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

Appendix B to Chapter 3
REDUCTION OF THE WIDTH OF A STRAIGHT INITIAL APPROACH
AREA AFTER THE IAF AND INTERFACE BETWEEN STRAIGHT
INITIAL APPROACH AREA AND REVERSAL PROCEDURE AREAS
(see Chapter 3, 3.3.2)
1. REDUCTION OF THE WIDTH OF A STRAIGHT INITIAL
APPROACH AREA AFTER THE IAF
1.1 General
Where the initial approach includes a straight segment ending at an intermediate approach fix (IF) defined by a VOR,
NDB or RNAV waypoint, its width at the IF is reduced from the appropriate en-route width to:
a) ± 3.7 km (2.0 NM) at a VOR;
b) ± 4.6 km (2.5 NM) at an NDB; or
c) the calculated area width for an RNAV waypoint.
1.2 Justification
The guidance provided is considered sufficient. The cone effect area radius is:
a) 3.7 km (2.0 NM) for a VOR at 3 000 m (10 000 ft); and
b) 4.6 km (2.5 NM) for an NDB at 5 500 m (18 000 ft).
The area width at the IF for the RNAV case can be calculated. It is assumed that the flight technical tolerance is
diminishing after the aircraft has passed the initial approach fix (IAF).
1.3 VOR cases
1.3.1 The IAF is at a distance of more than 40.5 km (21.9 NM) from the VOR. From a distance of 40.5 km (21.9
NM) from the VOR and up to the VOR, the width of the area on each side of the nominal track is reduced linearly from
9.3 km (5.0 NM) to 3.7 km (2.0 NM), the outer boundary of the area converging at an angle of 7.8° with the nominal
track (Figure I-4-3-App B-1).
I-4-3-App B-1 23/11/06