I think this is an ongoing issue with a lot of FR models. Our Legacy had the same thing happen but luckily didn't fly off, just came loose and dropped to the side of the windshield. The shop folks "fixed" it by tightening the acorn nut on the spindle at the base of the arm - it tends to come loose, mainly because the FR folks didn't put it together using the serrated washer indicated and provided by the wiper system manufacturer. Instead, they used a standard flat washer. After tightening the driver side and ignoring the passenger side (typical service idiots!), my passenger side came loose, flopped over under the driver side and bent the fool out of the wiper arm. I managed to find new blades that fit (they were all bent up, too) at Camping World (Trico makes a very heavy duty wiper unit, much heavier and nicer than the OEM), but the only source I can find for the new arm is to order it directly from FR at a cost of about $40 (not bad from what I've seen elsewhere for other arms). I removed the arm myself, pounded it out straight and used vice grips and Crescent wrenches to twist it back into shape and I think I can live with it as it is now. Be sure to tighten the acorn nuts on both sides! I'm beginning to think FR should issue a safety recall on this since wipers are involved. FR: Are you listening???
2015 Legacy SR340 360RB
2014 Jeep Wrangler Unlimited Toad
Gigi, Poppy and Sadie Lady...On the road, but not full time!