FAA Flight Instructor Airplane (FIA)Navigation and AirspaceHard
A CFI is teaching sectional chart interpretation and points to the number '57' printed in large digits within a quadrangle of latitude/longitude lines. The CFI explains this is the Maximum Elevation Figure (MEF), representing:
- Athe elevation of the highest charted airport within that quadrangle
- Bthe highest known feature within the quadrangle, plus a safety buffer, rounded up to the next 100 feet, expressed as 5,700 feet MSL
- Cthe minimum safe altitude a pilot must maintain over any terrain in that quadrangle
- Dthe average terrain elevation within that quadrangle, rounded to the nearest 100 feet
Show answer & explanationAnswer & explanation
Correct answer: B. the highest known feature within the quadrangle, plus a safety buffer, rounded up to the next 100 feet, expressed as 5,700 feet MSL
An MEF represents the elevation of the highest known feature (terrain, obstacle, or vegetation) within a quadrangle, plus a vertical safety buffer, rounded up to the next 100-foot increment. '57' printed on the chart means 5,700 feet MSL, ensuring at least the standard buffer above the highest known obstruction.
Why the other options are wrong
- A. MEF is based on terrain/obstacles, not specifically airport elevation.
- C. MEF is informational, not a regulatory minimum altitude requirement.
- D. MEF reflects the highest feature, not an average elevation.
Maximum Elevation Figure (MEF)
The elevation figure printed in each quadrangle of a sectional chart, representing the highest known feature plus a safety buffer, rounded up to the next 100-foot increment.
- Printed as two large and two small digits (e.g., '5⁷' = 5,700 ft).
- Buffer accounts for man-made obstacles and vegetation.
- Not a legal minimum altitude, but a planning safety reference.
Memory trick: 'MEF: highest feature plus buffer, rounded up like rounding up a bill.'