Finke ROTORWAY EXEC 162F N103RW

Summary

On 21 July 2004 at about 22:40 local time, a Finke ROTORWAY EXEC 162F registered N103RW was involved in an accident near Cameron Park, California, United States. One person was on board and one died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

21 July 2004 at 22:40

Classification

Accident

Location

Cameron Park, California, United States

Nearest airport

Cameron Airpark (O61)

Coordinates

38.6683, -120.9800

Aircraft

Finke ROTORWAY EXEC 162F

Registration

N103RW

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Flight Test

Phase of flight

Not recorded

Route

Cameron Park → Unknown

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

LAX04LA274

1 person died.

The owner-builder's improper main rotor blade (MRB) maintenance/installation by under torquing the blade retaining nut.

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

Read the full NTSB narrative

Witnesses said the helicopter was in cruise flight when it pitched up, rolled left to an inverted attitude while portions of the airframe separated, then it descended straight down to ground impact. Wreckage examination found evidence that the main rotor blades (MRB) diverged from their plane of rotation, and mast bumping occurred. Thereafter, the blades impacted the tail boom, which separated from the helicopter. The helicopter became uncontrollable, rolled inverted, and descended into a residence. Portions of both the helicopter and residence were consumed in the post impact fire. The pilot-builder held a repairman certificate for his experimental category helicopter. The pilot had replaced RotorWay's main rotor blades with blades manufactured by another company. During assembly of the helicopter, each MRB was attached to its respective blade yoke with a single retention nut/bolt assembly. The subsequent wreckage examination revealed that the nut that secured one of the MRBs to its retention bolt was missing. The retention bolt was examined, and its threads were not stripped; the bolt was intact. During the MRB installation, the nut had likely been inadequately torqued, and thereafter, it had worked off the bolt during flight. With the bolt loose, the MRB was free to diverge from its normal rotation plane, thus rendering the helicopter uncontrollable.

Quoted verbatim from the NTSB record.