# NTSB CEN25LA013: Rotorway Exec, N314AC, Plymouth, IN, October 11, 2024 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: October 11, 2024, 16:50 local (20:50 UTC) - Place: Plymouth, IN - Coordinates: 41.365131, -86.300258 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.3651&lon=-86.3003&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern base: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA - NTSB case key (mKey): 195315 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN25LA013 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/195315/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=195315 - Page: https://openairdocs.org/ntsb/CEN25LA013 ## Probable cause A loss of control due to the failed forward tail rotor belt as a result of the owner’s failure to follow the helicopter manufacturer’s tail rotor belt replacement recommendations. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance/inspections: time limits](https://openairdocs.org/ntsb-findings/01010510): Aircraft › Aircraft handling/service · Incorrect service/maintenance; cases with it: [Colbert Anthony Brian COLBERT/EXEC, 1 case](https://openairdocs.org/ntsb-findings/01010510/cases.md?model=056148K), [All aircraft, 17 cases](https://openairdocs.org/ntsb-findings/01010510/cases.md) - [Tail rotor](https://openairdocs.org/ntsb-findings/01046400): Aircraft › Aircraft propeller/rotor · Failure (probable cause); cases with it: [Colbert Anthony Brian COLBERT/EXEC, 1 case](https://openairdocs.org/ntsb-findings/01046400/cases.md?model=056148K), [All aircraft, 23 cases](https://openairdocs.org/ntsb-findings/01046400/cases.md) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Colbert Anthony Brian COLBERT/EXEC, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=056148K), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Action: lack of action](https://openairdocs.org/ntsb-findings/02041030): Personnel issues › Action/decision · Maintenance personnel; cases with it: [Colbert Anthony Brian COLBERT/EXEC, 1 case](https://openairdocs.org/ntsb-findings/02041030/cases.md?model=056148K), [All aircraft, 792 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md) - [Maintenance: replacement](https://openairdocs.org/ntsb-findings/02062020): Personnel issues › Task performance · Owner/builder; cases with it: [Colbert Anthony Brian COLBERT/EXEC, 1 case](https://openairdocs.org/ntsb-findings/02062020/cases.md?model=056148K), [All aircraft, 70 cases](https://openairdocs.org/ntsb-findings/02062020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Colbert Anthony Brian COLBERT/EXEC, 1 case](https://openairdocs.org/ntsb-events/040/sequence.md?model=056148K), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Approach-VFR pattern base: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Colbert Anthony Brian COLBERT/EXEC, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=056148K), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Autorotation: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Colbert Anthony Brian COLBERT/EXEC, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=056148K), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The helicopter owner/pilot reported that while he and his flight instructor were practicing an autorotation, the flight instructor heard a noise. Shortly thereafter, the helicopter started to yaw to the left and the airspeed decreased. The flight instructor took over control of the helicopter and initiated an autorotation to a corn field. The right skid caught the ground, and the helicopter rolled onto its right side. The main rotor and fuselage sustained substantial damage. A postaccident examination revealed that the forward tail rotor belt broke. The belt was found frayed at the separation point. A review of the tail rotor maintenance records revealed that the tail rotor belts had not been replaced since 2006. The manufacturer recommends tail rotor belt replacement at 250 hours, 2 years, or as needed upon conditional inspections, whichever comes first. The operator reported that before the accident the belts appeared to be in satisfactory condition but acknowledged they were beyond the 2-year service life and should have been replaced. ## Factual narrative On October 11, 2024, about 1650 eastern daylight time, a Rotorway Executive 90, N314AC, was substantially damaged when it was involved in an accident near Plymouth, Indiana. The two pilots sustained minor injuries. