Hiller UH-12E accident near Thermal, California, August 17, 1988
On August 17, 1988 at about 3:05 am local time, a Hiller UH-12E (helicopter), registered N65120, was substantially damaged in an accident near Thermal, California. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this accident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 17, 1988 · about 3:05 am local time
- Place
- Thermal, California · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Hiller UH-12E · all UH-12Es on the register
- Registration
- N65120 · no longer on the register · serial 1469
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
SHORTLY AFTER REFUELING THE HELICOPTER & RELOADING THE HOPPER, THE PLT TOOK OFF & WAS STARTING TO SPRAY A FIELD WHEN THE ENG SUDDENLY LOST POWER. THE PLT SAID THE HELICOPTER WAS DSCNDG FROM ABOUT 30 FT WHEN THE POWER LOSS OCCURRED; THUS, HE BARELY HAD TIME TO TAKE CORRECTIVE ACTION. THE HELICOPTER TOUCHED DOWN IN AN UPRIGHT ATTITUDE, BUT IT SKIDDED INTO A 1 FT BERM, ROLLED OVER & CAME TO REST IN A MUDDY/FLOODED FIELD. MUD & WATER WERE FOUND IN THE ACFT FUEL SYSTEM. THE EVIDENCE INDICATED THAT THE FUEL CONTAMINATION WAS NOT THE RESULT OF IMPACT & INVERSION. A CHECK OF THE MOBILE REFUELING UNIT REVEALED IT CONTAINED CRACKS WHICH ALLOWED MOISTURE & OTHER CONTAMINANTS TO ENTER. ALSO, THE MOBILE UNIT'S FUEL FILTER WAS IMPROPERLY INSTALLED & WAS NOT REMOVING CONTAMINANTS FROM THE FUEL.
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; multi-engine sea; single-engine land; instructor: helicopter; instrument: airplane; rotorcraft: helicopter
- Flight time: 13,000 hours in all; 3,500 in this make and model; 60 in the last 90 days; 20 in the last 30 days; 12,000 as pilot in command; 200 on instruments
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: ctr
The aircraft
- Airframe total time: 2,340 hours
- Last inspection: annual inspection, May 2, 1988; 42 hours since
- Maximum gross weight: 3,100 lb
- Seats: 1
- Landing gear: fixed
- Engine: Lycoming VO-540-C2A (piston); 0 hours total
- Operator: West Farm Air, INC
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: dusk
- Visibility: 30 statute miles
- Sky: clear
- Temperature: 90°F (32°C), dew point 45°F (7°C)
- Altimeter: 29.00 inHg
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.