# NTSB ANC23LA053: Aeronca 7DC, N83391, Ninilchik, AK, July 13, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: July 12, 2023, 16:20 local (Jul 13, 2023, 00:20 UTC) - Place: Ninilchik, AK · Highway - Coordinates: 60.037204, -151.63662 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=60.0372&lon=-151.6366&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: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Alaska Regional Office - Parties: FAA - NTSB case key (mKey): 192670 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC23LA053 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192670/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192670 - Page: https://openairdocs.org/ntsb/ANC23LA053 ## Probable cause 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. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng oil sys](https://openairdocs.org/ntsb-findings/01058550): Aircraft › Aircraft power plant · Damaged/degraded (probable cause); cases with it: [Aeronca 7DC, 1 case](https://openairdocs.org/ntsb-findings/01058550/cases.md?model=2110116), [All aircraft, 130 cases](https://openairdocs.org/ntsb-findings/01058550/cases.md) - [Engine (reciprocating): recip engine power section](https://openairdocs.org/ntsb-findings/01058520): Aircraft › Aircraft power plant · Damaged/degraded (probable cause); cases with it: [Aeronca 7DC, 1 case](https://openairdocs.org/ntsb-findings/01058520/cases.md?model=2110116), [All aircraft, 233 cases](https://openairdocs.org/ntsb-findings/01058520/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: [Aeronca 7DC, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=2110116), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Aeronca 7DC, 3 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2110116), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Aeronca 7DC, 4 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=2110116), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis 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. ## 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. ## Aircraft - Registration: [N83391](https://openairdocs.org/aircraft/N83391), registered now, S/N 7AC2058, built 1946 (OpenAirDocs) - Reported make and model: AERONCA 7DC - Registry model: [Aeronca 7DC](https://openairdocs.org/model/aeronca-7dc) (registry code 2110116) (OpenAirDocs) - Registry engine: [Continental C85 series](https://openairdocs.org/engine/continental-c85-series) (registry code 17008, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 7AC2058 - Year built: 1946 - Airframe hours: 4542.6 - Engines: Continental C-85-12 96 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, March 3, 2023, 55 hours before - Departed: PAHO, Homer, AK - Destination: PASX, Soldotna, AK - Airport: PASX, Soldotna - Equipment: Electronic flight bag or handheld device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 26; injuries: none; private; airplane ratings: single-engine land; medical: class 1, with waivers/limitations; seat: front; restraint: 3-point; flight hours: 79.9 total, 17.9 in this make and model, 23.5 as pilot in command, 50.7 in the last 90 days, 21.9 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 250° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: 5,000 ft broken - Temperature: 57 °F, dew point 54 °F - Altimeter: 30.16 inHg - Observed at: PAHO ## 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 20230712014669A](https://openairdocs.org/incident/20230712014669A), Jul 12, 2023: Aeronca 7DC, Ninilchik, AK, Substantial damage. Pilot was returning from homer with a non-certificated passenger. He noticed that his oil pressure was fluctuating, and he was losing power. He stated he knew… ## Other investigations on N83391 (1) 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. - [NTSB ANC19LA024](https://openairdocs.org/ntsb/ANC19LA024), Jun 12, 2019: Aeronca 7DC (N83391), Nome Creek, AK, substantial damage. Probable cause: The failure of the airplane's structural tubing due to corrosion, which resulted in a tailwheel separation and a subsequent loss of control. Also causal was the mechanic's failure to perform a… ## Docket (4 files) The files NTSB released with the investigation on May 16, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192670. 6.8 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=16211976&FileExtension=pdf&FileName=ANC23LA053%206120_Redacted-Rel.pdf - Engine examination (item 2, PDF, 12 pages, 2.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16212194&FileExtension=pdf&FileName=ANC23LA053%20Engine%20exam%202-Rel.pdf - No maintenace records (item 3, PDF, 1 page, 63 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16211619&FileExtension=pdf&FileName=ANC23LA053%20no%20maintence%20records-Rel.pdf - Photos (item 4, PDF, 3 pages, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16212584&FileExtension=pdf&FileName=ANC23LA053%20Investigative%20photographs-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.