Airport chart walkthroughs / GCN

Grand Canyon National Park (GCN) on the sectional chart

FAA Las Vegas sectional, Sep 3, 2026 edition. Study use only, not for navigation.

How to read the Class D airspace, part-time tower and CTAF at Grand Canyon National Park on the FAA Las Vegas sectional: the kind of chart reading the Part 107 test asks for. Two practice questions with worked answers below.

What the chart and FAA data show

How to read it

Find the dashed blue circle around GCN: that is Class D airspace. The boxed number inside it, [91], is the ceiling in hundreds of feet MSL, so this Class D goes up to 9,100 ft MSL. Subtract the field elevation (6,608.9 ft) to get the height above the airport: about 2,491 ft. Chart altitudes for airspace are MSL unless marked AGL.

In the airport data block, the star after the tower frequency (CT - 119.0) means the tower is part-time, and the magenta C means that frequency is also the CTAF when the tower is closed. When the tower closes, the airspace usually reverts to Class E or Class G; the Chart Supplement has the details.

For a drone: flying a small UA in Class D airspace needs ATC authorization first (LAANC or FAA DroneZone; 14 CFR 107.41).

Practice: 2 questions on this chart

Practice question 1 of 2

Refer to the marked airport. What are the vertical limits of the Class D airspace at GRAND CANYON NTL PARK (GCN)?

1. A. From the surface up to and including 9,100 ft AGL
2. B. From the surface up to and including 2,491 ft MSL
3. C. From the surface up to and including 9,100 ft MSL

Show the answer

Answer: C. From the surface up to and including 9,100 ft MSL

Inside the dashed blue Class D circle you'll find a number in a box: [91]. It gives the ceiling in hundreds of feet MSL, so this Class D goes from the surface to 9,100 ft MSL. Field elevation is 6,609 ft MSL, so the Class D extends about 2,491 ft above the airport. Chart altitudes for airspace are MSL unless marked AGL.

Question ID: c-d60b1f1507 | ACS UA.II.A.K1c

Practice question 2 of 2

Refer to the marked airport. If the control tower at GRAND CANYON NTL PARK (GCN) is not in operation, which frequency should be used as the CTAF to monitor airport traffic?

1. A. 122.95
2. B. 119.0
3. C. 124.3

Show the answer

Answer: B. 119.0

The airport data block shows the tower frequency after CT: CT - 119.0, followed by a star and a magenta C. The star means the tower is part-time (hours are listed in the Chart Supplement: JUN 1 - SEP 30 - 0600-2000, OCT 1 - MAY 31 0700-1900 local). The magenta C next to it means the tower frequency becomes the CTAF when the tower is closed, so the answer is 119.0. The other choices are frequencies printed nearby for other services (ATIS, ground, UNICOM). When the tower closes, Class D airspace usually reverts to Class E or Class G; check the Chart Supplement.

Question ID: c-1c1a03812a | ACS UA.V.A.K1, UA.V.A.K2, UA.V.B.K2

Related guides: How to read a sectional chart, CTAF and part-time towers, Airspace classes for drone pilots.