# NTSB CEN10LA123: Cessna 172N, N24CV, Genoa City, WI, February 14, 2010 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: February 13, 2010, 20:15 local (Feb 14, 2010, 02:15 UTC) - Place: Genoa City, WI - Coordinates: 42.557777, -88.315551 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.5578&lon=-88.3156&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report December 20, 2010 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Bowen Aviation LLC, G & N Aircraft, Inc., FAA-Milwaukee FSDO - NTSB case key (mKey): 75373 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN10LA123 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/75373/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=75373 - Page: https://openairdocs.org/ntsb/CEN10LA123 ## Probable cause A total loss of engine power due to the failure of the bolts that held in place the connecting rods to the engine's No. 3 and No. 4 cylinders as a result of the engine overhaul facility's improper installation of the bolts during a recent overhaul. ## 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 · Failure (probable cause); cases with it: [Cessna 172N, 13 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=2072434), [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 · Incorrect service/maintenance (probable cause); cases with it: [Cessna 172N, 13 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=2072434), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) - [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Cessna 172N, 6 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=2072434), [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. - [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Cessna 172N, 11 cases](https://openairdocs.org/ntsb-events/340/sequence.md?model=2072434), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Cessna 172N, 28 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2072434), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 172N, 31 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2072434), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis The pilot stated that during cruise flight he heard a “loud metallic clicking” sound, followed by a “bang” and a vibration. A few seconds later there was another “bang” and the propeller stopped rotating. He subsequently executed a forced landing to a corn field, where the airplane sustained damage to the firewall, nose landing gear, and wings. A postaccident examination on the engine revealed that the No. 3 and No. 4 engine connecting rod bolts had failed. Metallurgical examination determined that the bolts failed as a result of overstress fractures. No evidence of a fatigue fracture was observed. The teardown examination of the engine revealed that the nuts installed on the No. 1 and No. 2 connecting rod bolts were not tightened to the engine manufacturer’s specifications. Maintenance records indicated that the engine had been overhauled and the airplane returned to service about two weeks prior to the accident. At the time of the accident, the engine had been operated about 68 hours since the overhaul. The lack of proper torque on the intact rod bolts/nuts and the overstress failure of the remaining bolts indicates that the connecting rods were not installed properly during the overhaul procedure. ## Factual narrative On February 13, 2010, about 2015 central standard time, a Cessna model 172N, N24CV, piloted by a commercial pilot, was substantially damaged during a forced landing following a loss of engine power near Genoa City, Wisconsin. The personal cross-country flight was being conducted under 14 Code of Federal Regulations Part 91 without a flight plan. Night visual meteorological conditions prevailed. The pilot sustained minor injuries. The flight departed Aurora Municipal Airport (ARR), Aurora, Illinois, about 1945, with an intended destination of Austin Straubel International Airport (GRB), Green Bay, Wisconsin. The pilot stated that during cruise flight he heard a “loud metallic clicking” sound, followed by a “bang” and a vibration. He noted that a few seconds later there was another “bang” and the propeller stopped rotating. He subsequently executed a forced landing to a corn field. The airplane sustained damage to the firewall, nose landing gear, and wings. A post-accident examination of the engine revealed crankcase fractures in the area of the #3 and #4 cylinders. The engine sump contained approximately 5 quarts of oil at the time of the exam. The oil filter contained metallic fragments. Teardown examination of the engine revealed that the #3 and #4 connecting rod bolts had failed. All four bolts (two common to each connecting rod) failed above the threads, in the shank portion of the bolts. Two of the bolt fragments included the corresponding nuts; however, they were backed off to the end of the bolts. These bolt fragments appeared to have separated from the #3 connecting rod. The remaining two nuts had separated from their corresponding rod bolts. One of the nuts was deformed and scarred consistent with mechanical damage. The other was fragmented. The remaining two sets of connecting rod bolts