AIM ¶ 4-1-5 — IFR Release at Non-Towered Airports

When you're flying IFR into an airport without an operating control tower, ATC will tell you to switch to the airport advisory frequency (CTAF) once direct communication with them is no longer needed. This matters because:

• ATC and centers don't have local traffic information — they don't know which runway is in use or what VFR traffic is operating in the pattern.
• The instrument approach you're flying may not align with the runway actually in use at that field.
• Other pilots in the pattern are self-announcing on CTAF, not talking to ATC.

As a pilot, you should switch to the airport advisory frequency expeditiously once authorized so you can:

• Hear position reports from VFR and IFR traffic in the pattern.
• Determine the runway in use and wind conditions.
• Self-announce your position on the approach.

This is recommended guidance, not a regulatory mandate, but it's a critical safety practice on every IFR arrival to a non-towered field. Get the airport advisory information early — ideally before you're established on the approach.