Pilot Debrief

EUROCOPTER AS-350-BA near Linden, NJ — 2008-09-19

Final reportMIA08LA199
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Date
2008-09-19
Location
Linden, NJ, USA
Airport
LDJ
Aircraft
EUROCOPTER AS-350-BA
Registration
N906BA
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Maneuvering

Probable cause

The flight instructor’s delayed remedial action (flight control inputs) during a practice autorotation/run-on landing resulting in fracture damage to the main rotor system Starflex.

NTSB narrative

The flight instructor was monitoring the student pilot during a 180-degree autorotation as part of the flight training. The maneuver was entered at 700 feet above the ground and at 100 knots. Once the intended spot was made for the 'power-on' recovery, the flare was started. As the flight instructor advanced the fuel flow control valve into the flight position, the helicopter started to settle and the low rotor speed horn came on. The flight instructor took over the controls advising the student pilot that it was going to be a run-on landing. During the landing, while in the ground run, the nose of the helicopter pitched forward as the skids dug into the mud. The flight instructor pulled back on the cyclic to prevent the blades from contacting the ground. The helicopter came to rest in the upright position in the grassy area. Post accident inspection of the helicopter’s main rotor system revealed that the 2,167 hours time in service Starflex component had two of its three arms fractured. Examinations of the fracture surfaces revealed no indications of any pre-existing damage to the areas. The fractures were consistent with overstress and unusual loads, which were produced during abrupt flight control inputs with low main rotor RPM.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Instructor could have aborted the maneuver before low rotor speed occurred.

NTSB coding

Evidence available

  • 7 docket documents
View NTSB final reportView NTSB docket

Docket documents7

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