Hiller UH-12ET accident near Williams, California, June 30, 1999
On June 30, 1999 at about 2:00 pm local time, a Hiller UH-12ET (helicopter), registered N7173F, was substantially damaged in an accident near Williams, California. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 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 pilot's inadequate preflight planning and verification that fuel was available for the intended flight. A factor was the fuel quantity false indication.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 30, 1999 · about 2:00 pm local time
- Place
- Williams, California · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Hiller UH-12ET · all UH-12ETs on the register
- Registration
- N7173F · registry record · serial 2011
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
While spraying a rice field the engine suddenly quit. The pilot force landed in the field severing the tail boom. The pilot reported the turbine powered helicopter had been fueled the day before the accident, however, he did not visually confirm it. The aircraft had only flown 0.5 hours during this flight. Examination of the fuel system revealed a broken wire in the fuel quantity indicating system. According to the maintenance manual for this helicopter, the open circuit caused by the wire breakage will cause a fuel quantity indication of 34 gallons when the tank is empty.
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: 18,000 hours in all
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 12,083 hours
- Last inspection: inspection type not recorded
- Maximum gross weight: 3,100 lb
- Seats: 1
- Landing gear: fixed
- Engine: Allison 250-C20B (turboshaft); 0 hours total
- Operator: Pacific Valley Aviation
The flight
- Departed from: NONE Colusa CA at 1:30 pm
- Destination: NONE CA
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 20 statute miles
- Sky: clear
- Temperature: 79°F (26°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.