NTSB Identification: CEN10CA352
14 CFR Part 91: General Aviation
Accident occurred Saturday, June 26, 2010 in Lake Charles, LA
Probable Cause Approval Date: 12/20/2010
Aircraft: AEROSPATIALE AS350, registration: N191EH
Injuries: 2 Uninjured.

NTSB investigators used data provided by various entities, including, but not limited to, the Federal Aviation Administration and/or the operator and did not travel in support of this investigation to prepare this aircraft accident report.

The flight instructor was preparing the commercial-rated pilot for a check ride in the helicopter equipped with skid-type landing gear. During one of three running landings to a touchdown, the flight instructor was demonstrating a practice hydraulic failure running landing and the helicopter started to get into ground resonance as he initially touched down. The flight instructor increased power to become briefly airborne and continued the maneuver to a normal practice hydraulic failure running landing. After the ground resonance experience, the flight instructor continued the flight training session for an additional 45 minutes and conducted another hydraulic failure running landing, several slope landings, and five hovering autorotations. Two of the hovering autorotations were described as rough, with an undesired drift to the front left. The flight instructor then left the airport where they had been practicing and returned to their home base airport where they conducted two straight-in autorotations and three 180-degree autorotations, all to a power recovery. After shut-down procedures were completed the two pilots were surprised when they discovered substantial damage, with buckling around the full circumference of the forward part of the tail boom and a crack in the skin at the 6 o’clock position. The flight instructor stated that he thought the damage occurred when they were conducting hovering autorotations. The two pilots reported that they were not injured.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The flight instructor’s inadvertent entry into ground resonance when demonstrating a hydraulic failure running landing, which resulted in substantial damage to the helicopter. Contributing to the accident was the pilot's and instructor pilot's failure to control the drift and rate of descent during the practice maneuvers.

Full narrative available

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