From PANSOPS Part 1 Section 6 Chapter 1
1.4 ENTRY
Note.— Variations of the basic procedure for local conditions may be authorized by States after appropriate consultation with the operators concerned.
1.4.1 The entry into the holding pattern shall be according to heading in relation to the three entry sectors shown in Figure I-6-1-2, recognizing a zone of flexibility of 5° on either side of the sector boundaries.