Narrative:

This flight was a training flight with one of our new hires. There were no issues with this student and their flying skills. We were going to be covering basic maneuvers and some emergency procedures. After briefing the student with the lesson plan and illustrating what to expect on the flight; we proceeded out to the ramp for the flight. The flight was conducted under VFR flight rules; and lasted a total of 1.4 hours. We departed for an outlying to conduct the flight due to the amount of traffic at our home airport. We joined the outlying field traffic pattern and started off with basic maneuvers; normal approach; air taxi; quick stop; max P take-off; and steep approach. Then I started conducting some emergency procedures such as stuck power pedal; and hydraulic failure. These two procedures require a shallow approach running landing. I conducted two hydraulic failure procedures because I felt that his first approach for this procedure was not shallow enough. After the first running landing for the hydraulic failure and we were stopped on the runway; I turned the hydraulics back on. I then explained to the student to shallow out his approach to make the emergency landing easier. I then took controls; picked up to a hover and back taxied closer to the approach end of the runway. We then moved on to some slope landings in the grass on the west side of runway xx. After the slope landings; we moved on to some hover auto rotations over grass as well. This is where I think the damage may have happened. Before conducting the hover auto rotations; I had the student set down the aircraft so that I could confirm a level surface. We conducted 5 hover auto rotations over this spot from what looked to me a 3-5 foot hover height. The first one was descent; but the student was not working the pedals to maintain heading. The 2nd hover auto; we started to drift forward and to the left slightly and we did not land as smooth as I would have liked it. I then explained to try to maintain current position over the ground and just to let the aircraft settle before pulling collective pitch to cushion the landing. The 3rd hover auto; the student did the same thing; forward and slight drift to the left with a rougher landing than I would like; but initially controlled the heading much better when I reduced the throttle; well within commercial pts standards. At no point in time after these hover auto rotations that I had the idea of a hard landing go through my mind. Everything felt normal to me in the cockpit. The 4th and 5th hover auto; I pretty much demonstrated the maneuver myself with a very smooth and gentle set down. At this point of the flight; the student and I were quite hot in the cockpit and proceeded to rejoin the traffic pattern. We finished off the training flight with two straight in auto rotations power recovery and three 180 degree auto rotations power recovery. Flight characteristics of the aircraft seemed to be normal. We then returned to our home base to end the flight training lesson. We then parked the aircraft in front of the home base hangar and proceeded for normal shut down the aircraft. After shut down; and once the blades had stopped turning; I got out of the aircraft and proceeded into operations to tell the radio room what my landing time was because I could not talked to them on the proper frequency. I then headed back outside to get with my student and he had several questions about the flight log. After helping the student; we grabbed our things from the aircraft and proceeded inside for a de-briefing. This is where I know I made a big mistake. I did not do a post flight; I would have seen the damage and taken the proper action; but this is not the case. Unfortunately; I found out about the damage from my student when I was heading back out to the ramp to speak with my boss. I do not know who noticed the damage first; but as I was walking out to the ramp; I noticed several people around the aircraft. Once my student told me about the damage; I proceeded out the aircraft to observe the damage. I was in disbelief about the damage and began trying to think about when this could have occurred. Once again; I did not notice any abnormal flight characteristics of the aircraft throughout the entire flight.

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Original NASA ASRS Text

Title: An AS350 helicopter instructor reported a wrinkled tail boom discovered during post flight believed to have been the result of a hard landing during a student's auto rotation landing.

Narrative: This flight was a training flight with one of our new hires. There were no issues with this student and their flying skills. We were going to be covering basic maneuvers and some emergency procedures. After briefing the student with the lesson plan and illustrating what to expect on the flight; we proceeded out to the ramp for the flight. The flight was conducted under VFR flight rules; and lasted a total of 1.4 hours. We departed for an outlying to conduct the flight due to the amount of traffic at our home airport. We joined the outlying field traffic pattern and started off with basic maneuvers; normal approach; air taxi; quick stop; max P take-off; and steep approach. Then I started conducting some emergency procedures such as stuck power pedal; and hydraulic failure. These two procedures require a shallow approach running landing. I conducted two hydraulic failure procedures because I felt that his first approach for this procedure was not shallow enough. After the first running landing for the hydraulic failure and we were stopped on the runway; I turned the hydraulics back on. I then explained to the student to shallow out his approach to make the emergency landing easier. I then took controls; picked up to a hover and back taxied closer to the approach end of the runway. We then moved on to some slope landings in the grass on the west side of Runway XX. After the slope landings; we moved on to some hover auto rotations over grass as well. This is where I think the damage may have happened. Before conducting the hover auto rotations; I had the student set down the aircraft so that I could confirm a level surface. We conducted 5 hover auto rotations over this spot from what looked to me a 3-5 foot hover height. The first one was descent; but the student was not working the pedals to maintain heading. The 2nd hover auto; we started to drift forward and to the left slightly and we did not land as smooth as I would have liked it. I then explained to try to maintain current position over the ground and just to let the aircraft settle before pulling collective pitch to cushion the landing. The 3rd hover auto; the student did the same thing; forward and slight drift to the left with a rougher landing than I would like; but initially controlled the heading much better when I reduced the throttle; well within commercial PTS standards. At no point in time after these hover auto rotations that I had the idea of a hard landing go through my mind. Everything felt normal to me in the cockpit. The 4th and 5th hover auto; I pretty much demonstrated the maneuver myself with a very smooth and gentle set down. At this point of the flight; the student and I were quite hot in the cockpit and proceeded to rejoin the traffic pattern. We finished off the training flight with two straight in auto rotations power recovery and three 180 degree auto rotations power recovery. Flight characteristics of the aircraft seemed to be normal. We then returned to our home base to end the flight training lesson. We then parked the aircraft in front of the home base hangar and proceeded for normal shut down the aircraft. After shut down; and once the blades had stopped turning; I got out of the aircraft and proceeded into operations to tell the radio room what my landing time was because I could not talked to them on the proper frequency. I then headed back outside to get with my student and he had several questions about the flight log. After helping the student; we grabbed our things from the aircraft and proceeded inside for a De-briefing. This is where I know I made a big mistake. I did not do a post flight; I would have seen the damage and taken the proper action; but this is not the case. Unfortunately; I found out about the damage from my student when I was heading back out to the ramp to speak with my boss. I do not know who noticed the damage first; but as I was walking out to the ramp; I noticed several people around the aircraft. Once my student told me about the damage; I proceeded out the aircraft to observe the damage. I was in disbelief about the damage and began trying to think about when this could have occurred. Once again; I did not notice any abnormal flight characteristics of the aircraft throughout the entire flight.

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.