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The owner and his flight instructor were flying the helicopter so the owner could gain proficiency. While preparing to practice an autorotation in the traffic pattern, the flight instructor told the owner that he heard a noise. Shortly thereafter, the nose of the helicopter started to yaw to the left. Airspeed began to slow, and the left yaw accelerated. The flight instructor took control of the helicopter and autorotated into a cornfield. The right skid caught the ground; the helicopter rolled onto its side, and came to rest on its right side. The main rotor and fuselage were substantially damaged. A postaccident examination revealed that the forward tail rotor drive belt was broken. The belt was frayed at the separation point. According to the owner, who is also an airframe and powerplant mechanic, the helicopter was in storage for several years before he purchased it in September 2024. A review of the tail rotor maintenance records revealed that after purchase, the owner inspected the tail rotor pulleys, bearings, bolts, and belt tension. He also greased the tail rotor slider. The annual condition inspection was signed off on the day of the accident. The maintenance manual for the helicopter recommends that the tail rotor belts be replaced every 250 hours, every 2 years, or as needed upon condition inspections, whichever comes first. All three tail rotor belts were replaced in January 2006 and the center tail rotor belt was replaced in September 2006. There is no indication in the tail rotor maintenance records that any of the tail rotor belts were replaced after 2006. The operator reported that before the accident the belts appeared to be in satisfactory condition but acknowledged they were beyond the 2-year service life and should have been replaced. ## Aircraft - Registration: [N314AC](https://openairdocs.org/deregistered/N314AC-2025-04-21), registration cancelled 2025-04-21, S/N 1961, built 2003 (OpenAirDocs) - Reported make and model: ROTORWAY EXEC (90) - Registry model: [Colbert Anthony Brian COLBERT/EXEC](https://openairdocs.org/model/colbert-anthony-brian-colbert-exec) (registry code 056148K) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Helicopter, amateur-built - Serial number: 1961 - Year built: 2004 - Airframe hours: 232 - Engines: Rotorway International RW 162 150 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Rutherford Stephen M - Registered owner: Rutherford Stephen M - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, October 11, 2024 - Departed: C65, Plymouth, IN - Airport: C65, Plymouth Municipal - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; injuries: minor; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: helicopter, airplane; medical: class 3, without waivers/limitations; last flight review April 17, 2023; seat: left; restraint: 4-point; flight hours: 3,457 total, 2 in this make and model, 2,818 as pilot in command, 18 in the last 90 days, 9 in the last 30 days, 2 in the last 24 hours - Flight instructor; age 56; injuries: minor; flight instructor, commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review June 23, 2023; seat: right; restraint: 4-point; flight hours: 3,930 total, 320 in this make and model, 3,865 as pilot in command, 91 in the last 90 days, 37 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 81 °F, dew point 45 °F - Altimeter: 30.04 inHg - Observed at: KC65, 5 nm away - METAR: KC65 112055Z AUTO 23009KT 10SM CLR 27/07 A3004 ## 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 20241011016869A](https://openairdocs.org/incident/20241011016869A), Oct 11, 2024: Colbert Anthony Brian COLBERT/EXEC, Plymouth, IN, Substantial damage. On October 11, 2024, at 1630 local time, an experimental rotorway exec 90 helicopter, [privacy data omitted], [privacy data omitted] flown by a commercial… ## Docket (5 files) The files NTSB released with the investigation on April 2, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=195315. 4.2 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18112823&FileExtension=pdf&FileName=6120_1_Redacted-Rel.pdf - Photos (item 2, PDF, 4 pages, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18446052&FileExtension=pdf&FileName=Photos-Rel.pdf - Maintenance records (item 3, PDF, 2 pages, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18113213&FileExtension=pdf&FileName=Maintenance%20Logs_Redacted-Rel.pdf - Recommended maintenance (item 4, PDF, 1 page, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18112916&FileExtension=pdf&FileName=Tail%20Rotor%20Maintenance-Rel.pdf - Memorandum for record a�� email, owner (item 5, PDF, 1 page, 62 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18113290&FileExtension=pdf&FileName=MOR%20-%20Owner-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.