# NTSB WPR19LA125: Stearman A75N1(PT17), N68825, Sequim, WA, April 28, 2019 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: April 28, 2019, 13:37 local (20:37 UTC) - Place: Sequim, WA - Coordinates: 48.047222, -122.874168 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=48.0472&lon=-122.8742&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA - NTSB case key (mKey): 99341 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR19LA125 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99341/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99341 - Page: https://openairdocs.org/ntsb/WPR19LA125 ## Probable cause The total loss of engine power due to the fatigue failure of the crankshaft. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Fatigue/wear/corrosion (probable cause); cases with it: [Boeing A75N1(PT17), 2 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=1380134), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Boeing A75N1(PT17), 2 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=1380134), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Boeing A75N1(PT17), 2 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=1380134), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing-flare/touchdown: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Boeing A75N1(PT17), 22 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1380134), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis 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. ## Factual narrative 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. ## Aircraft - Registration: [N68825](https://openairdocs.org/aircraft/N68825), registered now, S/N 75-5708 (OpenAirDocs) - Reported make and model: Stearman A75N1(PT17) (Undesignat) - Registry model: [Boeing A75N1(PT17)](https://openairdocs.org/model/boeing-a75n1-pt17) (registry code 1380134) (OpenAirDocs) - Registry engine: [Continental W670 series](https://openairdocs.org/engine/continental-w670-series) (registry code 17018, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 75-5708 - Year built: 1942 - Airframe hours: 555.4 - Engines: Continental W670-6A 220 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Port Townsend Aero Museum - Registered owner: Port Townsend Aero Museum - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, August 1, 2018, 5 hours before - Departed: 0S9, Port Townsend, WA - Destination: 0S9, Port Townsend, WA - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 58; injuries: minor; airline transport; airplane ratings: single-engine sea, multi-engine land, single-engine land, multi-engine sea; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review January 31, 2019; seat: rear; restraint: 4-point; flight hours: 20,000 total, 1.1 in this make and model, 19,000 as pilot in command, 225 in the last 90 days, 75 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 10 knots - Observed at: NMI, 20 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20190428003559A](https://openairdocs.org/incident/20190428003559A), Apr 28, 2019: Boeing A75N1(PT17), Port Discovery, WA, Substantial damage. On climbout, the engine began to leak oil as noted by the occupants. PIC turned aircraft around to return to airport. Engine began to shake violently until it… ## Docket (3 files) The files NTSB released with the investigation on December 15, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99341. 10.0 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 3.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12972770&FileExtension=pdf&FileName=Pilot%20accident%20report%20form_Redacted-Rel.pdf - Record of conversation with pilot (item 2, PDF, 2 pages, 93 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12973505&FileExtension=pdf&FileName=Record%20of%20conversation%20with%20pilot-Rel.pdf - Engine examination report (item 3, PDF, 7 pages, 6.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12973626&FileExtension=pdf&FileName=Engine%20examination%20report-Rel.pdf From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.