ANC23LA053
2023-07-12 · Ninilchik, Alaska, United States · None · 1 aircraft · Status: Completed
Airport PASX
Current FAA registration · N83391
- Make / Model
- AERONCA 7DC
- Year of manufacture
- 1946 · 77 years old at event
- Engine
- CONT MOTOR C85 SERIES (85 hp)
- Seats / Engines
- 2 seats · 1 engine
- Last airworthiness date
- 19560527
- ADS-B equipped
- Yes — Mode-S AB672C
Source: FAA Aircraft Registry (releasable master file).
Aircraft involved
Probable cause & findings
A total loss of engine power due to a shift of a crankshaft main bearing, which resulted in a lack of lubrication and subsequent overheating and failure of the engine crankshaft.
Factual narrative
On July 12, 2023, about 1620 Alaska daylight time, a Aeronca 7DC airplane, N83391 sustained substantial damage when it was involved in an accident near Ninilchik, Alaska. The pilot and passenger were not injured. The airplane was operated by the pilot as a Title 14 Code of Federal Regulations Part 91 personal flight. Pilot reported that he and a friend were on a scenic flight from the Homer Airport (HOM), Homer, Alaska, to the Soldotna Airport (SXQ), Soldotna, Alaska. En route he noticed the engine was not making enough power for the set power setting. At full throttle the engine was only producing about 2,400 rpm. He ran through checklist memory items for loss of engine power, which included applying carburetor heat; however, there was no change in the engine power. The pilot also opened both wing tanks to increase fuel in the header tank, which also resulted in no change. He then noticed the oil pressure gauge and oil temperature gauge both indicated zero. The pilot initiated a climb to clear rising terrain when the engine started to vibrate violently and then lost all power. He initiated a forced landing on to a road and, after touching down, he veered left to avoid cars. The airplane impacted a guardrail and then nosed over. The airplane sustained substantial damage to the fuselage and wings. A postaccident examination of the engine revealed that the crankshaft’s No. 1 main bearing had spun, smearing metal into the crankcase and blocking the oil port. Numerous fragments of bearing material were found inside the case. The owner was not able to provide maintenance records for the engine. While en route during a scenic flight, the pilot noticed the engine was not making enough power for the set power setting and the oil pressure and oil temperature gauges both indicated zero. He started a climb to clear rising terrain when the engine started to vibrate violently and then the engine lost all power. The pilot made a forced landing on to a road and, after touching down, veered to avoid traffic. The airplane impacted a guardrail and nosed over, sustaining substantial damage to the fuselage and wings. A postaccident examination of the engine revealed that the crankshaft’s No. 1 main bearing had spun, smearing metal into the crankcase and blocking the oil port. Numerous fragments of bearing material were found inside the engine. Based on the available information, it is likely that the shift of the No. 1 main bearing resulted in a lack of lubrication and subsequent failure of the engine. The reason for the bearing shift was not determined; the owner was not able to provide maintenance records for the engine. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12
NTSB Findings
FAA avdata. C = Cause, F = Factor.
- — Aircraft-Aircraft power plant-Engine (reciprocating)-Recip eng oil sys-Damaged/degraded
- — Aircraft-Aircraft power plant-Engine (reciprocating)-Recip engine power section-Damaged/degraded
Verbatim from NTSB's published report. Source file
NTSB_2023_ANC23LA053.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
Matched on aircraft type or causal vocabulary (maintenance). All research papers
- Embry-Riddle Scholarly Commons 2026 · Journal article (IJAAA) From Reactive to Predictive: A hybrid Trust-Mediated Adoption Framework for Data-Driven Maintenance in Distributed-Authority Aviation Environments
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- Semantic Scholar 2025 · Article (Applied Sciences) Decision-Making Framework for Aviation Safety in Predictive Maintenance Strategies
The implementation of predictive maintenance (PM) in aviation presents unique challenges due to strict safety requirements, complex operational environments, and regulatory constraints.
- Semantic Scholar 2024 · Article (Defence Science Journal) Modelling of Human Factors in Aviation Maintenance Using HFACS ME Human Factors Analysis and Classification System Maintenance Extension and Bayesian Network
Aircraft maintenance is a complex task involving a skilled human workforce, spare parts, and various other resources. Human factors are an inherent element of the human workforce.
- Embry-Riddle Scholarly Commons 2024 · Journal article (JAAER) A New Trajectory in UAV Safety: Leveraging Reinforcement Learning for Distance Maintenance Under Wind Variations
In the field of aviation, safety is a critical cornerstone, and the operation of Unmanned Aerial Vehicle (UAV) systems is deeply connected with this principle.
- Embry-Riddle Scholarly Commons 2024 · Journal article (JAAER) Low-Resource Automatic Speech Recognition Domain Adaptation – A Case-Study in Aviation Maintenance
With timeliness and efficiency being critical in the aviation maintenance industry, the need has been growing for smart technological solutions that optimize and streamline the different underlying ta…