| Significance | Code | Meaning |
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| FIR | EGTT | London FIR | | | / | | | Qualifiers | Q | | | | PO | Obstacle clearance altitude | | | CH | changed | | | / | | | Traffic | I | IFR traffic affected | | | / | | | Purpose | N | For immediate attention of aircraft operators | | | B | For inclusion in Preflight Infomation Bulletins | | | O | Operationally significant for IFR flights | | | / | | | Scope | A | Aerodrome information | | | / | | | From flight level | 000 | Surface | | | / | | | Up to flight level | 999 | Unlimited | | | / | | | Centre Latitude | 5129N | 51° 29' North' | | Centre Longitude | 00028W | 0° 28' West | | Radius of area affected | 005 | 5 nautical miles |
| | INSTRUMENT APPROACH CHART-ILS / DISTANCE MEASURING EQUIPMENT I-RR RUNWAY 27R-PROCEDURE OBSTACLE CLEARANCE ALTITUDE ( H ) FOR CATEGORY II ILS TO INCREASE AS FOLLOWS : CATEGORY D INCREASE FROM 171 ( 93 ) TO 172 ( 94 ) UK AERONAUTICAL INFORMATION PUBLICATION AERODROME 2.EGLL-8-10 REFERS. |
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