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

Chapter 1
DEPARTURE PROCEDURES
1.1 GENERAL
1.1.1 Application
1.1.1.1 This chapter describes the departure criteria for RNAV and RNP procedures.
1.1.1.2 The general criteria of Part I, Section 3 and Part III, Sections 1 and 2 as amplified or modified by the
criteria in this chapter apply to RNAV and RNP departure procedures.
1.1.2 Secondary areas
The principle of secondary areas applies to straight segments (see Part I, Section 2, Chapter 1, 1.2 and 1.3). Secondary
areas are limited to the part of the procedure where the total width of the primary area is at least equal to the area semiwidth
at the first waypoint, as shown in Table III-3-1-1. See Figure III-3-1-1.
1.1.3 Minimum segment length
Minimum segment length distances are listed in the tables in Section 2, Chapter 1. For construction of the average
flight path see Part I, Section 3, Appendix to Chapter 3.
1.1.4 Area widths
1.1.4.1 For RNAV based on VOR/DME, DME/DME or GNSS the total area width results from joining the
various area widths at the relevant fixes. For the calculation of area widths and the underlying tolerances involved in
these calculations, see the paragraph entitled “XTT, ATT and area semi-width” in Section 1 for the appropriate sensor.
These are:
a) VOR/DME, Section 1, Chapter 4, 4.5;
b) DME/DME, Section 1, Chapter 3, 3.6;
c) basic GNSS, Section 1, Chapter 2, 2.5; and
d) SBAS, Section 1, Chapter 5, 5.1.2.
1.1.4.2 For RNAV based on RNP when the promulgated RNP value decreases in a point of a procedure the total
area width as defined in Section 1, Chapter 7, 7.5, “XTT, ATT and area semi-width” decreases from the initial value to
the final value with a convergence angle of 30° each side of the axis.
III-3-1-1 23/11/06