FAA Ground School Practice Test

If terrain elevation is 1295 ft MSL, what is the height above ground level (AGL) of the base of the ceiling?

1. 505 ft AGL

2. 400 ft AGL

3. 600 ft AGL

4. 300 ft AGL

The correct answer is: 505 ft AGL

To determine the height above ground level (AGL) of the base of the ceiling when given the terrain elevation of 1295 feet MSL (Mean Sea Level), you need to take into account the standard height of the ceiling. Typically, in aviation weather reports, ceilings are reported in terms of their vertical distance above ground level. When analyzing the options presented, an understanding of how MSL and AGL relate is essential. If the ceiling is measured to be 1800 feet MSL, for instance, the calculation to convert this to AGL involves subtracting the terrain elevation. Here's an example: - If the ceiling is at 1800 ft MSL and the terrain is at 1295 ft MSL: 1800 ft MSL - 1295 ft MSL = 505 ft AGL. This demonstrates that the base of the ceiling in this hypothetical case would be at 505 feet AGL. Choosing 505 ft AGL in the given question aligns with the understanding that the base of the ceiling must be derived from subtracting the terrain elevation from the total MSL height. Thus, this figure is correct because it correctly displays how to calculate vertical clearance from the ground to the cloud base