Amateur-built BABY BELLE accident near Stuart, Iowa, September 12, 2015
On September 12, 2015 at about 4:30 pm local time, a 2001 amateur-built BABY BELLE (helicopter), registered N135PA, was substantially damaged in an accident during maneuvering near Stuart, Iowa. It was a personal flight under general aviation rules (Part 91). 1 person had minor injuries; 1 other was unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of the tail rotor driveshaft for reasons that could not be determined due to the mechanically and thermally deformed fracture surface.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 12, 2015 · about 4:30 pm local time
- Place
- Stuart, Iowa · map
- Type
- Accident
- Injuries
- 1 person had minor injuries; 1 other was unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built BABY BELLE, built 2001
- Registration
- N135PA · no longer on the register · serial 0412N
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The private pilot was conducting a personal flight in the experimental, amateur-built helicopter. The pilot reported that, while he was maneuvering the helicopter about 400 ft above ground level, it yawed left, then suddenly "snapped" right, and then began spinning. The pilot attempted to regain control of the helicopter and was able to briefly stop the spin, but the spin then continued. The pilot subsequently conducted a forced landing to a cornfield, during which the helicopter impacted terrain and rolled over. Examination of the helicopter revealed that the tail rotor driveshaft had failed during the flight, which resulted in a loss of control. The fracture surface of the driveshaft was mechanically and thermally deformed, and the failure mode could not be established. The pilot's medical and flight review were not current; however, the pilot's actions were not a contributing factor in the accident.
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
- Flight control sys malf/fail during maneuvering defining event
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Tail rotor drive system › Tail rotor drive shaft › Failure
- cause Not determined › Not determined › (general) › (general) › Unknown/Not determined
Pilot
- Certificate: private
- Ratings: rotorcraft: helicopter
- Flight time: 350 hours in all; 242 in this make and model; 310 as pilot in command
- Medical certificate: Class 3
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 242 hours
- Last inspection: condition inspection, January 15, 2015; 4 hours since
- Maximum gross weight: 1,500 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O&VO-360 SER (piston); 0 hours total
The flight
- Departed from: Guthrie IA at 3:45 pm
- Destination: Stuart IA
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 61°F (16°C), dew point 50°F (10°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
4 documents, released by the NTSB on July 5, 2016. 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 | NTSB Materials Laboratory Report | PDF, 4 pages | View Download |
| 3 | Excerpts of Maintenance Records | PDF, 4 pages | View Download |
| 4 | Photo | 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.