Bell OH-58A N176SJ

Summary

On 9 April 1998 at about 06:00 local time, a Bell OH-58A registered N176SJ was involved in an accident near Huron, California, United States. One person was on board and one had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

9 April 1998 at 06:00

Classification

Accident

Location

Huron, California, United States

Coordinates

36.2006, -120.0905

Aircraft

Bell OH-58A

Registration

N176SJ

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Aircraft damage

Substantial

Weather

VMC

Light

Night/Bright

NTSB number

LAX98LA134

1 person had minor injuries.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.