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

II-1-5-4 Procedures — Aircraft Operations — Volume II
23/11/06
98 H
D= tan 0.6 θ – tan θ
where: θ = nominal glide path angle;
0.6 θ = worst assumed descent path angle; and
(D and H in feet)
H = height of the nominal descent path over the threshold.
5.6.2.2 The final approach OCA/H is obtained by adding the values for pressure altimeter from Section 1,
Chapter 1, Table II-1-1-2 to the highest obstruction penetrating the plane defined in 5.6.2.1 b), or to the highest
obstruction in the initial missed approach area, whichever is higher. (See Figure II-1-5-5.) It must also assure missed
approach obstacle clearance is provided (see 5.7.2.2).
5.7 MISSED APPROACH AREA AND OBSTACLE CLEARANCE
5.7.1 Missed approach area
The initial phase of the missed approach area starts at the MAPt which is at the end of the final approach area (i.e. at a
distance D before the threshold). The initial phase continues from there with a constant width of 600 m, there being
300 m on either side of the runway centre line, to a distance of not less than 900 m nor normally, more than 1 800 m
beyond the threshold. At this point, the intermediate phase of the missed approach area commences. This intermediate
phase is an area symmetrical about the missed approach track extending a sufficient distance to ensure that an aircraft
climbing at a gradient of 2.5 per cent has reached an altitude at which a major turn can be initiated, acceleration may
commence or obstacle clearances (such as for en route or holding) become effective. (See Part I, Section 4, Chapter 6,
6.2.2, “Intermediate phase”). The width of the intermediate phase of the missed approach area is 600 m until it reaches
1 800 m beyond the threshold or reaches the runway end, whichever is the least, then widening with a splay of 15° on
either side. The final phase shall be in accordance with criteria contained in Part I, Section 4, Chapter 6. Where positive
radar guidance is provided throughout the missed approach procedure, the splay may be reduced to a minimum of 10°.
Criteria for additional track guidance is contained in Part I, Section 4, Chapter 6, 6.3.2.3, “Additional track guidance”.
Note.— In determining the missed approach area for a particular runway, the following considerations are
pertinent:
a) the maximum distance from the threshold of 1 800 m for the commencement of the assumed gradient of 2.5 per
cent may be unduly restrictive for certain aircraft operations and where this is so, this point may be varied to
suit the conditions existing, but in any case the commencing point should not be less than 900 m from the
threshold; and
b) the angular deviations of 10° and 15° allow for pilot ability to maintain track during missed approach with or
without radar guidance.
5.7.2 Missed approach obstacle clearance
5.7.2.1 The minimum vertical clearance above all obstacles in the missed approach area shall be 30 m (98 ft).
5.7.2.2 The OCA/H for the intermediate phase of the missed approach area is determined by assuming a missed
approach climb gradient that clears all obstacles in the intermediate phase of the missed approach area by at least 30 m
(98 ft). This OCA/H for missed approach shall be the height at which a 2.5 per cent plane, passing at least 30 m (98 ft)