No need for the math model...
Canada uses TERPS, hold patterns are a pre-defined racetrack...
Yes, holds are a pre-defined racetrack, however, the obstacle clearance is a mathematical model.
reynoldsno1... The mathematical formulas has a "potential" for an infinite number of obstacle clearance dimensions.
However, based on the mathematical formulas, they have narrowed it down to a number of possible obstacle clearance models. The formulas are based on speed, temp, etc. and so the obstacle clearance models are also based on that.
ater... thanks for the reference! It seems that everyone has their own set of rules. Canada being based off of TERPS and, if I'm not mistaken, TERPS is based off of PANS-OPS. In any case, they're all pretty similar.