Definition
The maximum elevation figure is a number printed inside each quadrangle (bounded by ticked lines of latitude and longitude) on a VFR sectional chart that represents the highest known elevation within that quadrangle, including terrain and obstructions, rounded up with a buffer for safety. The figure is shown in thousands and hundreds of feet above mean sea level.
Plain English
On a sectional chart, each box has a number that tells you the highest thing in that box, ground or man-made, expressed in feet above sea level. If you stay above that number, you will clear everything inside that box.
Context Anchor
Pilots see MEFs on sectional charts when checking terrain and obstacle height during route planning, especially as part of the Environment portion of aeronautical decision-making.
Derivation
Maximum means the highest. Elevation refers to height above mean sea level. Figure here means a printed number on the chart. Together: the highest height-above-sea-level number for that section of the chart.
Why Pilots Care
MEFs give pilots a single reliable number to plan minimum safe altitudes and avoid terrain or obstacles in VFR conditions.
Analogy
Think of an MEF as the chart square’s “tallest thing here” label. It does not fly the airplane for you, but it warns you what height you must take seriously in that area.
Intuition Check
Do not read an MEF as a recommended or guaranteed safe cruising altitude. It is a charted height for the tallest known terrain or obstacle in that grid area, so the pilot still must choose an altitude that provides proper clearance.
Example Sentence 1
The MEF in the quadrangle ahead reads 4,500, so cruising at 6,500 gives plenty of margin over the ridge.
Example Sentence 2
With an MEF of 3,800 feet in the quadrangle, the flight was planned at 5,500 feet to maintain adequate clearance.