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| Item F/G content (see the rules provided later in this document) | Lower/Upper limit value |
|---|---|
| "SFC" (only in item F) | “000” (as Lower limit) |
| "UNL" (only in item G) | “999” (as Upper limit) |
| "XXXXXFT AGL" | add to the indicated value the elevation in FT of the local lowest point (for item G: the highest point) of the terrain to obtain the corresponding AMSL value; then apply the rules for Feet AMSL |
| "XXXXXFT AMSL" | calculate the corresponding FL value (based on standard atmosphere). The values entered for the lower limit shall be rounded down to the nearest 100 ft increment. For the upper limit, the value shall be rounded up. Rounding examples can be found in OPADD |
| "XXXXXFT ABOVE Above the WGS-84 ELLIPSOIDellipsoid" * | from the indicated value, subtract the local geoidUndulation (in FT) to obtain the corresponding AMSL value; then apply the ruled for Feet AMSL |
| "XXXXXM AGL" | add to the indicated value the elevation in M of the local lowest point (for item G: the highest point) of the terrain to obtain the corresponding AMSL value; then apply the ruled for Metres AMSL |
| "XXXXXM AMSL" | calculate the corresponding FL value (based on standard atmosphere). The values entered for the lower limit shall be rounded down to the nearest 100 ft increment. For the upper limit, the value shall be rounded up. Rounding examples can be found in OPADD |
| "XXXXXM ABOVE Above the WGS-84 ELLIPSOIDellipsoid" * | from the indicated value, subtract the local geoidUndulation (in M) to obtain the corresponding AMSL value; then apply the ruled for Metres AMSL |
| "FLXXX" | inserted the “XXX” value without the FL prefix and eventually left padded with ‘0’ in order to have 3 digits |
| "SMXXX" | calculate corresponding value in FL and insert this value (rounded down for lower limit, rounded up for upper limit) |
* ) The value "XXXXXFT ABOVE Above WGS-84 ELLIPSOIDellipsoid" is not used in the current NOTAM practice. It has been included in this table for completeness sake.
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