appeared intact. However, the nuts securing the #1 connecting rod bolts were loosened by applying minimal torque from a wrench, and the nuts securing the #2 connecting rod bolts were finger tight. The #2 connecting rod and cap were not mated, but were separated approximately 1/8 inch. Metallurgical examination of the failed connecting rod bolts revealed features consistent with overstress failure. No evidence of a fatigue fracture was observed on any of the fracture surfaces. Maintenance records indicated that the engine was overhauled on January 12, 2010. It was subsequently installed on the accident airplane on January 28, 2010, at a recording tachometer time of 419.5 hours. The records noted three engine oil changes since overhaul. The most recent oil change was completed on February 11, 2010, at 48.4 hours operation since overhaul. The recording tachometer indicated 487.8 hours (68.3 hours since overhaul) at the time of the post-accident examination. Documentation provided by the engine manufacturer noted that the connecting rod nuts should be tightened to 480 inch-pounds at the time of installation. Overhaul records included a Build Up Check Sheet.The sheet included a line item entitled “Rod Nuts Torqued & Safetied.” For this line item, initials had been placed under both the “Technician” and the “Inspector” columns. A representative of the overhaul facility stated that all connecting rod bolts are replaced and installed as new bolts on overhauled engines. He added that rod bolts are procured directly from the engine manufacturer and not from any third-party manufacturers. ## Aircraft - Registration: [N24CV](https://openairdocs.org/aircraft/N24CV), registered now, S/N 17270186, built 1977 (OpenAirDocs) - Reported make and model: CESSNA 172N - Registry model: [Cessna 172N](https://openairdocs.org/model/cessna-172n) (registry code 2072434) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17270186 - Airframe hours: 3822 - Engines: LYCOMING O-320 SERIES 160 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Bowen Aviation LLC - Registered owner: Bowen Aviation LLC - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 28, 2010, 68 hours before - Departed: ARR, Aurora, IL - Destination: GRB, Green Bay, WI ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 30; injuries: minor; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review October 9, 2008; seat: left; flight hours: 1,599 total, 1,167 in this make and model, 1,484 as pilot in command, 209 in the last 90 days, 75 in the last 30 days, 9 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night - Wind: 250° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: 3,600 ft broken - Temperature: 14 °F, dew point 7 °F - Altimeter: 29.89 inHg - Observed at: ENW, 18 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 20100213027259A](https://openairdocs.org/incident/20100213027259A), Feb 13, 2010: Cessna 172N, Genoa City, WI, Substantial damage. N24CV was cruising at 3500' MSL when it's propeller seized. The pilot made an emergency landing in a nearby cornfield where the aircraft sustained substantial… ## Other investigations on N24CV (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 OPS24LA004](https://openairdocs.org/ntsb/OPS24LA004), Oct 27, 2023: Cessna 172N (N24CV), Long Beach, CA, incident, no damage. Probable cause: The local controller’s poor judgment in prioritization of their ground traffic ahead of their airborne traffic, that became a distraction and led to a loss of situational awareness resulting in a… ## Docket (8 files) The files NTSB released with the investigation on September 2, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=75373. 3.0 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40333081&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Engine Examination Record (item 2, .PDF, 131 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40333082&FileExtension=.PDF&FileName=Engine%20Examination%20Record-Redacted.PDF - Airframe Logbook -- Excerpts (item 3, .PDF, 671 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40333083&FileExtension=.PDF&FileName=Airframe%20Logbook%20--%20Excerpts-Redacted.PDF - Engine Logbook (item 4, .PDF, 370 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40333091&FileExtension=.PDF&FileName=Engine%20Logbook-Redacted.PDF - Engine Overhaul Documentation -- Excerpts (item 5, .PDF, 320 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40333086&FileExtension=.PDF&FileName=Engine%20Overhaul%20Documentation%20--%20Excerpts-Redacted.PDF - Materials Laboratory Factual report 10-052 (item 6, .PDF, 141 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40332869&FileExtension=.PDF&FileName=Materials%20Laboratory%20Factual%20report%2010-052-Master.PDF - Conversation Record -- Overhaul Facility (item 7, .PDF, 52 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40333087&FileExtension=.PDF&FileName=Conversation%20Record%20--%20Overhaul%20Facility-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 8, .PDF, 52 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40333088&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.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.