No fatalities

28 Apr 2019: Stearman A75N1(PT17) (N68825) — Port Townsend Aero Museum — Sequim, WA

Sequim, WA, United States

On 28 Apr 2019, a Stearman A75N1(PT17) Undesignat (registration N68825) operated by Port Townsend Aero Museum was involved in an aviation accident near Sequim, WA. No fatalities were reported. Investigators recorded the probable cause as: The total loss of engine power due to the fatigue failure of the crankshaft. This summary draws on records from NTSB; 4 related events involving the same aircraft type or operator are linked below.

SourcesNTSBPrimary reportUpdated 1778583330Data APIEditorial standards

On April 28, 2019, a Boeing A75N1 biplane (N68825) made a forced landing near Sequim, Washington, after the engine failed due to crankshaft fatigue. The pilot sustained minor injuries and the aircraft was substantially damaged.

Accident Details

On April 28, 2019, at approximately 1337 Pacific daylight time, a Boeing A75N1 biplane, registration N68825, was substantially damaged during a forced landing near Sequim, Washington. The pilot, the sole occupant, sustained minor injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a local personal flight.

Pilot Account

According to the pilot, the flight departed from runway 27 at Jefferson County Airport (0S9) in Port Townsend, Washington, heading west. While at about 1,200 ft mean sea level over Discovery Bay, the pilot detected the smell of burning oil, observed oil spraying and light oil smoke, and felt engine vibration. Deciding that returning to the departure airport was not feasible, the pilot turned left toward land and began a slight descent while maintaining full power. The terrain on the shoreline was described as rugged, with densely forested slopes above.

The pilot attempted to troubleshoot the vibration but noted no improvement; instead, the vibrations intensified. Oil covered the windscreen, the pilot's face, and goggles, severely reducing forward visibility. Power was then reduced for a landing on the rugged shoreline. As the airplane turned toward the beach, the engine seized, increasing the rate of descent. During the flare, the right main landing gear and right wing struck the water. The airplane came to rest upright on the ground, oriented more than 90° from the direction of landing, with substantial damage to the wing and fuselage.

Engine Examination

A teardown examination of the engine was conducted on May 8, 2019. Upon removal of the No. 3 cylinder, the failed crankshaft was observed. Beach marks, consistent with fatigue failure, were present on the fracture surface.

Maintenance History

The airplane was powered by a 220-horsepower Continental Motors W670-6A radial engine, serial number 16541. The most recent annual inspection was completed on August 1, 2018, at a recorded tachometer reading of 555.4 hours. The tachometer reading at the time of the accident was 560 hours, and engine time since major overhaul was 143.2 hours. Maintenance records showed that an engine overhaul was performed on April 3, 2004, during which the engine was completely disassembled. All steel components were magnafluxed, and all aluminum parts were zyglow-inspected.

Contributing factors

Fatigue/wear/corrosion