Hi s-d. .Sorry it took so long to get back here. I was looking in the Navcanada ATSAMM (management manual) and found the section dealing with parallel approaches. It says that there must be at least 4200' between centre lines (where they got this number I don't know) for "simultaneous INDEPENDENT parallel approaches", anything less than that then they are "Dependent approaches", ie. must be staggered. I don't know for sure if this is also in the CARs (air regs) or not, but they are our rules. So in YYZ on the north/south parallel runways the aicraft must be staggered. What impact this has on the controllers working arrival I'm not sure as I'm in a high level sector, however, it does start backing thing up for us. Hope this answers your question. Feel free to email me if you want me to find anything else..........Cheers