From my notes on PANS-OPS: Caution they may be out of date:
The OCA/H for circling shall not be less than the OCA/H calculated for the instrument approach procedure leading to the circling manoeuvre.
There are further two separate requirements to be fulfilled: Both requirements are coupled to aircraft category.
Minimum obstacle clearance, MOC (ft)
A 295
B 295
C 394
D 394
Lowest permissible OCH (ft)
A 394
B 492
C 591
D 689
For TERPS: - The circling MDA must not be above the FAF altitude or below the straight-in MDA. The minimum values are:-
Aircraft Cat / lowest height above airfield / Vis
A 350 ft 1 nm
B 400 ft 1 nm
C 500 ft 1.25 nm
D 550 ft 2 nm
Don’t forget to correct all altitudes for temperature error.
Note the significant differences in the circling protected area defined by arcs centered on each runway threshold.
PANS-OPS Cat / nm / max speed / TERPS / nm
A 1.68 / 100 / 1.3
B 2.66 / 135 / 1.5
C 4.2 / 180 / 1.7
D 5.28 / 205 / 2.3
If you use the incorrect area i.e. TERPS vs PANS-OPS (5.28 nm vs 2.3 nm) then see the
BUSAN accident report.
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Unless specifically authorized everything else is forbidden.