Narrative:

After about 1.5 hours of practice; returned to the airport for 'touch and goes'. Traffic at the airport was light; and the winds were reported as 290 at 5 KTS. On the first touch and go (runway 31R); tower cleared a caravan to take off in front of me. This is common at this airport; so I did not think anything of it as I have taken off and landed behind caravans on many occasions. After the touch and go; I began to climb. At about 400 ft; my aircraft entered an uncommanded approximately 45 degree bank to the right. I recovered using all flight controls; particularly full left rudder; full left aileron and lowered nose to reduce angle of attack. Upon recovery I called tower to ask if any jets/heavies had taken off recently. They said none had and I reported the event to them at that time. I decided to terminate my flight at that point and asked to make the next landing a full stop. I am not sure; but I think the situation may have been just right to cause the relatively small amount of wake turbulence created by the caravan to cross my flight path. The training material I have used all puts the focus on much larger airplanes coming to conflict with much smaller airplanes when discussing wake turbulence (e.g. Passenger jets); however I think it would be beneficial to have the training examples depict planes with a smaller disparity in size to show that it does not take that much difference in size to cause a wake turbulence encounter.

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Original NASA ASRS Text

Title: A C172 PLT REPORTED ENCOUNTERING WAKE TURB FROM A PRECEDING CARAVAN ON DEP THAT REQUIRED FULL CONTROL INPUT FOR RECOVERY.

Narrative: AFTER ABOUT 1.5 HOURS OF PRACTICE; RETURNED TO THE ARPT FOR 'TOUCH AND GOES'. TFC AT THE ARPT WAS LIGHT; AND THE WINDS WERE RPTED AS 290 AT 5 KTS. ON THE FIRST TOUCH AND GO (RWY 31R); TOWER CLEARED A CARAVAN TO TAKE OFF IN FRONT OF ME. THIS IS COMMON AT THIS ARPT; SO I DID NOT THINK ANYTHING OF IT AS I HAVE TAKEN OFF AND LANDED BEHIND CARAVANS ON MANY OCCASIONS. AFTER THE TOUCH AND GO; I BEGAN TO CLB. AT ABOUT 400 FT; MY ACFT ENTERED AN UNCOMMANDED APPROX 45 DEG BANK TO THE R. I RECOVERED USING ALL FLT CTLS; PARTICULARLY FULL L RUDDER; FULL L AILERON AND LOWERED NOSE TO REDUCE ANGLE OF ATTACK. UPON RECOVERY I CALLED TOWER TO ASK IF ANY JETS/HEAVIES HAD TAKEN OFF RECENTLY. THEY SAID NONE HAD AND I RPTED THE EVENT TO THEM AT THAT TIME. I DECIDED TO TERMINATE MY FLT AT THAT POINT AND ASKED TO MAKE THE NEXT LNDG A FULL STOP. I AM NOT SURE; BUT I THINK THE SITUATION MAY HAVE BEEN JUST RIGHT TO CAUSE THE RELATIVELY SMALL AMOUNT OF WAKE TURBULENCE CREATED BY THE CARAVAN TO CROSS MY FLIGHT PATH. THE TRAINING MATERIAL I HAVE USED ALL PUTS THE FOCUS ON MUCH LARGER AIRPLANES COMING TO CONFLICT WITH MUCH SMALLER AIRPLANES WHEN DISCUSSING WAKE TURBULENCE (E.G. PAX JETS); HOWEVER I THINK IT WOULD BE BENEFICIAL TO HAVE THE TRAINING EXAMPLES DEPICT PLANES WITH A SMALLER DISPARITY IN SIZE TO SHOW THAT IT DOES NOT TAKE THAT MUCH DIFFERENCE IN SIZE TO CAUSE A WAKE TURBULENCE ENCOUNTER.

Data retrieved from NASA's ASRS site as of May 2009 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.