# NTSB WPR22LA099: Aeronca 11AC, N9500E, Napa, CA, February 8, 2022 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: February 8, 2022, 08:45 local (16:45 UTC) - Place: Napa, CA · 1575 Capell Rd - Coordinates: 38.462184, -122.2149 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.4622&lon=-122.2149&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA - NTSB case key (mKey): 104651 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR22LA099 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/104651/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=104651 - Page: https://openairdocs.org/ntsb/WPR22LA099 ## Probable cause The loss of engine power for undetermined reasons, which resulted in an off-airport landing on unimproved terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Ignition system: magneto/distributor](https://openairdocs.org/ntsb-findings/01057414): Aircraft › Aircraft power plant · Not serviced/maintained; cases with it: [Aeronca 11AC, 1 case](https://openairdocs.org/ntsb-findings/01057414/cases.md?model=0191102), [All aircraft, 101 cases](https://openairdocs.org/ntsb-findings/01057414/cases.md) - [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Owner/builder; cases with it: [Aeronca 11AC, 2 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=0191102), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md) - [Inspection: scheduled/routine inspection](https://openairdocs.org/ntsb-findings/02061520): Personnel issues › Task performance · Owner/builder; cases with it: [Aeronca 11AC, 1 case](https://openairdocs.org/ntsb-findings/02061520/cases.md?model=0191102), [All aircraft, 167 cases](https://openairdocs.org/ntsb-findings/02061520/cases.md) - [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Unknown/Not determined (probable cause); cases with it: [Aeronca 11AC, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=0191102), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) (defining event); cases with it: [Aeronca 11AC, 2 cases](https://openairdocs.org/ntsb-events/000/sequence.md?model=0191102), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md) - [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Aeronca 11AC, 16 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=0191102), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot was flying the airplane to an airport about 48 miles from the departure airport when, 30 minutes after departure while in cruise flight, the engine lost all power. The pilot then verified engine controls were at their correct positions and adjusted the carburetor heat setting. There was no change in engine power, so he made a mayday call and landed the airplane in an open field, during which the airplane sustained substantial damage to the lower fuselage. A postaccident examination of the engine revealed that both magnetos produced a weak spark on all ignition leads when the propeller was rotated by hand. The left magneto was found to be in poor condition and did not function within the manufacturer’s specifications. Internal examination of the left magneto revealed that the distributor axle bearing had failed, and the distributor gear was missing about half of its gear teeth. The right magneto was found in poor overall condition and was missing about 6 distributor gear teeth; however, it did function within the manufacturer’s specifications. A review of maintenance records revealed no indication that the left and right magnetos were serviced, to include inspections or overhauls, since the engine’s last overhaul 15 years (or about 400 hours) before the accident. While the left magneto was not functioning within the manufacturers specifications, and the right magneto functioned within the manufacturers specifications, it would not result a total loss of engine power. The reason for the total loss of engine power could not be determined. ## Factual narrative On February 8, 2022, about 0845 pacific standard time, an Aeronca 11AC Chief, N9500E, was substantially damaged when it was involved in an accident near Napa, California. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he departed University Airport (EDU), Davis, California, and was enroute to Sonoma County Airport (STS), Santa Rosa, California. At approximately 30 minutes into the flight, about 20 nm north of Napa, California, the engine lost all power. The pilot stated that the engine “got quiet,” the “tach[ometer] dropped,” and the airplane could not maintain altitude. He immediately verified the throttle was full forward and then pulled the carburetor heat to the OPEN position. However, the airplane continued to descend. The pilot made mayday calls and performed a forced landing to a field, during which the airplane sustained substantial damage to the fuselage tubular frame. A postaccident examination of the airframe did not reveal any preimpact mechanical anomalies. Examination of the engine cylinders and case did not reveal any indications of catastrophic engine failure. Mechanical continuity was established throughout the rotating