Aircraft Operations. Volume II - Construction of Visual and Instrument ...

Chapter 1
LLZ only
1.1 GENERAL
The localizer only procedure is a non-precision approach procedure. The general criteria apply with the following
exceptions.
1.2 INTERMEDIATE APPROACH
The intermediate approach segment shall terminate at the FAF (outer marker or any fix meeting the FAF requirements).
The width of the primary and secondary areas shall meet the criteria specified in Section 1, Chapter 1, 1.3.3,
“Intermediate approach segment area width”, the FAP being replaced by the FAF.
1.3 FINAL APPROACH SEGMENT
1.3.1 Beginning and end
The final approach segment shall start at the FAF. It shall terminate at the MAPt, which shall not be beyond the
threshold.
1.3.2 Alignment
In general, the localizer antenna is sited on the runway centre line; nevertheless, in some cases this is not possible. In
this case, the alignment of the final approach track with the runway centre line determines whether a straight-in or
circling approach may be established. (See general criteria of Part I, Section 4, Chapter 5, 5.2, “Alignment”.)
1.3.3 Areas
1.3.3.1 The final approach/initial missed approach area is defined by the outer edges of the OAS X surfaces
appropriate to the ILS Category I procedure between the FAF and the distance where those edges reach a height 300 m
(984 ft) above threshold level. After that point, the area shall be equal in width to the 300 m (984 ft) Y surface contour
(see Figure II-2-1-1).
1.3.3.2 Where there is no glide path a 3° glide path angle shall be used when determining the 300 m (984 ft) OAS
contour.
1.3.3.3 The X and Y surfaces mentioned above may be replaced by the approach and extended transitional
surfaces defined in items a) and c) of Section 1, Chapter 1, 1.4.7.2, “Definition of basic ILS surfaces”.
II-2-1-1 23/11/06