Narrative:

I was conducting the initial night vision goggle (nvg) training for a company pilot. Flight maneuvers focused on normal takeoffs and landings; hover work and hover taxi with emphasis placed on the benefits and limitations associated with nvgs. He stated his biggest challenge was gauging his skid height above the ground in a hover. I allowed him several takeoffs and landings to and from a hover to get accustomed. He shared with me that he wore corrective lenses for nearsightedness; information that I failed to place enough importance to as I think it contributed to our hard landing. After two hours of training I had the training pilot place the helicopter in a stable 3' hover and; as per our brief; I announced and initiated a simulated engine failure by retarding the fuel flow control lever (throttle) toward the idle/cutoff position. Contrary to procedures the training pilot immediately increased collective pitch resulting in a climb and decayed rotor rpm. I countered by pushing down on the collective and telling him to lower the collective in an effort to save rpm. As we settled I commanded; 'pull collective' and pulled to cushion our landing. However; he continued to push down on the collective. We impacted in a level attitude with force sufficient to activate the ELT. Neither pilot sustained injury. I directed the training pilot to shut down the helicopter. We then exited the aircraft to inspect for damage. I found obvious deformities to the tail boom in three locations. Extent of the damage is yet to be determined. Factors that contributed to this incident: the training pilot's corrective lenses are fairly small and wire framed. Given that he is nearsighted; it is probable that he does not have optimum vision to either side of and below the nvg tubes. Even with my confirmation that we were at the correct skid height to initiate a hovering auto rotation; his response was to immediately increase collective pitch. I have no explanation as to why he countered me on the controls. He later stated that he did not want to raise the collective because the low RPM warning horn had been on too long. Insufficient time to affect a positive transfer of controls complicated the situation. While we would still have landed firmly; additional collective input could possibly have cushioned the landing enough to avoid damage to the helicopter. The maneuver is brief and even under ideal conditions a positive transfer would have to be very flawlessly executed let alone when the maneuver is improperly initiated. Disagreement in control input is probably the greatest contributing factor to this incident. Greater emphasis on the effects of corrective lenses to the wearer. I will be sure I know and appreciate the significance of their impact. Add discussion to the preflight brief and the maneuver description addressing the potential for transfer of controls if things go awry.

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Original NASA ASRS Text

Title: Helicopter pilots engaged in night vision goggle training suffer a hard landing out of an engine failure at hover maneuver.

Narrative: I was conducting the initial night vision goggle (NVG) training for a company pilot. Flight maneuvers focused on normal takeoffs and landings; hover work and hover taxi with emphasis placed on the benefits and limitations associated with NVGs. He stated his biggest challenge was gauging his skid height above the ground in a hover. I allowed him several takeoffs and landings to and from a hover to get accustomed. He shared with me that he wore corrective lenses for nearsightedness; information that I failed to place enough importance to as I think it contributed to our hard landing. After two hours of training I had the training pilot place the helicopter in a stable 3' hover and; as per our brief; I announced and initiated a simulated engine failure by retarding the fuel flow control lever (throttle) toward the idle/cutoff position. Contrary to procedures the training pilot immediately increased collective pitch resulting in a climb and decayed rotor rpm. I countered by pushing down on the collective and telling him to lower the collective in an effort to save rpm. As we settled I commanded; 'pull collective' and pulled to cushion our landing. However; he continued to push down on the collective. We impacted in a level attitude with force sufficient to activate the ELT. Neither pilot sustained injury. I directed the training pilot to shut down the helicopter. We then exited the aircraft to inspect for damage. I found obvious deformities to the tail boom in three locations. Extent of the damage is yet to be determined. Factors that contributed to this incident: The training pilot's corrective lenses are fairly small and wire framed. Given that he is nearsighted; it is probable that he does not have optimum vision to either side of and below the NVG tubes. Even with my confirmation that we were at the correct skid height to initiate a hovering auto rotation; his response was to immediately increase collective pitch. I have no explanation as to why he countered me on the controls. He later stated that he did not want to raise the collective because the low RPM warning horn had been on too long. Insufficient time to affect a positive transfer of controls complicated the situation. While we would still have landed firmly; additional collective input could possibly have cushioned the landing enough to avoid damage to the helicopter. The maneuver is brief and even under ideal conditions a positive transfer would have to be very flawlessly executed let alone when the maneuver is improperly initiated. Disagreement in control input is probably the greatest contributing factor to this incident. Greater emphasis on the effects of corrective lenses to the wearer. I will be sure I know and appreciate the significance of their impact. Add discussion to the preflight brief and the maneuver description addressing the potential for transfer of controls if things go awry.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.