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

Chapter 6
PRECISION APPROACH PROCEDURES — GBAS
6.1 INTRODUCTION
6.1.1 Application
The GBAS criteria in this chapter are based on ILS criteria and are related to the ground and airborne equipment
performance and integrity required to meet the Category I operational objectives described in Annex 10. An illustration
of the specific definitions used in this chapter is given in Figure III-3-6-1.
Note.— While specific GBAS Category I criteria are in preparation, the criteria contained in this chapter are based
on an ILS Category I equivalency method. Development of Annex 10 requirements for Category II and III approaches
is in progress; pending their finalization, procedure design criteria will be made available.
6.1.2 Procedure construction
The procedure from en route to the GBAS final approach segment and in the final missed approach phase conforms
with the general criteria. The differences are found in the physical requirements for the GBAS precision segment which
contains the final approach segment as well as the initial and intermediate phases of the missed approach segment.
These requirements are related to the performance of the GBAS Cat I system.
6.1.3 Standard conditions
The following list contains the standard assumptions on which procedures are developed. Provisions are made for
adjustments where appropriate. Adjustments are mandatory when conditions differ adversely from standard conditions
and are optional when so specified (see 6.4.8.7, “Adjustment of OAS constants”).
a) Maximum aircraft dimensions are assumed to be the following:
Aircraft category Wing span
Vertical distance between the flight
paths of the wheels and the GBAS antenna
(m)
H 30 3
A, B 60 6
C, D 65 7
DL 80 8
Note 1.— OCA/H for Cat DL aircraft is published when necessary.
III-3-6-1 23/11/06