TAAMGuy
As someone who works a lot of departures in a shift, maybe 15-25% use the VNAP-A profile. Some don't use it for noise purposes, but as a means to get to noise termination altitude quicker hoping for an earlier turn on course. AC seem to use the A when departing in the opposite direction of destination and the B the rest of the time, with a few exceptions. This turn on course sometimes does not come any earlier due to preceding traffic on the same route which they need to be spaced with.
The tower is required to give traffic to departure 3 miles in trail and the extra time spacing required to achieve this when an A departure is followed by a B is in the order of 15 seconds. On a runway which has 40+ departures an hour and maybe 6-10 of them are A departures, the extra time spent waiting could be as much as 2.5 minutes per hour. In reality this doesn't happen: we use mixed mode some of the time, so the A departure profile is a non-issue; there are types which are turned and therefore another non-issue; and we seldom have constant demand.
There are times, however, when the integration of A departures at YYZ does cause delays to mount. I'm thinking of departures from 33R when 33L is the landing runway. In this scenario there is a headwind exceeding 25kts on the surface (otherwise we wouldn't be using this operation) and usually a stronger wind aloft. Because of the reduced airspeed on the A departure and the increased headwind, ground speed is so low that the time spacing needed to achieve 3 miles in trail is much increased: I would estimate that it could be closer to 20-25 seconds extra. Some of this extra time can be filled with traffic that is eligible for turning and/or runway crossings (which we have many of in this configuration) but delays are caused without a doubt.
I, and i suspect most of my colleagues, would much prefer that all aircraft fly the same (preferably B) profile all of the time. Heavy types can fly the A without much impact on operations as spacing behind them is increased anyway and their airspeed on climb, even using the A, is greater than say a lightly loaded A319.
Maybe rather than trying to find a "decision support tool" we should do more to explain to those who use the A for "selfish" reasons, that their decision actually costs more for traffic behind than it benefits the few aircraft that use it?
DC