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

Part II — Section 1, Chapter 5 II-1-5-3
5.5.2 Arrival and initial approach obstacle clearances
The arrival and initial approaches shall not be made below an altitude which provides a clearance of 300 m (1 000 ft)
above all obstacles within the area defined in Section 2, Chapter 6, 6.2.2, “Procedures based on predetermined tracks”.
However, this altitude should not be lower than the altitude at which the glide path will be intercepted, and if a
procedure turn is required not lower than the procedure turn altitude.
5.6 INTERMEDIATE AND FINAL APPROACH AREA AND OBSTACLE CLEARANCES
5.6.1 Combined intermediate and final approach area
5.6.1.1 This is an area symmetrical about the extended centre line extending from a point situated at a distance of
D calculated as in 5.6.2.1 b) from the threshold to the point at which the final approach is commenced. The
intermediate approach shall normally be commenced at a distance not exceeding 28 km (15 NM) from the threshold.
The intermediate approach transforms into the final approach at the point where the aircraft intercepts the descent path.
5.6.1.2 The area has a constant width of 600 m from its origin at the distance D from the threshold as in 5.6.2.1
b), to a point 1 060 m before the threshold. From this point the area widens with a splay of 15 per cent on either side to
a total width of 7.4 km (4.0 NM) at a distance of 24 km (13 NM) from the threshold, thence maintaining a constant
width to the outer boundary of the joint intermediate/final approach area, normally not more than 28 km (15 NM) from
the threshold (see Figures II-1-5-2, II-1-5-3 and II-1-5-4). Where the Annex 14 approach surface penetrates the
approach surfaces and the initial missed approach surface shown in Figure II-1-5-2, the Annex 14 surface is used as the
obstacle clearance surface.
Note 1.— In the event of D becoming greater than 1 060 m the figure of 1 060 m will be used.
Note 2.— The combined intermediate/final approach area corresponds to the extended area for instrument runways
specified in Annex 14.
Note 3.— The length of the final approach area is limited by the convergence of the radar.
5.6.2 Intermediate and final approach obstacle clearances
5.6.2.1 The minimum obstacle clearance above obstacles within the limits of the intermediate and final approach
area shall be as specified herein:
a) from the beginning of intermediate approach, the obstacle clearance surface shall be the horizontal plane whose
height is equal to that of the highest obstacle in the intermediate approach area, to the point where this surface
intersects the plane described under b) hereafter; the obstacle clearance above this plane shall not be less than
150 metres (500 feet) up to a point where the obstacle clearance intersects the plane described under b); and
b) thereafter, within the final approach area, the obstacle clearance surface is contained in a plane inclined at an
angle not greater than 0.6 θ. This plane intersects the horizontal plane through the threshold in a line at right
angles to the runway centre line, at a distance D before the threshold, where:
or
30 H
D= – (D and H in metres)
tan 0.6 θ tan θ
23/11/06