roncachamp
Final Approach
There is no priority given IFR traffic versus VFR traffic in terms of sequencing, but the guidance to controllers does tell them it's "first come, first served" among IFR traffic.
Actually, the guidance to controllers tells them to provide ATC service to aircraft on a "first come, first served" basis among all traffic as circumstances permit with a few exceptions; emergencies, Lifeguard, presidential travel, etc.
IOW, if a 172 is going to reach the IAF first, the controller doesn't break off the 172 to hold and allow a 757 behind the 172 to fly the approach first.
Actually, he might very well do just that. Slow behind fast just seems to work better than fast behind slow.