Amateur-built EXEC accident near Plymouth, Indiana, October 11, 2024
On October 11, 2024 at about 8:50 pm local time, a 2004 amateur-built EXEC (helicopter), registered N314AC, was substantially damaged in an accident during approach (VFR pattern base) near Plymouth, Indiana (Plymouth Municipal airport). It was an instructional flight under general aviation rules (Part 91). 2 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 11, 2024 · about 8:50 pm local time
- Place
- Plymouth, Indiana · Plymouth Municipal · map
- Type
- Accident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built EXEC 90, built 2004
- Registration
- N314AC · no longer on the register · serial 1961
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Autorotation Collision with terrain or object (not controlled flight into terrain)
- Aircraft maintenance event during prior to flight
- Sys/Comp malf/fail (non-power) during approach (VFR pattern base) defining event
The NTSB's findings
- Aircraft › Aircraft handling/service › Maintenance/inspections › Time limits › Incorrect service/maintenance
- Aircraft › Aircraft propeller/rotor › Tail rotor › (general) › Failure
- Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Directional control › Attain/maintain not possible
- Personnel issues › Action/decision › Action › Lack of action › Maintenance personnel
- Personnel issues › Task performance › Maintenance › Replacement › Owner/builder
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: airplane single-engine; instructor: helicopter; instructor: instrument airplane; instrument: airplane; instrument: helicopter; rotorcraft: gyroplane; rotorcraft: helicopter
- Flight time: 3,457 hours in all; 2 in this make and model; 18 in the last 90 days; 9 in the last 30 days; 2,818 as pilot in command; 765 on instruments
- Last flight review: April 17, 2023
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: left
- Injury: minor injuries
Flight instructor
- Certificate: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: helicopter; rotorcraft: helicopter
- Flight time: 3,930 hours in all; 320 in this make and model; 91 in the last 90 days; 37 in the last 30 days; 3,865 as pilot in command; 2,520 on instruments
- Last flight review: June 23, 2023
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: minor injuries
The aircraft
- Airframe total time: 232 hours
- Last inspection: condition inspection, October 11, 2024
- Maximum gross weight: 1,500 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotorway International RW 162 (piston); 232 hours total
The flight
- Departed from: C65 Plymouth IN at 8:20 pm
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 230° at 9 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 81°F (27°C), dew point 45°F (7°C)
- Altimeter: 30.04 inHg
- Observation at 4:55 pm from KC65, 5 miles away
Weather report (METAR): KC65 112055Z AUTO 23009KT 10SM CLR 27/07 A3004
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
Photographs from the investigation 3 pictures from the NTSB's docket, as the NTSB released them
Photograph 1 – Accident helicopter in cornfield
Photograph 2 – Broken tail rotor belt
Photograph 3 – Frayed tail rotor beltThe NTSB's photographs with the NTSB's captions, at screen size. Open a picture to see it full size or to report one that should not be shown.
Documents from the investigation the NTSB's docket: the evidence folder behind the report
5 documents, released by the NTSB on April 2, 2025. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 10 pages | View Download |
| 2 | Photos | PDF, 4 pages · our copy | View Download |
| 3 | Maintenance Records | PDF, 2 pages | View Download |
| 4 | Recommended Maintenance | PDF, 1 page | View Download |
| 5 | Memorandum for Record A�� Email, Owner | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.