Pilot Debrief

MCDONNELL DOUGLAS HELICOPTER 369E near Newfane, VT — 2010-04-21

Final reportERA10LA238
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Date
2010-04-21
Location
Newfane, VT, USA
Aircraft
MCDONNELL DOUGLAS HELICOPTER 369E
Registration
N400MB
Category
Helicopter
Highest injury
Serious
Fatalities
0
Phase of flight
Approach

Probable cause

The pilot's inadvertent encounter with a rope while maneuvering during powerline operations for undetermined reasons.

NTSB narrative

The accident occurred during a procedure to install a hold-down block onto a pulling rope located between powerline structures. An all stop order to quit pulling the rope was reportedly given 3 to 5 minutes before the accident and confirmed by the pilot via radio before maneuvering to begin the hold-down block installation. No movement of the pulling rope was reported by personnel associated with the installation. The pilot confirmed there was adequate clearance to work and positioned the helicopter near one of the structures as the additional lineman in the helicopter installed the hold-down block. After completion, the lineman in the helicopter saw two waves in the pulling rope. The first wave missed the helicopter but the second wave contacted the main rotor blade, wrapping around the main rotor mast. The lineman jumped into the helicopter, which descended to the ground and came to rest on its left side nearly inverted. The operator reported that there was no preimpact mechanical failure or malfunction with the helicopter. No determination could be made as to the reason for the reported wave in the pulling rope.

Analysis

Primary failure mode
Human factors
First missed decision gate
Pilot should have confirmed the pull was stopped before approaching the rope.

NTSB coding

Evidence available

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

Docket documents12

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