Two manoeuvres close the PANS-OPS module, and both are flown at the edges of an instrument procedure. The circle-to-land takes over where the previous lesson's final approach could not be aimed at the landing runway: a visual manoeuvre around the aerodrome, flown under an instrument procedure's protection. The holding pattern waits at the other end: the racetrack in the sky that absorbs delay, with entry procedures precise enough to be a favourite exam subject on their own.
Visual manoeuvring: the circle-to-land
Visual manoeuvring, or circling, is the term for the visual phase of flight after completing an instrument approach, which brings the aircraft into position for landing on a runway not suitably located for a straight-in approach: the final track missed the 30-degree alignment window of two lessons ago, or the wind favours another runway. The instrument approach delivers the aircraft to the circling minima in sight of the aerodrome; the rest is flown by eye, inside a protected circling area drawn around the runways.
The protection is category-honest and obstacle-honest. The circling OCA/H is determined for each category of aircraft, because the circling area is drawn from turn radii that grow with approach speed. A prominent obstacle inside the circling area is considered for the circling OCA/H even when it stands outside the final approach and missed approach areas: the whole circle counts, not just the corridor the instruments flew; where such an obstacle dominates one part of the circle, circling in that sector may instead be prohibited and the sector excluded. The MDA/H for circling is then specified at or above the OCA/H: never below the designer's number, with the operational increments on top.
Flying it carries three named conditions. Descent below the circling MDA/H is not made until:
visual reference has been established and can be maintained;
the pilot has the landing threshold in sight;
the required obstacle clearance can be maintained with the aircraft in a position to carry out a landing.
After initial visual contact, the basic assumption of the procedure is that the runway environment is kept in sight (the threshold, the approach lights or other markings identifiable with the runway) while the aircraft manoeuvres at the MDA/H. And there is deliberately no single prescribed circling pattern: runway in use, wind, visibility, the aircraft's speed and the geometry of the aerodrome vary too much for one procedure to fit every situation, so the manoeuvre is left to the pilot's judgement inside the protected area.
One drill covers the day it goes wrong. If visual reference is lost while circling to land, the missed approach of the instrument approach that was flown must be executed, from wherever the aircraft now is. The expected manoeuvre: a climbing turn toward the landing runway, continuing overhead the aerodrome to intercept and fly the missed approach procedure. Turning toward the runway first is the point of the drill: the aerodrome is the one place guaranteed clear of the obstacles the circling area was drawn around, and from overhead it the published missed approach can be joined.
The holding pattern
A holding pattern is the procedure for keeping an aircraft in a block of protected airspace while it waits, and its shape is a racetrack: a holding fix, an inbound track leading to it, a 180-degree turn at the fix onto the outbound leg, and a second 180-degree turn back onto the inbound track. In a standard pattern all turns are to the right; a non-standard pattern turns left. The side of the inbound track the racetrack occupies is the holding side; the other is the non-holding side. The figure names every part.