Hiller UH 12E accident near Chowchilla, California, December 9, 2013
On December 9, 2013 at about 2:30 pm local time, a 1978 Hiller UH 12E (helicopter), registered N36MV, was substantially damaged in an accident during maneuvering (low-alt flying) near Chowchilla, California. It was an other work-use 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 failure of the torsional drive coupling, which resulted in a loss of drive to the main rotor system during low-altitude flight.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 9, 2013 · about 2:30 pm local time
- Place
- Chowchilla, California · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Hiller UH 12E, built 1978 · all UH 12Es on the register
- Registration
- N36MV · no longer on the register · serial 5060
- Damage
- Substantial damage
- Flight
- Other work-use flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot, who also owned the helicopter, reported that he was performing frost control operations over a citrus grove at low altitude when the helicopter's engine began to overspeed with an accompanying decrease in rotor speed. He initiated an autorotation, and the helicopter subsequently landed hard in an adjoining orchard. The pilot removed the helicopter from the accident site immediately following the accident and began disassembling it and sending components out for repair before it was examined. During the subsequent examination of the helicopter, both the elastomeric ring and lower drive lugs (engine side) of the main transmission torsional drive coupling were found sheared off, which would have resulted in the loss of drive to the main rotor system described by the pilot. The pilot did not make the torsional drive coupling available for followup examination and reported that he had misplaced the airplane's maintenance logbooks. The torsional drive coupling incorporated an internal set of lugs designed to provide positive drive to the transmission if the elastomeric portion of the coupling failed. The lugs had sheared off, which indicated that the elastomeric coupling had failed before the accident flight. The coupling had a finite service life but, because no maintenance records were provided for examination, it could not be determined if it was within its life limit at the time of the accident. Almost 4 years before the accident flight, the helicopter had been involved in another accident, which destroyed the main rotor blades. The pilot could not provide evidence that the coupling was replaced after that accident, and, without access to the airplane's maintenance logbooks, it could not be determined if a routine inspection of the coupling had been performed. It is possible that the coupling sustained damage during the original accident, which resulted in its ultimate failure.
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
- Aircraft maintenance event during prior to flight
- Sys/Comp malf/fail (non-power) during maneuvering (low-alt flying) defining event
- Autorotation Collision with terrain or object (not controlled flight into terrain)
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Main rotor drive › Engine/transmission coupling › Failure
- Personnel issues › Task performance › Maintenance › Scheduled/routine maintenance › Maintenance personnel
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instrument: airplane; rotorcraft: helicopter
- Flight time: 30,000 hours in all; 4,000 in this make and model; 100 in the last 90 days; 50 in the last 30 days
- Last flight review: May 1, 2012
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: minor injuries
The aircraft
- Airframe total time: 7,969 hours
- Last inspection: 100-hour inspection, September 20, 2013
- Maximum gross weight: 2,700 lb
- Landing gear: fixed
- Engine: Lycoming O540 (piston); 0 hours total
- Operator: Jeff Streeter Motor Sports INC
The flight
- Departed from: N/A Chowchilla CA at 12:00 pm
- Destination: N/A Chowchilla CA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 230° at 4 knots
- Visibility: 7 statute miles
- Sky: clear
- Temperature: 21°F (-6°C), dew point 18°F (-8°C)
- Altimeter: 30.37 inHg
- Observation at 2:53 pm from KMAE, 5 miles away
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.
Other NTSB records under N36MV 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.