Pilot Debrief

EUROCOPTER AS 350 B2 near Seattle, WA — 2012-05-22

Final reportWPR12IA248
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Date
2012-05-22
Location
Seattle, WA, USA
Airport
BFI
Aircraft
EUROCOPTER AS 350 B2
Registration
N105TV
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Maneuvering

Probable cause

Failure of maintenance personnel to ensure that the tail rotor pitch change link bolt was properly secured, which resulted in an in-flight separation of the bolt and subsequent vibration.

NTSB narrative

The pilot reported that he had just entered a slow orbit when the helicopter experienced what he described as a severe vibration. The vibration was continuous and so severe that the pilot diverted to a nearby airport and landed. Postincident examination of the helicopter revealed that one of the tail rotor pitch change link bolts (to the pitch arm) was missing. The incident flight followed a 100-hour maintenance inspection that concluded earlier that day. The inspection included maintenance and service to the tail rotor assembly. The pilot reported that the pitch change link bolt (to pitch arm) was not correctly tightened and secured while in maintenance and subsequently loosened and released during the flight.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Ensure proper tightening of tail rotor components during maintenance.

NTSB coding

  • Flight control sys malf/fail · Maneuvering
  • Maintenance

Evidence available

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

Docket documents3

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