| Significance | Code | Meaning |
|---|
| FIR | EGTT | London FIR | | | / | | | Qualifiers | Q | | | | OB | Obstacle | | | CE | erected | | | / | | | Traffic | I | IFR traffic affected | | | V | VFR traffic affected | | | / | | | Purpose | M | Miscellaneous | | | / | | | Scope | A | Aerodrome information | | | E | En-Route information | | | / | | | From flight level | 000 | Surface | | | / | | | Up to flight level | 004 | 400 feet QNE | | | / | | | Centre Latitude | 5139N | 51° 39' North' | | Centre Longitude | 00019W | 0° 19' West | | Radius of area affected | 001 | 1 nautical miles |
| | UNLIT FENCE LINE ERECTED WITHIN AREA BOUNDED BY WITHIN 10M RADIUS POSITION 513928.0N 0001937.0W-513923.9N 0001936.0W-513925.0N 0001920.6W ( NORTH SIDE GRASS OPPOSITE D TAXIWAY AND HELIPAD,ELSTREE AERODROME ) HEIGHT 6FT ABOVE GROUND LEVEL / 338FT ABOVE MEAN SEA LEVEL |
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