Eurocopter EC120B accident near Goshen, Indiana, November 16, 2015
On November 16, 2015 at about 3:40 pm local time, a 2010 Eurocopter EC120B (helicopter), registered N88HA, was substantially damaged in an accident during enroute (cruise) near Goshen, Indiana (Goshen Municipal airport). It was an instructional flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of the Thomas coupling at the interface with the main gear box tail rotor output shaft, which resulted in the helicopter's loss of tail rotor control.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 16, 2015 · about 3:40 pm local time
- Place
- Goshen, Indiana · Goshen Municipal · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Eurocopter EC120B B, built 2010 · all EC120Bs on the register
- Registration
- N88HA · registry record · serial 1634
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The flight instructor and helicopter-rated pilot were returning from an instructional flight in the helicopter. The flight instructor reported they heard a noise come from somewhere in the helicopter. They diverted to a nearby airport for a precautionary landing. As they approached the airport, the noise level increased. The instructor took the controls, and, about 15 ft above ground level and 25 knots, the helicopter began an uncommanded left yaw. The instructor responded with corresponding right pedal input; however, it did not stop the left yaw. The instructor immediately reduced engine power and initiated a hovering autorotation. A postaccident examination revealed the tail rotor drive system's Thomas coupling interface with the main gear box tail rotor output shaft failed. The Thomas coupling was part of the installation of an after-market air conditioning system approved under a supplemental type certificate (STC). Laboratory examinations revealed that while the pulley within the tail rotor drive system was made to the STC holder's requirements, those requirements deviated significantly from the original equipment output flange. Changes were made to the spline profile, manufacturing method, and lubrication regimen. Any of these changes, either independently or collectively, likely contributed to the increased wear and failure of the Thomas coupling. After the accident, the manufacturer issued a service bulletin and the Federal Aviation Administration issued an emergency airworthiness directive that called for an immediate and repetitive inspection of the coupling every 25 flight hours or deactivating the air conditioning system by removing the STC's Thomas coupling and reinstalling the original equipment manufacturer's Thomas coupling half.
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
- Sys/Comp malf/fail (non-power) during enroute (cruise) defining event
- Loss of tail rotor effectiveness during enroute (cruise)
- Autorotation Off-field or emergency landing
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Tail rotor drive system › Tail rotor drive shaft › Fatigue/wear/corrosion
- factor Personnel issues › Task performance › Maintenance › Modification/alteration › Other/unknown
Pilot
- Certificate: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane; rotorcraft: helicopter
- Flight time: 5,100 hours in all; 112 in this make and model
- Last flight review: October 28, 2015
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
Flight instructor
- Certificate: airline transport pilot, flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 11,200 hours in all; 750 in this make and model
- Last flight review: October 30, 2015
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 320 hours
- Last inspection: annual inspection, May 6, 2015
- Maximum gross weight: 6,561 lb
- Seats: 5
- Landing gear: fixed
- Engine: Arrius 2F (turboshaft); 309 hours total
- Operator: Hanscopter LLC
The flight
- Departed from: EKM Elkhart IN at 3:00 pm
- Destination: EKM Elkhart IN
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 160° at 8 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 54°F (12°C), dew point 34°F (1°C)
- Altimeter: 30.22 inHg
- Observation at 3:53 pm from GSH
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N88HA the same tail number, which may have belonged to a different aircraft at the time
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.