The reason people are not abiding by PTL's-
Hold on the ground for 1 hour to meeet PTL- cop 15 mins holding, land 1 hr 15 mins late.
Disregard PTL and depart anyway- cop 15 mins holding arrive 15 mins late.
Either way you get holding, but I am yet to be worse off by not following the PTL. Sometimes when we have abided by the PTL I have seen bigger bottlenecks out of the pilbra than if we had departed when we were ready.
Do you see why we disregard it? Its a load of *$#@$!
As for taxi slot times in 10 minute blocks- nice theory but what if everyone taxis in the last couple of minutes of the 10 mins slot and the next group are ready at the start of their 10 minute slot.
I am not blaming ATC but these band aid patches dont work. WAC and airservices need to fix the real problems!