Narrative:

The situation arose near the end of a solo flight. I had finished flying; and approached the airport; making frequent radio calls stating how far out I was and how I planned to enter the pattern (right hand traffic). I did a standard 45 degree turn into a right downwind. As I came abeam the numbers; a helicopter pilot that was not flying the pattern and had not made any radio calls up until this point said that he was aborting his landing; because traffic (me) had cut him off. The helicopter; who I had not seen until he made his call; was flying above pattern altitude and was flying a long final about 20 degrees off from being parallel to the runway (imagine flying in a straight line from a turn to left base to the end of the runway). Immediately after hearing his call about me cutting him off; I apologized and offered to fly a long downwind and let him finish his landing. He said it was fine and told me I was ok to go ahead and land. After hearing this; I flew a standard base; and noticed during final that the helicopter (a military helicopter); had flown to a lower altitude (about 200ft to my left and about 100 feet above me) and had lined up parallel with the field. As I continued to fly my final; I noticed how close the helicopter was; and I remember distinctly thinking that it would significantly disturb the air. Being an inexperienced pilot in an unfamiliar situation; I trusted that the helicopter pilot knew what he was doing and decided that the best thing I could do was fly a standard landing that I had performed numerous times before. At this point; I was about 60-70 feet AGL and was focusing on getting lined up and ready to flare. The helicopter was now directly over the runway; about 70 feet in front of me and was about 100-120 feet AGL. At about this time; I ended up getting caught in the helicopter's wake turbulence. I have studied wake turbulence coming off of jets and large aircraft in ground school; but had never learned about or considered wake turbulence coming from above me and coming from a source that was moving at the same speed I was traveling at. Because of my low airspeed (~70 mph) and the helicopter's huge amount of wake turbulence; it was near-impossible to control my aircraft. I was applying the correct inputs as well as I could; but the aircraft was being rotated and thrown in directions faster than the airplane was able to maneuver. Additionally; since I was travelling at the same speed as the helicopter when the turbulence started; the turbulence was not a single instance; but instead lasted for several seconds. I distinctly remember accepting that I was going to crash. Fortunately; I was able to control the aircraft well enough that the helicopter flew far enough ahead of for me to get out of the wake and regain full control of the airplane. I was able to perform a go around and successfully land on my next attempt. Meanwhile; the helicopter continued flying straight and came to a hover about half a mile from the runway.

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Original NASA ASRS Text

Title: C172 pilot reported having difficulty maintaining control of his aircraft on short final when he encountered wake turbulence from a military helicopter operating near the end of the runway.

Narrative: The situation arose near the end of a solo flight. I had finished flying; and approached the airport; making frequent radio calls stating how far out I was and how I planned to enter the pattern (right hand traffic). I did a standard 45 degree turn into a right downwind. As I came abeam the numbers; a helicopter pilot that was not flying the pattern and had not made any radio calls up until this point said that he was aborting his landing; because traffic (me) had cut him off. The helicopter; who I had not seen until he made his call; was flying above pattern altitude and was flying a long final about 20 degrees off from being parallel to the runway (imagine flying in a straight line from a turn to left base to the end of the runway). Immediately after hearing his call about me cutting him off; I apologized and offered to fly a long downwind and let him finish his landing. He said it was fine and told me I was ok to go ahead and land. After hearing this; I flew a standard base; and noticed during final that the helicopter (a military helicopter); had flown to a lower altitude (about 200ft to my left and about 100 feet above me) and had lined up parallel with the field. As I continued to fly my final; I noticed how close the helicopter was; and I remember distinctly thinking that it would significantly disturb the air. Being an inexperienced pilot in an unfamiliar situation; I trusted that the helicopter pilot knew what he was doing and decided that the best thing I could do was fly a standard landing that I had performed numerous times before. At this point; I was about 60-70 feet AGL and was focusing on getting lined up and ready to flare. The helicopter was now directly over the runway; about 70 feet in front of me and was about 100-120 feet AGL. At about this time; I ended up getting caught in the helicopter's wake turbulence. I have studied wake turbulence coming off of jets and large aircraft in ground school; but had never learned about or considered wake turbulence coming from above me and coming from a source that was moving at the same speed I was traveling at. Because of my low airspeed (~70 mph) and the helicopter's huge amount of wake turbulence; it was near-impossible to control my aircraft. I was applying the correct inputs as well as I could; but the aircraft was being rotated and thrown in directions faster than the airplane was able to maneuver. Additionally; since I was travelling at the same speed as the helicopter when the turbulence started; the turbulence was not a single instance; but instead lasted for several seconds. I distinctly remember accepting that I was going to crash. Fortunately; I was able to control the aircraft well enough that the helicopter flew far enough ahead of for me to get out of the wake and regain full control of the airplane. I was able to perform a go around and successfully land on my next attempt. Meanwhile; the helicopter continued flying straight and came to a hover about half a mile from the runway.

Data retrieved from NASA's ASRS site 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.