One of the most important numbers on a sectional is the Maximum Elevation Figure, or MEF. The MEF depicts the lowest altitude you can fly and still be assured to clear every obstacle within that quadrant. MEF's are calculated two ways, one for natural obstacles, and one for man-made obstacles.  Each method ensures the highest level of safety and that as long as you stay … [Read more...] about Maximum Elevation Figure (MEF) – Sectional Chart