VFR Over-The-Top
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VFR Over-the-Top (OTT) simply means flying over top of clouds for brief amount of time to avoid weather or turbulence. There are specific guidelines as to to when you may go OTT. Usually, you must ask ATC for permission to do so, or in absence of a controller, advise the nearest FSS or Center. You must always stay within VFR minimas when climbing and descending over the clouds.
The rules for flying VFR OTT vary greatly from country to country. Some rules, such as those contained in the US Federal Aviation Regulations, are quite simple to understand and easy to comply with. Others, such as the Canadian VFR OTT regulations contained in the Canadian Aviation Regulations, are much more complex and more difficult to comply with.