Pilot Debrief

ENSTROM 280 near Colchester, VT — 2021-07-30

Final reportERA21LA309
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Date
2021-07-30
Location
Colchester, VT, USA
Aircraft
ENSTROM 280
Registration
N36DK
Category
Helicopter
Highest injury
Serious
Fatalities
0
Phase of flight
Climb

Probable cause

An in-flight fire originating in the engine compartment near the turbocharger from a source that could not be determined, which resulted in a loss of engine power and led to an autorotation and a hard landing.

NTSB narrative

The commercial pilot reported that while enroute he smelled and then observed smoke in the cockpit. He also observed a rapidly rising exhaust gas temperature despite moving the mixture to full rich. The pilot initiated a precautionary landing during which the helicopter experienced a partial and then total loss of engine power. During the final segment of the autorotation, the helicopter impacted trees and landed hard on a causeway. Postaccident examination of the engine found significant soot and thermal damage, which precluded a determination of the specific source of the in-flight engine fire. However, one cause of the fire could be eliminated. Specifically, the heaviest area of thermal damage was located around the No. 3 cylinder near the turbocharger. The outer portion of the turbocharger displayed significant thermal damage, but the turbocharger exhaust and inlet clamps were intact and remained tightly installed with safety wires present. Therefore, leakage of exhaust gases from the turbocharger was not the cause of the in-flight fire. The external damage to the turbocharger indicated that its high temperature surfaces were possible ignition sources for an ignitable liquid, such as lubricating oil or fuel. The flexible fuel and oil lines all displayed significant thermal damage, and some were destroyed by fire. Several oil lines were located near the thermal damage in the forward left portion of the engine compartment. Therefore, lubricating oil from these lines was a possible fuel source for the fire. In addition, because the flexible fuel lines were either damaged or destroyed, fuel from these lines could not be eliminated as a source of fuel for the in-flight fire.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have returned to PGB after noticing smoke in cockpit.

NTSB coding

Evidence available

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

Docket documents9

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