group, valvetrain, and accessory section as the crankshaft was manually rotated at the propeller by hand. Thumb compression was achieved at all four cylinders and the valves displayed normal lift when the crankshaft was rotated. When the propeller was rotated by hand, spark was produced on all ignition leads, however, was “extremely weak.” Both magnetos were removed for further examination. The mechanic who completed a postaccident examination of the right magneto stated that the magneto was unmaintained and in poor overall condition. The point cover screws were both stripped and cross threaded but still had the safety wire in place. The distributor axle set screw and bushing was worn and loose. The distributor gear had six gear teeth damaged and partially missing. The right magneto functioned within manufacturer standards during its bench test. The left magneto was also unmaintained and in poor overall condition. The axle set screw was displaced and found at the bottom of the magneto housing. The distributor gear had over half of its teeth worn or missing. The distributor axle bushing was loose and worn, and the distributor axle bearing had failed. The left magneto functioned outside manufacturer standards during its bench test. A review of the engine logbook revealed that the engine was last overhauled in 2007, about 400.7 hours prior to the accident. Subsequent log entries did not reveal that either magneto was overhauled or inspected more recently. ## Aircraft - Registration: [N9500E](https://openairdocs.org/aircraft/N9500E), registered now, S/N 11AC-1135, built 1946 (OpenAirDocs) - Reported make and model: AERONCA 11AC (NO SERIES) - Registry model: [Aeronca 11AC](https://openairdocs.org/model/aeronca-11ac) (registry code 0191102) (OpenAirDocs) - Registry engine: [Continental A&C65 series](https://openairdocs.org/engine/continental-a-c65-series) (registry code 17003, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 11AC-1135 - Year built: 1946 - Airframe hours: 2174 - Engines: Continental A-65-8 65 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 17, 2021, 54 hours before - Departed: KEDU, Davis, CA - Destination: KSTS, Santa Rosa, CA - Flight plan: VFR - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 22; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review April 29, 2021; seat: left; restraint: lap only; flight hours: 226 total, 40 in this make and model, 167 as pilot in command, 50 in the last 90 days, 28.3 in the last 30 days, 1.8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 6 statute miles - Lowest ceiling: none - Temperature: 45 °F, dew point 43 °F - Altimeter: 30.32 inHg - Observed at: KAPC, 15 nm away - METAR: KAPC 081654Z COR 00000KT 6SM BR CLR 07/06 A3032 RMK AO2 SLP258 T00720061 ## 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 20220208001499A](https://openairdocs.org/incident/20220208001499A), Feb 8, 2022: Aeronca 11AC, Napa, CA, Minor damage. Inspector[privacy data omitted]interviewed the pilot by phone on 03/24/2022 at approximately 1145. The pilot mentioned that he departed the davis airport(edu)… ## Other investigations on N9500E (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 SEA66F0115](https://openairdocs.org/ntsb/SEA66F0115), Aug 22, 1965: Aeronca 11AC (N9500E), Bellevue, WA, substantial damage ## Docket (9 files) The files NTSB released with the investigation on March 28, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=104651. 10.9 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13341413&FileExtension=pdf&FileName=6120%20099_Redacted-Rel.pdf - Mor pilot (item 2, PDF, 1 page, 66 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16679690&FileExtension=pdf&FileName=MOR%20Pilot%20099-Rel.pdf - Mor FAA post accident exam notes (item 3, PDF, 1 page, 72 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16681083&FileExtension=pdf&FileName=MOR%20FAA%20Exam%20Notes%20099-Rel.pdf - Accident photos (item 4, PDF, 4 pages, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16676771&FileExtension=pdf&FileName=Accident%20Photos%20099-Rel.pdf - Magneto examination notes (item 5, PDF, 2 pages, 55 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16677192&FileExtension=pdf&FileName=Magneto%20Examination_Redacted-Rel.pdf - Engine logbook excerpts (item 6, PDF, 7 pages, 5.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16676951&FileExtension=pdf&FileName=Engine%20Logbook%20Entries%20099_Redacted-Rel.pdf - Meteorology specialist's factual report (item 7, PDF, 6 pages, 485 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14776522&FileExtension=pdf&FileName=WX_WPR22LA099_Specialists_Factual-Rel.pdf - Release of wreckage (item 8, PDF, 2 pages, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16676961&FileExtension=pdf&FileName=Release-of-Wreckage-Form%20N9500E_Redacted-Rel.pdf - Evidence control form (item 9, PDF, 2 pages, 137 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16676470&FileExtension=pdf&FileName=Evidence%20Control%20Form%20099-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.