A triangle flight pattern is a flight pattern in which you fly from a base A to airport B, then to airport C and finally back to base A.
It is a complex flight pattern because you fly not only from the base and back, but also to airport C in between. The special thing about this flight pattern is that it is not symmetrical. This means that each route (A, B), (B, C) and (C, A) is only covered once. Since you want to cover each route equally often in each direction on scheduled flights, you need additional flight patterns that cover the opposite directions (B, A), (C, B) and (C, A). The easiest way to achieve this is to fly the pattern in the opposite direction.
