Pilot Debrief

Enstrom F28 near Danbury, TX — 2019-12-31

Final reportCEN20LA051
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Date
2019-12-31
Location
Danbury, TX, USA
Airport
07TA
Aircraft
Enstrom F28
Registration
N57SJ
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Maneuvering

Probable cause

The failure of the engine's No.3 intake valve resulting is a loss of engine power and a rollover following the autorotation to soft ground.

NTSB narrative

The student pilot turned the helicopter onto the crosswind leg of the traffic pattern during a training flight when the engine suddenly began to run rough and lost partial power. The flight instructor took the controls and executed an autorotation into a clearing. The skids of the helicopter sank into the soft mud, the rotor blades contacted the ground, and the helicopter rolled onto its side. Examination of the engine revealed that a portion of the No. 3 cylinder intake valve had broken off and migrated into the No. 1 cylinder, where it lodged between the No. 1 cylinder's intake valve and seat, holding that valve in the open position and resulting in the partial loss of engine power.

Analysis

Primary failure mode
Engine power loss

NTSB coding

Evidence available

  • 2 docket documents
View NTSB final reportView NTSB docket

Docket documents2

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