Hiller UH-12C accident near Plant City, Florida, April 27, 2007
On April 27, 2007 at about 5:45 pm local time, a Hiller UH-12C (helicopter), registered N92993, was substantially damaged in an accident near Plant City, Florida. It was an instructional flight under general aviation rules (Part 91). 1 person was seriously injured; 1 other was unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The loss of engine power due to a magneto impulse coupling failure for undetermined reasons.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 27, 2007 · about 5:45 pm local time
- Place
- Plant City, Florida · map
- Type
- Accident
- Injuries
- 1 person was seriously injured; 1 other was unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Hiller UH-12C · all UH-12Cs on the register
- Registration
- N92993 · no longer on the register · serial 852
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The flight instructor stated that he was conducting a discovery flight with a student, and all of a sudden, while the helicopter was in cruise flight at an altitude of 600 feet, the engine shook violently, shaking the whole helicopter. He said this lasted for several seconds and then the engine ceased operating. He said he immediately entered autorotation and attempted to affect an autorotative landing. During the landing the helicopter incurred damage. A postcrash examination of the helicopter by an FAA licensed airframe and powerplant mechanic, under the supervision of an FAA airworthiness inspector revealed that the right magneto impulse coupling had failed, and caused the impulse coupling to impact the stud used for starting. According to the inspector, this resulted in the gear train stoppage, and the engine ceasing to operate. The maintenance log revealed that the helicopter had last been given an annual inspection on June 5, 2006.
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: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 1,085 in this make and model
- Last flight review: February 1, 2006
- Medical certificate: Class 2
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 701 hours
- Last inspection: annual inspection, June 1, 2006
- Maximum gross weight: 2,500 lb
- Seats: 3
- Landing gear: fixed
- Engine: Franklin 6V335 (piston); 0 hours total
The flight
- Departed from: VDF Tampa FL at 5:00 pm
- Destination: VDF
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 260° at 13 knots, gusting 19
- Visibility: 10 statute miles
- Sky: scat at 4,100 ft
- Temperature: 90°F (32°C), dew point 68°F (20°C)
- Altimeter: 30.05 inHg
- Observation at 6:00 pm from PCM
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | 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.