Pilot Debrief

Aerospatiale AS350 near Montgomery, TX — 2019-03-27

Final reportCEN19FA109
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Date
2019-03-27
Location
Montgomery, TX, USA
Aircraft
Aerospatiale AS350
Registration
N818MC
Category
Helicopter
Highest injury
Fatal
Fatalities
1
Phase of flight
Cruise

Probable cause

Maintenance personnel's failure to properly re-install and secure a fuel line, which resulted in a total loss of engine power.

NTSB narrative

While conducting controlled fire operations, the helicopter was maneuvering over trees, when the engine lost power. The pilot performed an autorotation and the helicopter impacted trees and then terrain, and came to rest on its side. The fuselage and empennage sustained substantial damage. One crewmember was fatally injured. Examination revealed that a fuel line between the engine firewall and hydro-mechanical unit (HMU) was loose and not secured with safety wire as required. About 25 flight hours before the accident, that fuel line was disconnected to defuel of the helicopter in order to perform a weight and balance check. No other maintenance was performed in that area. The mechanic who returned the helicopter to service stated that he was confident that he torqued and secured the line. No other anomalies were detected with the helicopter which would have precluded normal flight. The circumstances of the accident are consistent with a loss of engine power due to the loose fuel line.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot reported fuel pressure light flickered but did not investigate further.

NTSB coding

Evidence available

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

Docket documents6

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