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less than that prescribed for that aerodrome and the particular
operation (CAR 257).
1.7 Visual Circling or During Non-Precision Approach (NPA)
1.7.1 A circling approach is a visual flight manoeuvre. Each circling situation
is different because of variables such as runway layout,
final approach track, wind velocity and meteorological conditions.
Therefore, there can be no single procedure designed that will
cater for the conduct of a circling approach in every situation. After
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ENR (EN ROUTE) A/L 45 effective 24 NOV 05
initial visual contact, the basic assumption is that the runway environment
(ie, the runway threshold or approach lighting aids or
other markings identifiable with the runway) will be kept in sight
while at MDA for circling (Reference: ICAO Doc 8168).
1.7.2 The information provided by spot heights on IAL charts must be
treated with caution. Spot heights on IAL charts do not necessarily
indicate the highest terrain, or all obstacles in the circling area. In
addition, the charts may not cover all of the circling area. Before
commencing an instrument approach, pilots should familiarise
themselves with the location and altitude of obstacles in the circling
area by studying an appropriate topographic map.
1.7.3 During visual circling or during a NPA, descent below the MDA
may only occur when the pilot:
a. maintains the aircraft within the circling area; and
b. maintains a visibility, along the intended flight path, not less
than the minimum specified on the chart for the procedure; and
c. maintains visual contact with the landing runway environment
(ie, the runway threshold or approach lighting or other
markings identifiable with the runway);
and either
d. by night or day, while complying with a., b. and c. (at an altitude
not less than the MDA), intercepts a position on the downwind,
base or final leg of the landing traffic pattern, and, from this
position, can complete a continuous descent to the landing
threshold using rates of descent and flight manoeuvres which
are normal for the aircraft type and, during this descent, maintains
an obstacle clearance along the flight path not less than
the minimum for the aircraft performance category until the aircraft
is aligned with the landing runway;
or
e. in daylight only, while complying with a., b. and c., maintains visual
contact with obstacles along the intended flight path and
an obstacle clearance not less than the minimum for the aircraft
performance category until the aircraft is aligned with the landing
runway.
Note 1: The concept is as follows:
(1) The pilot maintains visual contact with the landing runway
while the aircraft is circled at MDA to a position within the
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ENR (EN ROUTE) A/L 45 effective 24 NOV 05
traffic pattern that intercepts a normal downwind, base or final approach.
If the MDA is above the downwind height, the aircraft
maintains MDA and downwind spacing until it reaches a position
from which it can descend at normal approach rates to join base
(see Figure 1.)
(2) When daylight exists and obstacles can be seen, the
pilot has the option of descending from MDA from any position within
the circling area while maintaining an obstacle clearance not
less than that required for the aircraft performance category.
Note 2. The pilot should maintain the maximum practical obstacle
clearance. The minimum obstacle clearance requirements
are:
Categories A and B – 300FT;
Categories C and D – 400FT; and
Category E – 500FT.
Note 3. The circling area is determined by drawing an arc centred
on the threshold of each usable runway and joining these arcs by
tangents. The radii are 1.68NM for Category A, 2.66NM for Category
B, 4.20NM for Category C, 5.28NM for Category D and
6.94NM for Category E. Runways less than 1,000M long are not
considered usable for Categories C,D and E.
1.68NM = 3,111M
2.66NM = 4,926M
4.20NM = 7,778M
5.28NM = 9,779M
6.94NM = 12,853M.
1.8 Restrictions on Visual Circling
1.8.1 Where a prominent obstacle or obstacles exist in the visual circling
area outside the final approach and missed approach area, the
sector in which the obstacles are located may be eliminated from
the visual circling area. Sectors which have been eliminated from
the visual circling area are annotated ‘No Circling’.
1.8.2 Visual circling is prohibited in ‘no circling’ sectors by day in less
than VMC and at night.
1.9 Visual Approach Area – Helicopter
1.9.1 Helicopter GPS instrument approach procedures include a Visual
　
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