Arrow Falcon Exporters OH-58A N9286U

Summary

On 2 February 2010 at about 22:00 local time, a Arrow Falcon Exporters OH-58A registered N9286U was involved in an accident near Escalon, California, United States. One person was on board and one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

2 February 2010 at 22:00

Classification

Accident

Location

Escalon, California, United States

Coordinates

37.7636, -120.9269

Aircraft

Arrow Falcon Exporters OH-58A

Registration

N9286U

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Positioning

Phase of flight

Not recorded

Route

Escalon → Modesto

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR10LA126

1 person was seriously injured.

A loss of engine power during cruise flight due to the fatigue failure of the pneumatic fuel-to-governor control line. Also causal was the inadequate installation of the pneumatic line by maintenance personnel, and the pilot’s decision to continue flight with a known discrepancy.

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

Read the full NTSB narrative

The pilot had reported to his mechanic prior to the accident flight that the helicopter was not producing full power, was vibrating heavily, and that the DC generator caution light had illuminated. He also reported that his work load was heavy, and that he would continue onwards to return the helicopter to its home base. Shortly after takeoff the engine lost power, the pilot performed a forced landing, and the helicopter collided with terrain. Examination of the engine revealed that a stainless steel pneumatic fuel-to-governor control line had failed at its fitting. Witness marks on the line revealed that it had been rubbing against an adjacent oil line. Additionally, the pneumatic line had been bent during installation such that its surface was in contact with the connector ferrule. Analysis of the line's fracture surface revealed indications of high cycle fatigue. The fuel controller was replaced about 26 flight hours prior to the accident; replacement of the controller would have required the removal and installation of the failed line. The engine manufacturer provided installation guidance in multiple publications, and specifically cautioned against improper installations of engine lines. Examination of the DC starter-generator revealed that it had experienced a partial mechanical failure, which was likely the reason the pilot felt a vibration and observed a dc generator caution light. During the investigation the failed line was replaced, and the engine was successfully run in a test cell throughout its power range.

Quoted verbatim from the NTSB record.