Pilot Debrief

MD Helicopter Inc MD 900 near Weatherford, TX — 2008-10-08

Final reportCEN09IA003
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Date
2008-10-08
Location
Weatherford, TX, USA
Aircraft
MD Helicopter Inc MD 900
Registration
N902RN
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

The failure of the vertical stabilizer control adapter due to reverse bending fatigue.

NTSB narrative

While in cruise flight, the helicopter experienced a hard right yaw and subsequent left nose tuck. The pilot was able to regain control of the helicopter and reduce the airspeed to under 100 knots. The flight continued to its destination without further incident. An examination revealed that the vertical stabilizer control system adapter failed. Metallurgical examination revealed that the failure mode was reverse bending fatigue. The vertical stabilizer control system adapter has since been redesigned. Installation of the improved design is now required by an Airworthiness Directive.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Replace the VSCS tube adapter before the flight to prevent failure.

NTSB coding

  • Flight control sys malf/fail · Enroute-cruise

Evidence available

  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

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