Pilot Debrief

D & D AIRCRAFT ROTORWAY EXEC near Massillon, OH — 2011-04-23

Final reportCEN11LA305
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Date
2011-04-23
Location
Massillon, OH, USA
Aircraft
D & D AIRCRAFT ROTORWAY EXEC
Registration
N614S
Category
Helicopter
Highest injury
Minor
Fatalities
0
Phase of flight
Cruise

Probable cause

The excessive wear on the secondary shaft, from the inner bearing race, which resulted in the transmission clutch disengagement and a loss of power to the rotor system.

NTSB narrative

The pilot reported that during cruise flight the engine speed increased to a high rpm and power was no longer being transmitted to the rotor system. He initiated an autorotation to a sloping, plowed field that was soft due to recent rain. The tail struck the ground during the landing flare and the main rotor blades contacted the tailboom. Postaccident inspection of the helicopter revealed the inner race of the bearing on the secondary shaft, located above the transmission clutch, was worn into the shaft, which most likely caused the clutch to disengage. This prevented the engine power from being translated to the main rotor. The cause of the wear was undetermined, and the secondary shaft was designed by the pilot.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have conducted maintenance on the secondary shaft before the flight.

NTSB coding

Evidence available

  • 2 docket documents
View NTSB final reportView NTSB docket

Docket documents2

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