Pilot Debrief

Bell 47G near Atoka, TN — 2020-06-15

Final reportERA20LA216
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Date
2020-06-15
Location
Atoka, TN, USA
Airport
59TN
Aircraft
Bell 47G
Registration
N473TT
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Descent

Probable cause

A total loss of engine power due to a blocked fuel line; the reason for the blockage could not be determined based on the available evidence.

NTSB narrative

The pilot had conducted eight brief (7- to 8-minute) nonrevenue passenger flights uneventfully on the day of the accident. The helicopter was fueled before the eighth flight. During the ninth flight, the helicopter’s engine lost total power when the helicopter was about 1.5 miles north of the heliport and was descending through an altitude of 900 ft mean sea level. The pilot executed an autorotation and landed in a field. On touchdown, the main rotor blade struck the tailboom. Postaccident examination of the airframe and engine revealed no evidence of any preimpact malfunctions except for the fuel line to the carburetor, which had collapsed. A borsescope inspection revealed that light could not be observed through the fuel line. The borescope was then pushed through the fuel line, and no contaminates were found. A subsequent metallurgical examination of the fuel line revealed no blockages; no damage to the interior of the hose; and no evidence of kinks, creases, or material creep. The blocked fuel line likely resulted in the loss of engine power; however, the reason for the blockage could not be determined.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have checked fuel line integrity before flight.

NTSB coding

Evidence available

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

Docket documents6

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