Pilot Debrief

GAUCHAT SAFARI near Rock Springs, AZ — 2009-05-22

Final reportWPR09LA253
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Date
2009-05-22
Location
Rock Springs, AZ, USA
Aircraft
GAUCHAT SAFARI
Registration
N147MD
Category
Helicopter
Highest injury
Fatal
Fatalities
2
Phase of flight
Initial climb

Probable cause

The separation of the main rotor head during cruise flight as a result of cyclic fatigue of the main rotor head spindle. The fatigue crack was due to an inadequate manufacturing process.

NTSB narrative

During a personal flight the experimental helicopter experienced an in-flight separation of the main rotor head. Both main rotor blades were located in opposite directions from the main wreckage. The helicopter was substantially damaged by the impact forces and the postimpact fire. Postaccident examination of the main rotor head assembly and the main rotor spindle revealed that the main rotor spindle had failed due to cyclic fatigue. The origin area was located near distinct circumferential machining marks. The manufacturer subsequently issued a mandatory inspection bulletin requiring inspection of all main rotor spindles.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Inspection of the main rotor spindle prior to flight could have prevented failure.

NTSB coding

Evidence available

  • Photos
  • 7 docket documents
View NTSB final reportView NTSB docket

Docket documents7

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