C172 PILOT REPORTS ENCOUNTERING HELICOPTER DOWNWASH DURING LANDING AND MOMENTARILY LOSING CONTROL.

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I TOOK OFF FROM ZZZ AT APPROX XA30. THIS WAS MY FIRST SOLO IN THE FLYING CLUB'S C172. THE SKY WAS CLR; THE WIND LESS THAN 5 KTS; THE VISIBILITY WAS EXCELLENT; THE TEMP WAS ABOUT 80 DEGS F. I DID 4 TOUCH-AND-GOES AT ZZZ. ALL OF THEM WERE UP TO MY STANDARDS. AFTER THAT; I HEADED TO ZZZ1. AS I ENTERED THE PATTERN; A HELI ANNOUNCED THAT HE HAD JUST LANDED IN THE GRASS NEXT TO RWY 22. I COULD SEE HIM THERE AS I WAS FLYING DOWNWIND. (IT APPEARED TO BE A JET RANGER.) I COMPLETED MY APCH AND DID A TOUCH-AND-GO ON RWY 22. AS I WAS TURNING L XWIND; I HEARD THE HELI ANNOUNCE THAT HE WAS TURNING L XWIND FOR RWY 22. HE WAS OBVIOUSLY BEHIND ME AS HE WAS STILL ON THE GRASS WHEN I WAS DOING MY TOUCH-AND-GO. I THOUGHT HE MUST BE DOING A LOW LEVEL PATTERN. AS I TURNED DOWNWIND HE ANNOUNCED HE WAS TURNING DOWNWIND. I COULD SEE HIM LOW AND NEAR THE RWY. I WAS AT 1000 FT MSL WHICH IS THE PATTERN ALT. AS I TURNED L BASE FOR RWY 22 HE MADE THE SAME ANNOUNCEMENT. HIS BASE TOOK HIM ALMOST ACROSS THE NUMBERS ON RWY 22 AND IT APPEARED HE WAS FLYING AT LESS THAN 100 FT OF ALT. HE ANNOUNCED HE WAS LNDG IN THE GRASS TO THE R SIDE OF RWY 22. I CALLED TO HIM AND LET HIM KNOW THAT I HAD HIM IN SIGHT AND THAT I WAS TURNING FINAL FOR RWY 22. AS I CONTINUED ON MY FINAL; I WAS THINKING OF MY RECENT TRAINING ABOUT WINGTIP VORTICES. I COULDN'T RECALL ANYTHING BEING TAUGHT ABOUT HELIS; ONLY LARGER PLANES AND JETS. MY INSTINCTS TOLD ME THOUGH THAT I SHOULD LAND BEYOND HIS TOUCHDOWN POINT IN CASE THERE MIGHT BE DOWNWASH FROM HIS ROTOR BLADES. I WAS XING THE NUMBERS AT APPROX 100 FT ALT AND WITHIN APPROX 200 FT OF HIM WHEN A VIOLENT UPDRAFT TOOK MY PLANE AND THREW ME TO THE R WITH MY L WING HIGH. I WOULD ESTIMATE A BANK ANGLE OF AT LEAST 60 DEGS. IN SPITE OF THE IMMEDIATE THOUGHT THAT I MIGHT CRASH ON MY FIRST FLT OF THE ACFT; I PUT IN FULL PWR; PULLED CARB HEAT; LOWERED THE NOSE; BROUGHT THE ACFT BACK TO WINGS LEVEL; AND FLEW R OF THE HELI SO IF I CONTINUED MY DSCNT I WOULD NOT CONTACT HIM. AHEAD WERE SEVERAL PARKED ACFT INCLUDING AT LEAST 1 PVT JET. IF I HAD TO LAND; THERE WAS A GOOD CHANCE I WOULD CONTACT ONE OF THOSE ACFT. I RETRACTED ABOUT 10 DEGS OF FLAPS AND THANKFULLY STARTED TO PICK UP SPD AND ALT. I ANNOUNCED A MISSED APCH AND LEFT THE PATTERN WITH NO DAMAGE; BUT A NEW APPRECIATION FOR THE DISTURBANCE CAUSED BY THE HELI. I THINK SOMEWHERE IN PVT PLT TRAINING THE DANGERS OF VORTICES CAUSED BY HELIS SHOULD BE EMPHASIZED. EVEN TRYING TO LAND A BIT AFTER HIS TOUCHDOWN POINT WASN'T GOOD ENOUGH IN THIS CASE. IN RETROSPECT; I PROBABLY SHOULD HAVE DONE A GAR. IF MY EXPERIENCE CAN HELP OTHER PLTS; I GUESS IT WAS WORTH IT. I KNOW I WAS ONLY 2 OR 3 SECONDS FROM CRASHING AND MY GOOD TRAINING KICKED IN JUST IN TIME TO SAVE ME FROM DISASTER.