Pilot Debrief

ROBINSON HELICOPTER CO R66 near Philip, SD — 2011-10-01

Final reportCEN12FA001
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Date
2011-10-01
Location
Philip, SD, USA
Aircraft
ROBINSON HELICOPTER CO R66
Registration
N266CY
Category
Helicopter
Highest injury
Fatal
Fatalities
1
Phase of flight
Cruise

Probable cause

The in-flight separation of the main rotor mast following a mast bumping event. The reason for the mast bumping event could not be determined due to postaccident damage.

NTSB narrative

The helicopter was on a cross-country flight when it experienced a separation of the main rotor mast 8 inches below the teeter bolt, and the main rotor blade assembly separated from the flying helicopter. Subsequently, the helicopter impacted terrain and a postimpact fire ensued. Examination of the mast revealed fracture features consistent with overload failure and mechanical damage indicative of mast bumping. An examination of the airframe, engine, and remaining systems revealed no preimpact anomalies. The reason for the mast bumping event could not be determined due to the amount of thermal damage to the wreckage.

Analysis

Primary failure mode
Loss of control
First missed decision gate
Pilot could have chosen to land or divert after fuel inquiry.

NTSB coding

Evidence available

  • FDR / data
  • Photos
  • 19 docket documents
View NTSB final reportView NTSB docket

Docket documents19

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