It most certainly started on avsim, available as a sticky on their FSX Tweak forum if anyone is after it.
They didn't all work for me, an hour or two just playing was far more efficient.
All the best,
Gerry Winskill wrote:
I can't remember where I found it but the following is a good writeup. It definitely wasn't Avsim and might be somewhere on PilotClub.