NTSB CAROL · Event
Event WPR23LA215
Aircraft involved
Probable cause & findings
The total loss of engine power due to the fatigue failure of the crankshaft accessory drive gear.
Factual narrative
On June 4, 2023, at 1130 Pacific daylight time, a Piper J-3C-65, N77583, was substantially damaged when it was involved in an accident near Belfair, Washington. The flight instructor and the student pilot were seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor stated that he and the student pilot had been practicing maneuvers before they proceeded toward the Bremerton National Airport (PWT), Bremerton, Washington. The student pilot performed the before-landing checklist, which included checking fuel and turning on carburetor heat, as they were about 2 miles from runway 02. Shortly after, they heard a loud noise followed by a total loss of engine power. The flight instructor took control of the airplane and initiated a forced landing to an open area. During the landing roll, the airplane impacted rough and rising terrain. The left wing partially separated, and landing gear collapsed, which resulted in substantial damage to the fuselage. A postaccident examination of the airframe and engine revealed that, when the propeller was rotated, neither magneto coupling could be heard firing. The right magneto was removed, and remnants of the crankshaft accessory drive gear were observed in the accessory case. No additional, non-impact related anomalies were noted with the engine or airframe. The engine was disassembled, and the crankshaft and the gear remnants were removed and sent to the National Transportation Safety Board Materials Laboratory for further examination. The fracture faces of the gear contained mechanical damage. Two of the fracture faces contained fatigue striations typical of fatigue cracking that emanated from the root of the gear. The fatigue crack in these two gear fragments extended through the entire width of the gear. The terminus of each fatigue crack was not defined because of the severe mechanical damage on the fracture faces. The engine had accumulated about 278 hours since last overhaul and about 20 hours since the last annual inspection. The total number of hours on the engine could not be determined. The flight instructor reported that during an instructional flight, while approaching the airport to land, there was a loud noise followed by a total loss of engine power. The flight instructor took control of the airplane and initiated a forced landing to an open area. During the landing roll, the airplane impacted rough and rising terrain. The left wing was partially separated, and landing gear was collapsed. Postaccident examination of the engine found the crankshaft accessory drive gear had failed. Metallurgical examination of the crankshaft and gear remnants revealed the fracture surfaces of two of the gear teeth had signatures of fatigue. Mechanical damage to the terminus of the observed fatigue cracks prevented determination of the initiating event that resulted in the eventual failure of the gear. The failed gear prevented both magnetos from operating, which resulted in a total loss of engine power due to a lack of ignition. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12
NTSB Findings
Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).
- — Aircraft-Aircraft power plant-Accessory gear-boxes-(general)-Failure
- — Aircraft-Aircraft power plant-Engine (reciprocating)-Recip eng rear section-Failure
- — Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Altitude-Attain/maintain not possible
Verbatim from NTSB's published report. Source file
NTSB_2023_WPR23LA215.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
What the literature says.
Academic papers and agency reports matching this event's aircraft type or causal vocabulary (icing). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- NASA NTRS 2026 · Contractor Report (CR)
Icing Physics Studies Using the 3D SIDRM Test Article: 2023 Icing Tests Analysis
In-flight icing is an important safety issue and is a factor that affects aircraft design and performance. Newer regulations are driving a need for improvements in airframe and engine icing simulation…
- arXiv 2025 · arXiv preprint
Multi-Agent Deep Reinforcement Learning for UAV-Assisted 5G Network Slicing: A Comparative Study of MAPPO, MADDPG, and MADQN
The growing demand for robust, scalable wireless networks in the 5G-and-beyond era has led to the deployment of Unmanned Aerial Vehicles (UAVs) as mobile base stations to enhance coverage in dense urb…
- Embry-Riddle Scholarly Commons 2025 · Journal article (JAAER)
A Mathematical Model on the Temporal Dynamics of Aviation Competitive Pricing
This study investigates the competitive dynamics of airport pricing using U.S. airport data to validate the findings. It employs linear and nonlinear ordinary differential equation models to analyze t…
- NASA NTRS 2025 · Presentation
NASA Icing Update – March 2025
This NASA Icing Update was prepared for presentation to the SAE International AC-9C Inflight Icing Technology Committee. This update includes the following topics: planned Rotational Icing Scaling tes…
- arXiv 2024 · arXiv preprint
An energy-stable phase-field model for droplet icing simulations
A phase-field model for three-phase flows is established by combining the Navier-Stokes (NS) and the energy equations, with the Allen-Cahn (AC) and Cahn-Hilliard (CH) equations and is demonstrated ana…
- NASA NTRS 2024 · Presentation
NASA Icing Update – Oct 2024
This presentation provides a status update on select NASA icing research activities for the SAE AC-9C Icing Technical Committee Meeting on Oct 21, 2024.
Browse the full corpus — academia portal ↗