Hiller UH-12B accident near Rio Vista, Texas, September 19, 2012
On September 19, 2012 at about 3:45 pm local time, a Hiller UH-12B (helicopter), registered N94735, was substantially damaged in an accident during maneuvering (low-alt flying) near Rio Vista, Texas. It was a personal flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The catastrophic failure and disintegration of the No. 6 engine piston, which resulted in a total loss of engine power.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 19, 2012 · about 3:45 pm local time
- Place
- Rio Vista, Texas · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Hiller UH-12B · all UH-12Bs on the register
- Registration
- N94735 · registry record · serial 523
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that he was on a survey flight when the helicopter engine suddenly stopped; he elected to autorotate to a field. The area he landed in had high vegetation, which “grabbed” the helicopter skids and the helicopter impacted the ground hard. Examination of the helicopter revealed that the main rotor impacted the tailboom during the accident and the tail rotor had separated from the helicopter. Examination of the engine revealed the No. 6 piston had disintegrated catastrophically, which caused additional internal damage to the engine.
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
- Powerplant sys/comp malf/fail during maneuvering (low-alt flying)
- Loss of engine power (total) during maneuvering (low-alt flying) defining event
- Autorotation Off-field or emergency landing
The NTSB's findings
- cause Aircraft › Aircraft power plant › Power plant › (general) › Failure
Dual student
- Certificate: student
- Ratings: rotorcraft: helicopter
- Medical certificate: Class 3 (with waivers/limitations)
- Injury: no injuries
The aircraft
- Last inspection: annual inspection
- Seats: 4
- Landing gear: fixed
- Engine: Franklin 6A4200 SERIES (piston); 0 hours total
The flight
- Departed from: Rio Vista TX
- Destination: Rio Vista TX
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 150° at 9 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 73°F (23°C), dew point 57°F (14°C)
- Altimeter: 30.18 inHg
- Observation at 3:55 pm from KCPT
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight 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.