# NTSB CEN22LA141: Cessna 150M, N63246, Brodhead, WI, March 13, 2022 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: March 13, 2022, 12:40 local (17:40 UTC) - Place: Brodhead, WI - Coordinates: 42.596427, -89.374571 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.5964&lon=-89.3746&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern downwind: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Flight Standards District Office - ADs cited in the narratives: [AD 94-05-05 R1](https://openairdocs.org/ad/94-05-05-R1) (OpenAirDocs) - NTSB case key (mKey): 104769 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN22LA141 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/104769/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=104769 - Page: https://openairdocs.org/ntsb/CEN22LA141 ## Probable cause A loss of engine power due to the fatigue fracture of the No. 1 cylinder’s rocker shaft bosses, which resulted in a forced landing into uneven terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Terrain: rough terrain](https://openairdocs.org/ntsb-findings/03021015): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Cessna 150M, 2 cases](https://openairdocs.org/ntsb-findings/03021015/cases.md?model=2071830), [All aircraft, 442 cases](https://openairdocs.org/ntsb-findings/03021015/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 150M, 8 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=2071830), [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. - [Approach-VFR pattern downwind: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Cessna 150M, 14 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=2071830), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) ## Analysis The pilots reported the engine began to vibrate and lose power while on the downwind leg in the traffic pattern. The pilot in the right seat took control and attempted to conduct a downwind forced landing to the runway, but the airplane’s flight path continued beyond the end of the runway into uneven terrain and the airplane nosed over. The airplane sustained substantial damage to both wings and the vertical stabilizer. Postaccident examination revealed the No. 1 cylinder rocker shaft bosses were fractured. Further examination of fracture surfaces with a stereomicroscope revealed fatigue crack initiation at and progression from the rocker shaft bore hole. In 1996, based on a history of fatigue cracking of cylinder rocker shaft bosses, the Federal Aviation Administration issued an airworthiness directive (AD) that required inspection of the cylinder shaft rocker bosses at the next overhaul or cylinder removal. Since the engine was last overhauled in 1978 and the No. 1 cylinder was last removed 1991, compliance with the AD was not required for the accident airplane’s No. 1 cylinder. ## Factual narrative On March 13, 2022, about 1240 central daylight time, a Cessna 150M, N63246, was substantially damaged when it was involved in an accident at Brodhead Airport (C37), Brodhead, Wisconsin. The two pilots sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilots reported that they flew two visual approaches without incident to runway 27 at C37. While on downwind for a third approach, the engine began to vibrate violently and lost power. The pilots attempted a forced landing to runway 9. The flight path continued beyond the end of the turf runway and the airplane nosed over, which resulted in damage to both wings and the vertical stabilizer. During the postaccident examination of the engine the No. 1 cylinder valve rocker cover was removed and the two rocker arms, pivot shaft, and pieces of the cylinder shaft rocker bosses came off freely with the rocker cover. Examination of the rocker boss fracture surfaces with the aid of a stereomicroscope revealed fatigue crack initiation at and progression from the rocker shaft bore hole. In 1996, the Federal Aviation Administration issued an AD 94-05-05 R1 that required inspection of the cylinder rocker shaft bosses at the next engine overhaul or cylinder removal, whichever occurred first. The AD was issued based on a history of fatigue cracking and separation of cylinder rocker shaft bosses of the installed cylinders. A review of maintenance records indicated the AD was not required to be complied with for the installed cylinders since the engine was last overhauled in 1978 and the No. 1 cylinder was last removed in 1991. A search of previous National Transportation Safety Board reports revealed one accident after the AD issuance that involved failure of rocker shaft bosses. This accident occurred on June 27, 1998. ## Aircraft - Registration: [N63246](https://openairdocs.org/aircraft/N63246), registered now, S/N 15077200, built 1975 (OpenAirDocs) - Reported make and model: CESSNA 150M - Registry model: [Cessna 150M](https://openairdocs.org/model/cessna-150m) (registry code 2071830) (OpenAirDocs) - Registry engine: [Continental 0-200 series](https://openairdocs.org/engine/continental-0-200-series) (registry code 17020, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 15077200 - Year built: 1975 - Airframe hours: 3832 - Engines: Continental O-200-A 100 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 13, 2021, 50 hours before - Departed: EFT, Monroe, WI - Destination: C37, Brodhead, WI - Airport: C37, Brodhead, runway 09, 2,430 × 155 ft, grass/turf ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; injuries: minor; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review July 20, 2021; seat: left; restraint: lap only; flight hours: 190 total, 190 in this make and model - Pilot; age 61; injuries: minor; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review March 5, 2020; seat: right; restraint: lap only; flight hours: 934 total, 400 in this make and model, 22 in the last 90 days, 10 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 280° at 13 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 43 °F, dew point 25 °F - Altimeter: 29.91 inHg - Observed at: KEFT, 10 nm away - METAR: KEFT 131735Z AUTO 28013KT 10SM CLR 06/M04 A2991 RMK AO2 T00571036 ## 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 20220313003189A](https://openairdocs.org/incident/20220313003189A), Mar 13, 2022: Cessna 150M, Broadhead, WI, Substantial damage. Pilot was practicing take off and goes. On 2nd attempt, pilot departed runway rwy 27, entered a left downwind for rwy 27 and at 1220 ft, the engine began to… ## Docket (9 files) The files NTSB released with the investigation on August 15, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=104769. 15.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14069121&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Statement of pilot (item 2, PDF, 1 page, 153 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14068634&FileExtension=pdf&FileName=Statement%20of%20Pilot_Redacted-Rel.pdf - Photos (item 3, PDF, 2 pages, 384 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14070498&FileExtension=pdf&FileName=Photos-Rel.pdf - Engine examination (item 4, PDF, 1 page, 50 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14099718&FileExtension=pdf&FileName=Engine%20Examination-Rel.pdf - Engine maintenance logs (item 5, PDF, 26 pages, 9.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14068932&FileExtension=pdf&FileName=Engine%20Logs_Redacted-Rel.pdf - FAA airworthiness directive (1996) (item 6, PDF, 4 pages, 23 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14069351&FileExtension=pdf&FileName=FAA%20Airworthiness%20Directive%20-%20AD-94-05-05-Rel.pdf - NTSB recommendation letter (item 7, PDF, 2 pages, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14068950&FileExtension=pdf&FileName=NTSB%20Rec%20Letter%20------_Redacted-Rel.pdf - Materials laboratory factual report 23-012 (item 8, PDF, 8 pages, 8 photos, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15205876&FileExtension=pdf&FileName=Materials%20Laboratory%20Factual%20Report%2023-012-Rel.pdf - Materials laboratory attachment 1 - Continental motors sb M73-13 (item 9, PDF, 2 pages, 103 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15205762&FileExtension=pdf&FileName=M73-13-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.