Lesson E1 1:20 20 of 26
How to read obstacle symbols: the MSL elevation on top, the AGL height below.
The video plays from YouTube. FAA San Francisco Sectional, effective 29 OCT 2026. Not for navigation.
Man-made obstacles are printed in blue. Sectionals typically show those more than 200 feet above the ground. In yellow city areas, the cutoff is more than 299 feet. Each obstacle shows two numbers. Look at this tower on high ground south of Salinas.
The top number, 3,615, is the elevation of its top in feet MSL. That is the number to compare with your altimeter. The number in parentheses, 226, is its height above the ground in feet AGL. Obstacles 1,000 feet AGL and higher use a taller symbol. This tower near Loma Prieta tops out at 4,052 feet MSL and stands 1,554 feet tall.
Where several obstacles stand close together, the chart may show one group symbol. The Moss Landing stacks are one example. The towers east of Salinas Municipal are another. UC means the obstacle is under construction or reported. Its position and elevation are not verified. These two near Panoche show only their MSL elevation. Obstacles may be lit or unlit. Guy wires may extend outward from these structures, so give them room.
Before you fly, check the current chart, the Chart Supplement and NOTAMs.
A discovery flight is actual flight training with a certified flight instructor at the Salinas Airport. Your hands on the controls, with the chart on your knee.
