Pilot Debrief

MCDONNELL DOUGLAS HELICOPTER 500N near Los Alamitos, CA — 2009-10-16

Final reportWPR10TA025
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Date
2009-10-16
Location
Los Alamitos, CA, USA
Airport
KSLI
Aircraft
MCDONNELL DOUGLAS HELICOPTER 500N
Registration
N521HB
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Landing

Probable cause

The flight instructor's delayed remedial action during the instructional autorotative landing, which resulted in a failure to maintain an adequate rotor rpm to avoid a hard landing.

NTSB narrative

The certified flight instructor (CFI) and the pilot he was instructing were practicing emergency procedures, in particular, power recovery autorotations. At 700 feet above ground level (agl), the CFI rolled the throttle off (idle) and entered the autorotation. At 50 feet agl he rolled the throttle on late, realized the ground was rapidly approaching, and decided to perform a running landing. The pilot reported that he inadvertently applied partial throttle, which did not allow the engine to regain full power. With the throttle positioned at 25 percent, the rotor rpm decayed, and when the helicopter contacted the ground, a rotor blade dipped down and struck the tail boom. The pilot stated that the helicopter and engine had no mechanical failures or malfunctions during the flight.

Analysis

Primary failure mode
Loss of control
First missed decision gate
Throttle was rolled on late during the autorotation, leading to loss of control.

NTSB coding

Evidence available

  • 1 docket document
View NTSB final reportView NTSB docket

Docket documents1

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