Sequim, WA, USA
N68825
Stearman A75N1(PT17)
Shortly after takeoff for a personal flight, about 1,200 ft mean sea level, the pilot observed spraying oil and light oil smoke and detected the smell of oil coupled with an engine vibration. The pilot decided to make a forced landing. The engine vibration increased, and the engine seized before landing. The forced landing resulted in substantial damage to the right wing and fuselage. Examination of the radial engine revealed a crankshaft failure due to fatigue; beach marks (also known as arrest marks) were observed in the region of the fracture surface. The maintenance records indicated that the last engine overhaul was accomplished about 15 years before the accident. Engine time since major overhaul recorded at the last annual inspection about 9 months before the accident was 143 hours.
On April 28, 2019, about 1337 Pacific daylight time, a Boeing A75N1 biplane, N68825, was substantially damaged when it was involved in an accident near Sequim, Washington. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 local personal flight. According to the pilot’s statement, he had departed from runway 27 at Jefferson County Airport (0S9), Port Townsend, Washington, to the west. About 1,200 ft mean sea level (msl), over Discovery Bay, he began to smell burning oil. He then saw spraying oil and a light oil smoke coupled with engine vibration. A return to the departure airport was not an option, so he turned left toward land and began a slight descent with full power. The pilot stated that the terrain on the shoreline was rugged and the surrounding terrain above the shoreline was densely forested. The pilot attempted to troubleshoot the engine vibration; however, there was no change, and the engine vibrations increased. The pilot stated that the windscreen, his face, and goggles were covered in oil and his forward visibility was greatly reduced. He reduced power to land on the rugged shoreline. As the pilot turned toward the beach, the engine seized, and his rate of descent increased. During the flare to land, the right main landing gear and right wing impacted the water. The airplane came to rest upright on the ground, oriented more than 90° from the direction of landing, and sustained substantial damage to the wing and fuselage. A teardown examination of the engine was performed on May 8, 2019. When the No. 3 cylinder was removed the failed crankshaft was observed. Beach marks (also known as arrest marks), consistent with fatigue failure, were observed in the region of the fracture surface. Maintenance records revealed that the airplane was powered by 220-HP Continental Motors W670-6A radial engine, serial number 16541. The most recent annual inspection was completed August 1, 2018, at a recorded tachometer reading of 555.4 hours; the tachometer reading at the time of the accident was 560 hours. Engine time since major overhaul was 143.2 hours. Maintenance records further revealed that an engine overhaul was performed on April 3, 2004, the engine was completely disassembled. All steel components were magnafluxed and all aluminum parts were zyglow-inspected.
The total loss of engine power due to the fatigue failure of the crankshaft.
Source: NTSB Aviation Accident Database
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