# NTSB ERA21LA091: Cessna 172, N8311X, Pleasant Valley, NY, December 27, 2020 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: December 27, 2020, 15:20 local (20:20 UTC) - Place: Pleasant Valley, NY · swampy wooded terrain - Coordinates: 41.717864, -73.74979 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.7179&lon=-73.7498&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern final: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO, Textron, Champion Aerospace - NTSB case key (mKey): 102466 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA21LA091 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102466/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102466 - Page: https://openairdocs.org/ntsb/ERA21LA091 ## Probable cause A total loss of engine power due to failure of the magnetos, which were not overhauled in accordance with the manufacturer’s time specifications. ## 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 · Failure (probable cause); cases with it: [Cessna 172C, 1 case](https://openairdocs.org/ntsb-findings/01057414/cases.md?model=2072408), [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 (probable cause); cases with it: [Cessna 172C, 1 case](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=2072408), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern final: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Cessna 172C, 4 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2072408), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 172C, 4 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2072408), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 172C, 4 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2072408), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis The student pilot was practicing takeoffs and landings when the engine sputtered and lost all power while on final approach. The student pilot tried to restart the engine to no avail and subsequently made a forced landing in a wooded area. The airplane came to rest inverted in swampy terrain amongst trees. The magnetos were removed from the engine during the postaccident examination, and they failed to produce sparks when tested. Further examination of the magnetos revealed extensive corrosion present on the coil laminations between the coil and magnet. It is likely the rotor was unable to transmit electricity to the coil and therefore the magneto was unable to produce a spark. The magneto manufacturer maintenance manual and overhaul manual states the magneto time in service allowance is the time before overhaul for the engine or 12 years. The magnetos had not been overhauled and were 14 and 23 years old. No other engine anomalies were identified that would have prevented normal operation. ## Factual narrative On December 27, 2020, about 1520 eastern standard time, a Cessna 172C, N8311X, was substantially damaged when it was involved in an accident near Pleasant Valley, New York. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. According to the student pilot, after a normal preflight inspection she departed with 27 gallons of fuel and planned to remain in the traffic pattern to practice takeoffs and landings. On the downwind leg of the traffic pattern the tachometer indication dropped out of the normal operating range so she announced over the radio that she was experiencing an engine malfunction. She deployed partial flaps and turned the carburetor heat ON. Shortly thereafter, on final approach, the engine sputtered and lost all power. The student pilot performed the emergency checklist, cycled the magnetos, declared an emergency and performed a forced landing in a wooded area. The airplane came to rest inverted in swampy terrain amongst trees and sustained substantial damage to the wings and fuselage. The wreckage recovery was delayed about 8 months. During this time the propeller, instruments from the instrument panel, and the left yoke were taken from the airplane and not recovered. The last entry in the engine logbook stated all of the lower spark plugs were replaced due to “rough mag[neto] drop on run up” about 4 months before the accident. The airplane accumulated about 9 hours between the time the maintenance was performed and the accident. A postaccident examination was conducted during which the engine’s crankshaft was rotated by hand, and internal and valvetrain continuity was established. Examination of the cylinders with a lighted borescope revealed no anomalies. The cylinders and spark plugs contained dirt and debris from the swamp. The impulse coupling magnetos did not produce spark when turned by hand. The magnetos were removed and placed on a test bench; neither magneto produced a spark. Further examination of the magnetos revealed extensive corrosion present on the coil laminations. The left magneto had rust, debris, and corrosion present in the magneto and distributor gear housing; extensive rust was found around the coil laminations, housing, and the magnet. The right magneto had rust on the coil lamination and arcing throughout the distributor gear. The exterior housing of the magnetos was undamaged. The Champion Aerospace Magneto Maintenance and Overhaul Manual states the magneto time in service allowance is the Time Before Overhaul for the engine or 12 years. According to maintenance records, the engine was overhauled in 1984, 36 years prior to the accident. The right magneto was manufactured in 2006, the left magneto in 1997, 14 and 23 years respectively, before the accident. ## Aircraft - Registration: [N8311X](https://openairdocs.org/deregistered/N8311X-2022-05-09), registration cancelled 2022-05-09, S/N 17248811, built 1961 (OpenAirDocs) - Reported make and model: CESSNA 172 (C) - Registry model: [Cessna 172C](https://openairdocs.org/model/cessna-172c) (registry code 2072408) (OpenAirDocs) - Registry engine: [Continental 0-300 series](https://openairdocs.org/engine/continental-0-300-series) (registry code 17022, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17248811 - Year built: 1961 - Airframe hours: 5634 - Engines: CONT MOTOR 0-300 SER 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 17, 2020 - Destination: Same as departure - Airport: 44N, Sky Acres Airport, runway 17, 3,828 × 60 ft, asphalt - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 17; injuries: minor; student; medical: class 3, without waivers/limitations; last flight review October 2, 2020; seat: left; restraint: 3-point; flight hours: 38.7 total, 38.7 in this make and model, 38.7 as pilot in command, 5.7 in the last 90 days, 1.8 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 36 °F, dew point 18 °F - Altimeter: 30.28 inHg - Observed at: POU, 8 nm away - METAR: KPOU 271953Z 23005KT 10SM CLR 02/M08 A3028 RMK AO2 SLP251 T00221078 ## 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 20201227018899A](https://openairdocs.org/incident/20201227018899A), Dec 27, 2020: Cessna 172C, Pleasant Vallle, NY, Substantial damage. On December 27, 2020, about 1500 eastern standard time, a Cessna 172C, N8311X, was substantially damaged when it was involved in an accident approximately 0.5… ## Docket (8 files) The files NTSB released with the investigation on January 30, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102466. 12.1 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 12 pages, 5.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13272734&FileExtension=pdf&FileName=NTSB%20pilot%20incident%20report_Redacted-Rel.pdf - Airframe and engine examination (item 2, PDF, 4 pages, 803 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14012347&FileExtension=pdf&FileName=ERA21LA091-%20Airframe%20and%20Engine%20Exam%20notes-Rel.pdf - Magneto examination (item 3, PDF, 4 pages, 527 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14011464&FileExtension=pdf&FileName=Magneto%20Examination%20Notes-Rel.pdf - Excerpt from champion maintenance manual (item 4, PDF, 14 pages, 598 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14033986&FileExtension=pdf&FileName=Excerpt%20from%20mm-Rel.pdf - Maintenance records (item 5, PDF, 6 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13993964&FileExtension=pdf&FileName=maintenance%20records_Redacted-Rel.pdf - Statement of party representatives to NTSB investigation (item 6, PDF, 15 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13993555&FileExtension=pdf&FileName=NTSB%20Party%20Form_Redacted-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 7, PDF, 1 page, 386 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13337455&FileExtension=pdf&FileName=Wreckage%20release_Redacted-Rel.pdf - Photos (item 8, PDF, 4 pages, 484 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13336744&FileExtension=pdf&FileName=Photo%20Array-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.