Hiller UH-12E accident near Granby, New York, May 29, 1997
On May 29, 1997 at about 1:20 pm local time, a Hiller UH-12E (helicopter), registered N4029S, was substantially damaged in an accident near Granby, New York. It was a positioning flight under agricultural flying rules (Part 137). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
failure of the pilot/owner to replace the torsional clutch as specified by the manufacturer, and subsequent failure of the helicopter's clutch, which resulted in a forced landing (autorotation). A related factor was: the encounter with trees in the emergency landing area.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 29, 1997 · about 1:20 pm local time
- Place
- Granby, New York · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Hiller UH-12E · all UH-12Es on the register
- Registration
- N4029S · registry record · serial 5129
- Damage
- Substantial damage
- Flight
- Positioning flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
The pilot/owner had completed an uneventful aerial application flight, and he began to reposition the helicopter to another site. En route, at 500 feet AGL, the helicopter's engine began to overspeed. The pilot entered autorotation, and the helicopter struck trees and landed hard. Examination revealed the elastomeric torsional coupling inside the transmission, and the secondary steel drive flanges were sheared. The manufacturer's service data for the coupling stated that mandatory replacement of the coupling should occur at 5,000 hours or 5 years from the date embossed on the rubber, or in accordance with maintenance requirements for the coupling, which ever occurred first. The raised numbers on the coupling indicated a date of May 1988, 9 years before 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
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; rotorcraft: helicopter
- Flight time: 10,000 hours in all; 3,600 in this make and model; 10,000 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: ctr
The aircraft
- Airframe total time: 6,440 hours
- Last inspection: 100-hour inspection, May 13, 1997; 2 hours since
- Maximum gross weight: 3,100 lb
- Seats: 1
- Landing gear: fixed
- Engine: Lycoming VO-540-C2A (piston); 0 hours total
The flight
- Departed from: NONE Fulton NY at 12:15 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: broken clouds at 25,000 ft; scat at 18,000 ft
- Temperature: 68°F (20°C), dew point 50°F (10°C)
- Altimeter: 30.00 inHg
- Observation at 1:50 pm from SYR, 19 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
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.
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.