Green on, Go!
That is the protection required for a Cat 1 ILS when the weather is near the minima. At an airfield that is capable of LWMO procedures from Cat 2 down to Cat3b, even more stringent procedures will be in force. First, special holding points are painted at appropriate places around the airport to ensure the protection and integrity of the ILS transmission. Secondly significant separation is provided in flight to ensure no aircraft on the ILS will be affected by an aircraft in front distorting the localiser and glide slope signal. These are the LWMO Airport Requirements straight from our ops manual we
“MUST” follow if we are to conduct a LWMO approach.
LWMO Airport Requirements
The Commander must be satisfied that Low Visibility Procedures are in force before commencing any LWMO approach. Clearance to fly a CAT 2 or CAT 3 approach is considered confirmation that LVP are in force.
Low Visibility Procedures − Before commencing LWMO, Airport Operators will implement Low Visibility Procedures (LVP). Pilots must be aware of the ILS sensitive/critical areas and LWMO holding points when taxying to the runway and when using LWMO runway exits after landing.
Serviceability of the airfield and ground equipment is the responsibility of the airfield operator. When LVP are in force, crews should assume the airfield operator has complied with all special procedures, lighting requirements and electrical requirements.
If RVR’s improve during the approach, ATC may cease LVP and revert to CAT 1 operations resulting in a loss of signal protection for CAT 2 and CAT 3 ILS procedures.
At some airports, particularly in Europe, ATC may announce either on VHF or via ATIS, that LWMO is operational to CAT 2 only. This allows ATC to reduce aircraft spacing to less than that required for CAT 3 operations. The airport surface area is still protected, however ILS signals may be affected by preceding traffic, due to the reduction in spacing. In such cases, due to normally high traffic density at such airports, it is unlikely that ATC will approve a crew request for a CAT 3 approach unless RVR values limit CAT 2 operations.