearing was plastically deformed and broken; several connecting rods were bent and/or broken. Additionally, a heavy oil coating was found all along the bottom of the fuselage and most of the empennage was covered with oil. If the pilot had performed an adequate preflight before his return flight, it is likely that he would have noticed a significant loss of engine oil.
HISTORY OF FLIGHT On July 14, 2007, at 1321 Pacific daylight time, a Yakovlev Yak-55M experimental airplane, N55NH, was destroyed when it impacted terrain in Everett, Washington. The private pilot, the sole occupant in the airplane, was killed. The pilot, who was the registered owner, was operating the airplane under Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the personal cross-country flight, which originated from Arlington, Washington, approximately 20 minutes before the accident. The intended destination was Paine Field (PAE), Everett, Washington; no flight plan had been filed. According to a mechanic who was employed full time by the pilot, the pilot owned three airplanes and was building a fourth. The mechanic said that the day before the accident, the pilot requested that he prepare the Cessna T210 and Bellanca Scout for flight. The pilot was planning to take one of these airplanes to a fly-in at Arlington Municipal Airport (AWO), Arlington, Washington, the next day. The mechanic reported that he had not completed the maintenance that was in progress on the accident airplane. In order to fly it, the pilot had to move the airplane out from the back of the hangar, and install the engine cowling. Paine Field Air Traffic Control (ATC) reported that the accident airplane departed at 0930. The pilot flew to Arlington and landed without incident. At approximately 1300, the airplane was photographed departing Arlington Municipal Airport. Approximately 15 minutes later, the pilot radioed Paine Field ATC and said that he was crossing I-5 (Interstate 5) for landing, and his engine was running rough. Approximately two minutes later, he said that his engine had "quit," and he was going down. A witness on the ground said that he heard a loud bang and looked up to see blue-gray smoke coming from the airplane. Another witness said she saw the airplane making a low left turn, when it flipped inverted and spiraled to the ground. A post impact fire consumed the airplane. PERSONNEL INFORMATION The 66-year-old pilot's most recent third class Federal Aviation Administration (FAA) medical certificate was issued on May 9, 2007. On his application for the medical exam, the pilot indicated that he had 2,000 hours of total flight experience, with 20 hours during the last 6 months. No documentation of a flight review was located. AIRCRAFT INFORMATION The airplane was a single engine, propeller-driven, fixed landing gear, single seat, aerobatic airplane, which was manufactured by Yakovlev in 1992. Its maximum takeoff gross weight was 2,149 pounds. It was powered by a Vedeneyev M-14P, radial 9 cylinder, carbureted, supercharged, air cooled engine, which had a maximum takeoff rating of 360 horsepower at sea level. The maintenance logbooks were located and there had been no entries for approximately 4 years. There was no current condition inspection recorded in the logbooks. The pilot's mechanic said that the airplane had not flown in a year. The mechanic was in the process of installing an intake oil drain kit, which drains oil from the lower 3 cylinders from a common quick drain. The mechanic said that the project was not complete, but it had progressed to the point that he had put new oil in the engine. METEOROLOGICAL INFORMATION At 1253, the weather conditions at Paine Field (PAE; elevation 606 feet), Everett, Washington, located 190 degrees for 3 nautical miles from the accident site, were as follows: wind 310 degrees at 7 knots; visibility 10 statue miles; clear of clouds; temperature 73 degrees Fahrenheit; dew point 57 degrees Fahrenheit; altimeter setting 30.02 inches of mercury. WRECKAGE AND IMPACT INFORMATION The airplane impacted in a residential area, approximately 15 feet behind a home (elevation 300 feet). The intense heat generated by the post impact fire melted the siding on the house and charred nearby vegetation. The initial impact point was approximately 10 feet from where the airplane came to rest; the orientation of this path was 090 degrees. According to a witness, the airplane initially came to rest in a nose down attitude with the tail projecting into the air approximately 30 degrees from vertical. During the post impact fire the airplane settled onto its belly, with the fuselage aligned to the south. All of the airplane's major components were accounted for at the accident site. All the flight controls moved slightly, demonstrating control continuity. The instrument panel and cockpit were destroyed from thermal damage. Both wings were in place. The inboard half of the left wing was totally burned forward to the main spar. The right wing exhibited extensive thermal damage. The aft end of the fuselage and the metal portions of the empennage exhibited minimal thermal damage. The elevator and rudder were fabric-covered surfaces and all the fabric was burned. No evidence was found of any pre-impact mechanical discrepancies with the airplane's airframe. On July 25, 2007, a team of investigators met to teardown the engine. A cylinder was removed, which revealed significant heat distress on and around the main rod bearing. The main rod bearing was plastically deformed and broken; several connecting rods were bent and/or broken. Additionally, a heavy oil coating was found all along the bottom of the fuselage and most of the empennage was covered with oil. MEDICAL AND PATHOLOGICAL INFORMATION The Snohomish County Medical Examiner's Office, Everett, Washington, performed an autopsy on the pilot on July 15, 2007. They determined that the cause of death was multiple blunt trauma. The FAA's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, performed toxicology tests on the pilot. According to CAMI's report (#200700158001), his blood was tested for carbon monoxide and cyanide with negative results; his vitreous was tested for ethanol with negative results. The pilot's blood and urine was tested for drugs, and Diphenhydramine was detected.
The pilot's inadequate preflight planning and inspection that led to oil exhaustion and a catastrophic engine failure. Also causal was the pilot's attempted operation of an aircraft with known deficiencies, and the lack of a current airworthiness inspection. Contributing to the accident was the pilot's failure to maintain an adequate airspeed while maneuvering following the engine failure.
Source: NTSB Aviation Accident Database
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