it cant have just ripped off in mid flight. you must have done a lot of structural damage before and not noticed it, or it didnt rip off at all it just fell off because you didnt put locktite on your landing gear bolts. always use locktite! so many people ignore this small thing but it makes a huge difference. metal to metal, always locktite no matter what. there are different colors for different strengths and applications

blue- anti vibration
red- anti vibration, heat resistant, semi-permanent
green- good luck getting it off....green is used for holding cylinder walls or something in place in car engines. there doesnt even have to be a thread for this to attach and it will not melt until such a ridiculously high temperature. four stroke mufflers dont even come close to melting this. i use it a lot with a whole lot of force after running your engine it will usually loosen but i would not recomnend using it if you might want to reposition your muffler.

i dont know your skill level but if your not the best flyer use nylon bolts for your landing gear. if you have a rough landing they will be the weakest point and will simply snap. keep a few extra bolts and this will help you, one guy at the field uses these on everything and never damages his landing gear block. worst he does is snaps the bolts....i think he broke a prop once to but replacing 2 bolts and a prop at the field beats packing it in for the day and going home to repair. personally i use stainless steel bolts and never had a problem, but i dont land hard.