What does MEF mean in Aircraft & Aviation?

Maximum elevation figure

Maximum elevation figure or MEF is the a type of VFR altitude which indicates the height of the highest feature within a quadrangle area. It is of interest to pilots, who want to be aware of the highest mountain peaks and tall towers nearby, so that they can fly above them to avoid controlled flight into terrain. In a VFR context, this altitude is commonly referred to as a "quadrantal altitude" Unlike the Minimum safe altitude used for IFR flight, the MEF does not include any margin for aircraft clearance above the terrain nor for altimeter error. In the US, the Federal Aviation Administration issues sectional charts. Each rectangular area covering one degree of latitude and one degree of longitude is divided into four smaller areas called quadrangles, each spanning half a degree of latitude and half a degree of longitude. Each quadrangle has its MEF printed in it in thousands and hundreds of feet above mean sea level. For example, 105, means that the highest elevation is 10,500 feet within that quadrangle.

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