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

Foreword (xvii)
2.2.4 The precision approach criteria were expanded to MLS category I, II and III in 1994 and GBAS category I
in 2004.
2.2.5 Section 2 contains the non-precision approach criteria. The obstacle clearance criteria for non-precision
approaches, as amended by Amendment 13, have not been developed to the same degree of sophistication as the
precision approach obstacle clearance criteria because the level of safety generally associated with the higher operating
minima of non-precision approach procedures is already considered to be acceptable. The procedures, therefore,
continue to be based upon available experience and the judgements of experts. They, however, were amended to
provide a high degree of flexibility designed to assist the procedures specialist in obtaining the maximum operational
advantage compatible with safety.
2.2.6 Based mainly on the experience gained by some States during trial application of the new criteria and as a
result of the ICAO PANS-OPS workshop series held from 1980-1984, the criteria were amended twice (Amendments 1
and 4). The changes fall into three general categories as follows:
— editorial amendments to ease the understanding of the criteria
— simplification of calculations which have proved, in practice, to contain a high error potential
— removal of discrepancies which could have made the document difficult to apply and operationally penalizing.
Amendment 1 also aligned the presentation of units with Annex 5, Fourth Edition.
2.2.7 Section 3 contains the criteria for enroute operations for VOR and NDB. These criteria were added to the
PANS-OPS in 1996. In 2004 simplified criteria were added to allow for less time consuming effort in large airspaces.
2.2.8 Section 4 contains the criteria for holding procedures. Holding procedures were first developed by the
Operations Division in 1949 and issued in 1951. A major revision of these procedures was accomplished in 1965 as a
result of the work of the Holding Procedures Panel (HOP). The material developed by the HOP was subsequently
divided in 1979 and that part of the material concerning holding procedures was incorporated in PANS-OPS, Volume I
and the material covering the construction of holding procedures incorporated in Volume II.
2.2.9 In 1982 as a result of the work of the Obstacle Clearance Panel (OCP) new material and changes to the old
material were introduced concerning VOR/DME holding, use of holding procedures by helicopters, buffer areas and
entry procedures. In 1986, changes were introduced concerning the VOR TO/FROM indication error zone, the
minimum usable DME distance and holding speeds, particularly above 4 250 m (14 000 ft).
2.3 Part III — RNAV procedures and satellite based procedures
2.3.1 The first RNAV departure procedures were incorporated in PANS-OPS with the introduction of area
navigation (RNAV) departure procedures based on VOR/DME in 1993 arising from the Ninth Meeting of the Obstacle
Clearance Panel. Departure procedures for DME/DME, basic GNSS followed in 1998, Procedures for RNP and SBAS
departure procedures were introduced in 2001 and 2004 respectively.
Arrival and approach procedures
2.3.2 Similar to the departure procedures, Area navigation (RNAV) criteria for instrument approach procedures
were introduced for VOR/DME in 1993. Approach procedures for DME/DME, basic GNSS followed in 1998.
Procedures for RNP 0.3 were introduced in 2001. As a result of a CFIT safety initiative, Baro-VNAV criteria based on
DME/DME or Basic GNSS sensors were included in the document in 2001.
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