Grand Canyon Ntl Park (GCN) · Las Vegas Sectional, 12 Jun 2025 – 7 Aug 2025 · September_2026_Special_Edition.pdf, p. 10 · Not for navigation
If GRAND CANYON NTL PARK (GCN) control tower is not in operation, which frequency should be used as a Common Traffic Advisory Frequency (CTAF) to monitor airport traffic?
Why: This is one of the FAA's own two published sample questions for the October 2026 image-based test format, using this exact chart excerpt. The airport data block lists the tower frequency underlined to show it doubles as the CTAF when the tower is closed — 119.0 is that frequency for GCN.
124.3 is a different frequency shown in the data block (ATIS or ground, not the tower/CTAF frequency) and does not serve as the CTAF when the tower closes.
122.95 is a different frequency also printed in GCN's data block (not the tower frequency), so it is not the one that doubles as CTAF when the tower is closed.