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

I-3-3-6 Procedures — Aircraft Operations — Volume II
3.3.6.1 General
23/11/06
3.3.6 Turn at a designated TP
A designated TP is selected to allow the aircraft to avoid an obstacle straight ahead. The straight departure criteria
applyuptotheearliestTP.
3.3.6.2 Turn point tolerance
3.3.6.2.1 The longitudinal limits of the TP tolerance are:
a) earliest limit, the end of the turn initiation area (K-line); and
b) latest limit, determined by:
1) K-line plus;
2) TP fix tolerance plus; and
3) flight technical tolerance c, where c is calculated in accordance with 3.3.4 h).
3.3.6.2.2 Where the TP is defined by passage over a navigation aid, the fix tolerance is computed at the elevation
of the DER plus 10 per cent of the distance from the DER to the TP (i.e. allowing for a 10 per cent climb gradient).
Where the TP is defined by a DME distance, the maximum angle that a line joining the TP and the DME may make
with the nominal departure track shall not be more than 23°. (See Section 2, Chapter 2, 2.4.2, “Fixes for VOR or NDB
with DME” and Figure I-2-2-1.)
3.3.6.3 Construction
a) Inner boundary. The inner boundary of the turn area is constructed in accordance with Section 2, Chapter 3,
“Turn area construction”.
b) Outer boundary. The outer boundary of the turn area:
1) begins at the latest TP tolerance (see also Figures I-3-3-11, a) b) c) and d)); and
2) continues along the wind spiral or bounding circles constructed in accordance with Section 2, Chapter 3,
“Turn area construction”; and up to the point (P) where the tangent becomes parallel to the nominal track
after the turn. Examples of turns with track guidance after the turn, flying to or from a facility are provided
in Figures I-3-3-11 c) and d) respectively.
c) For turns more than 90° theareaaftertheturnisconstructedasshownonFigureI-3-3-12.
3.3.6.4 Obstacle clearance in the turn area
In order to ensure that the minimum obstacle clearance in the turn area has been provided, use the following equation to
check the maximum height of an obstacle in the turn area above the elevation of the DER:
Maximum height of obstacle = PDG(dr +do) +H–MOC