Bell OH-58A accident near Huron, California, April 9, 1998
On April 9, 1998 at about 6:00 am local time, a Bell OH-58A (helicopter), registered N176SJ, was substantially damaged in an accident near Huron, 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
A loss of engine power due to deteriorated O-ring seals in the fuel boost pump, which allowed air to enter the fuel lines. Factors in the accident were the inadequate manufacturer's inspection criteria for the fuel boost pump O-ring seals and the resulting failure of the operator's maintenance personnel failure to detect the condition.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 9, 1998 · about 6:00 am local time
- Place
- Huron, California · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell OH-58A · all OH-58As on the register
- Registration
- N176SJ · registry record · serial 70-15556
- 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 the initial climb, the pilot noted that the fuel boost pump warning light had flickered on and then off, with a corresponding surge in the engine. Approximately 20 feet agl, engine power was lost and the helicopter impacted the ground. A functional field check of the fuel system was conducted and it was noted that there was a leak in the breakaway valve, which would have allowed air to enter the system. Further examination of the fuel boost pump and breakaway valve revealed that the O-rings were deteriorated. The field inspection further revealed that the inlet shutoff valve arm on the fuel boost pump was bent. According to the manufacturer's overhaul manual, if the inlet shutoff valve arm is bent it may prevent the valve from opening and restrict the fuel flow. According to the component overhaul manuals, the O-ring seals in both the fuel boost pump and the fuel breakaway valve are not required to be inspected during routine inspections and are replaced as on-condition items. A hydro leakage test and performance flow test check was conducted on the fuel boost pump with the original O-rings. The fuel boost pump did not pass the manufacturer's tests. The O-ring seals were replaced with new ones, and the fuel boost pump functioned within manufacturer's limits. The fuel control unit and fuel pump were tested and no discrepancies were found. The fuel nozzle was also tested and flowed within manufacturer's limits. Maintenance records disclosed that the last time the fuel boost pump was worked on was 5 years prior to the accident.
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: flight instructor, commercial pilot
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 3,000 hours in all; 125 in this make and model; 260 in the last 90 days; 100 in the last 30 days; 2,800 as pilot in command; 1,250 on instruments
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 2,518 hours
- Last inspection: continuous airworthiness programme, April 5, 1998; 13 hours since
- Maximum gross weight: 3,200 lb
- Seats: 2
- Landing gear: fixed
- Engine: Allison T63-A720 (turboshaft); 0 hours total
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: night, bright
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 54°F (12°C), dew point 45°F (7°C)
- Altimeter: 30.00 inHg
- Observation at 5:56 am from FAT, 20 miles away
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.
Other NTSB records under N176SJ 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.