Hiller UH-12E accident near Helm, California, September 10, 1988
On September 10, 1988 at about 11:30 pm local time, a Hiller UH-12E (helicopter), registered N4029Y, was substantially damaged in an accident near Helm, 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
- September 10, 1988 · about 11:30 pm local time
- Place
- Helm, 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
- N4029Y · no longer on the register · serial 5135
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
DURING AN AERIAL APPLICATION FLIGHT, THE PILOT LOST CONTROL OF THE HELICOPTER JUST AFTER LIFTOFF AND COLLIDED WITH THE TERRAIN. INSPECTION OF THE WRECKAGE REVEALED THAT THE CHEMICAL TRUCKS FILLER HOSE WAS STILL ATTACHED TO THE HELICOPTER WHEN IT LIFTED OFF.
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: single-engine land; rotorcraft: helicopter
- Flight time: 5,500 hours in all; 3,500 in this make and model; 120 in the last 90 days; 40 in the last 30 days; 5,000 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: ctr
The aircraft
- Airframe total time: 3,005 hours
- Last inspection: 100-hour inspection, September 1, 1988; 47 hours since
- Maximum gross weight: 2,750 lb
- Seats: 3
- Landing gear: retractable
- Engine: Lycoming VO-540-C2A (piston); 0 hours total
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 310° at 3 knots, gusting 5
- Visibility: 15 statute miles
- Sky: clear
- Temperature: 84°F (29°C), dew point 0°F (-18°C)
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.