# NTSB CEN17LA006: Cessna 172K, N46377, Wilmot, WI, October 4, 2016 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 4, 2016, 15:11 local (20:11 UTC) - Place: Wilmot, WI - Coordinates: 42.511665, -88.208885 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.5117&lon=-88.2089&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report January 18, 2017 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 94142 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN17LA006 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/94142/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=94142 - Page: https://openairdocs.org/ntsb/CEN17LA006 ## Probable cause A failure of the No. 1 piston pin plug due to corrosion in the cylinder barrel, which resulted in oil contamination, oil starvation to the crankshaft connecting rod bearings, and a subsequent partial loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Fatigue/wear/corrosion (probable cause); cases with it: [Cessna 172K, 2 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=2072430), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Cessna 172K, 2 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=2072430), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Cessna 172K, 3 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=2072430), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 172K, 33 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072430), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The private pilot stated that the engine experienced a partial loss of power shortly after takeoff on the local flight. In an effort to regain power, the pilot switched fuel tanks, applied carburetor heat, and richened the fuel mixture, but the engine continued to operate at reduced power. The pilot attempted to land at a nearby airport; however, he overshot the runway and decided to perform a forced landing to an adjacent cornfield. During the landing, the right wing impacted the corn, and the airplane came to rest upright. Partial disassembly of the engine revealed a failure of the No. 1 piston pin plug due to corrosion in the No. 1 cylinder barrel. The plug failure resulted in significant oil contamination and subsequent oil starvation and damage to the crankshaft connecting rod bearings. The damage to the bearings resulted in the partial loss of engine power. ## Factual narrative On October 4, 2016, at 1511 central daylight time, a Cessna 172K single-engine airplane, N46377, impacted a cornfield during a forced landing following a partial loss of engine power while maneuvering near Wilmot, Wisconsin. The private pilot, who was the sole occupant, was not injured, and the airplane sustained substantial damage to the right wing. The airplane was registered to 696 Corp, Grayslake, Illinois, and operated by a private individual as a Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed at the time of the accident and a flight plan was not filed. The flight departed the Burlington Municipal Airport (BUU), Burlington, Wisconsin, about 1445. According to the pilot, while maneuvering after takeoff from BUU, the engine began to lose power. The pilot then switched fuel tanks, applied carburetor heat, full rich mixture, but the engine remained at reduced power. The pilot attempted to land at Westosha Airport, Wilmot, Wisconsin, however, he overshot the runway. The pilot then decided to execute a forced landing to an adjacent cornfield. During the forced landing, the right wing impacted the corn, and the airplane came to rest upright. The accident engine was a 150-horsepower, four cylinder, Lycoming O-320-E2D engine, serial number L-22806-27A. It was examined at the facilities of Myers Aviation, Oshkosh, Wisconsin, under the supervision of the National Transportation Safety Board (NTSB) investigator and inspectors from the Federal Aviation Administration (FAA). Visual examination of engine exterior and components revealed no anomalies that would have precluded normal operation. The engine oil filter was removed and disassembled. The internal filter displayed heavy deposits of metal material. Due to the metal deposits in the oil filter, the engine was disassembled. Partial disassembly of the engine revealed the number 1 cylinder piston pin plug was destroyed and metal debris was noted in the engine oil and engine oil filter. The engine crankshaft and connecting rods displayed discoloration and heat signatures consistent with oil starvation. The number 3 and 4 connecting rod bearings were extruded and melted from the rod journals. The cylinder bores displayed corrosion and discoloration on their respective inner surfaces. According to the engine records, the engine underwent its most recent annual inspection on October 1, 2015, at a total time of 3,160 hours, and 1,176 hours since major overhaul. At the time of the accident, the engine had accumulated 34 hours since its inspection. ## Aircraft - Registration: [N46377](https://openairdocs.org/deregistered/N46377-2018-09-04), registration cancelled 2018-09-04, S/N 17257226, built 1968 (OpenAirDocs) - Reported make and model: CESSNA 172K - Registry model: [Cessna 172K](https://openairdocs.org/model/cessna-172k) (registry code 2072430) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17257226 - Year built: 1968 - Airframe hours: 3194 - Engines: LYCOMING O-320-E2D 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 1, 2015, 34 hours before - Departed: BUU, Burlington, WI - Destination: PWK, Wheeling, IL - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 72; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3; last flight review May 1, 2015; seat: left; restraint: lap only; flight hours: 1,042 total, 900 in this make and model, 1,042 as pilot in command, 1 in the last 90 days, 1 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 140° at 6 knots, gusting 14 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 52 °F - Altimeter: 30.02 inHg - Observed at: BUU, 11 nm away ## 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 20161004019869A](https://openairdocs.org/incident/20161004019869A), Oct 4, 2016: Cessna 172K, Wilmont, WI, Substantial damage. On October 04, 2016 N46377 a Cessna 172 (CE-172) was en route from burlington, WI (kbuu) to chicago executive airport (kpwk) prospect heights, IL at 2,200 feet… ## Other investigations on N46377 (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 FTW72FRA38](https://openairdocs.org/ntsb/FTW72FRA38), Feb 4, 1972: Cessna 172K (N46377), Sugar Land, TX, minor damage, 1 fatal ## Docket (3 files) The files NTSB released with the investigation on November 9, 2016, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=94142. 4.9 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40446276&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Excerpt of Engine Records (item 2, .PDF, 462 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40446277&FileExtension=.PDF&FileName=Excerpt%20of%20Engine%20Records-Master.PDF - Photo Array (item 3, .PDF, 5 photos, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40446278&FileExtension=.PDF&FileName=Photo%20Array-Master.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.