Pilot Debrief

BURNS Mini 500 near Butler, MO — 2015-08-21

Final reportCEN15LA396
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Date
2015-08-21
Location
Butler, MO, USA
Airport
BUM
Aircraft
BURNS Mini 500
Registration
UNREG
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

The pilot's failure to attain a proper landing flare following an autorotation for reasons that could not be determined based on available information.

NTSB narrative

The private pilot had just departed the airport in the unregistered, amateur-built helicopter. While in the traffic pattern, the helicopter shuddered and made a noise the pilot described as sounding like a tire blowing out on a car. He performed an autorotation to a soybean field and leveled the helicopter at 5 ft above the ground (2 ft above the crop), although he stated that he believed that the helicopter's tail rotor may have been in the crop, which caused instability. When the rotor speed bled off, the helicopter settled onto its right skid and rolled over. Postaccident examination did not reveal any preimpact anomalies, but a complete examination was not performed. Although the pilot believed that the one-way clutch, part of the power transmission system of the helicopter, had failed, which would have resulted in a loss of power to the rotor system, he had not disassembled the transmission to verify this. Additionally, the pilot's improper flare during the autorotation resulted in a premature loss of rotor speed, and the subsequent rollover.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have conducted a thorough preflight inspection to identify potential issues.

NTSB coding

Evidence available

  • 2 docket documents
View NTSB final reportView NTSB docket

Docket documents2

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