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

III-3-6-18 Procedures — Aircraft Operations — Volume II
23/11/06
6.7 GBAS CAT I WITH OFFSET AZIMUTH FINAL APPROACH TRACK ALIGNMENT
6.7.1 Use of GBAS Cat I with offset azimuth final approach track alignment
In certain cases it may not be physically practicable to align the final approach track with the runway centre line
because of obstacle problems. An offset final approach track shall not be established as a noise abatement measure. The
final approach track shall intersect the runway extended centre line:
a) at an angle not exceeding 5°; and
b) at a point where the nominal glide path reaches a height called intercept height of at least 55 m (180 ft) above
threshold elevation. The procedure shall be annotated: “final approach track offset... degrees” (tenth of degrees).
The general arrangement is shown in Figure III-3-6-18.
The provisions contained in 6.1 to 6.6 apply except that:
6.7.2 Obstacle clearance criteria
a) all the obstacle clearance surfaces and calculations are based on a fictitious runway aligned with the final
approach track. This fictitious runway has the same length and the same landing threshold elevation as the real
one. The FTP is analogous to the LTP for aligned procedures. The GBAS course width at the FTP is the same
as at the LTP. The DCP is located 15 m (50 ft) above the FTP; and
b) the OCA/H for this procedure shall be at least: intercept altitude/height + 20 m (66 ft).
6.8 PROMULGATION
6.8.1 General
The general criteria in Part I, Section 4, Chapter 9, 9.5 apply. The instrument approach chart for a GBAS approach
procedure shall be identified by the title GLS Rwy XX. If more than one GBAS approach is published for the same
runway, the Duplicate Procedure Title convention shall be applied, with the approach having the lowest minima being
identified as GLS Z Rwy XX.
6.8.2 Promulgation of OCA/H values
Promulgation of OCA/H for GBAS Cat I approach procedures. The OCA or OCH values, as appropriate, shall be
promulgated for those categories of aircraft for which the procedure is designed. The values shall be based on the
following standard conditions:
a) Cat I flown with pressure altimeter;
b) standard aircraft dimensions (see 6.1.3); and
c) 2.5 per cent missed approach climb gradient.
Additional values of OCA/H may be agreed between operators and the appropriate authority and promulgated, on
the basis of evidence supporting the modifications defined in 6.4.8.7.