CAT II and III approaches call for different visibility requirements as prescribed by the Administrator. In addition, according to Part 91, the aircraft must continuously be in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers, and for operations conducted under Part 121 or 135, unless that descent rate will allow touchdown to occur within the touchdown zone of the runway of intended landing. The primary reason, of course, is that the required flight visibility prescribed in the IAP being used does not exist or the required visual references for the runway cannot be seen upon arrival at the DA, DH or MAP. Many reasons exist for executing a missed approach.

FAA versus ICAO Differences for more about this. Realize too that your first turn following a circling approach may not necessarily be toward the approach runway when flying internationally. If you are doing an approach that has a simultaneous approach to a parallel runway, there is an excellent chance the published missed approach procedure is not what is in your box. Things have gotten better with modern day flight management systems, you just need to make sure the FMS is programmed to do what you want and what ATC expects. Missed approach instructions will be provided prior to starting the final approach of either an ASR or PAR approach. This time determines when you report and execute a missed approach if you do not have applicable minimums. The airport diagram on the IAP shows the time from the facility to the missed approach at various groundspeeds, which you must determine from airspeed, wind, and distance values. When the FAF is not located on the field, the missed approach procedure will specify the distance from the facility to the MAP. The missed approach procedures are related to the location of the FAF.Whenever an identifiable part of the airport is not visible to the pilot during a circling maneuver at or above MDA.Whenever the requirements for operating below DA/DH or MDA are not met when the aircraft is below MDA, or upon arrival at the MAP and at any time after that until touchdown.Pilots should immediately execute the missed approach procedure:.You should make the initial climbing turn toward the landing runway and then maneuver to intercept and fly the missed approach course. If visual reference is lost while circling-to-land from an instrument approach, execute the appropriate MAP.If the missed approach is initiated prior to reaching the MAP, unless otherwise cleared by ATC, continue to fly the IAP as specified on the approach plate to the MAP at or above the MDA or DA/DH before beginning a turn.You should configure the aircraft for climb, turn to the appropriate heading, advise ATC that you are executing a missed approach, and request further clearances. When a MAP is initiated, a climb pitch attitude should be established while setting climb power.Since the execution of a missed approach occurs when your cockpit workload is at a maximum, the procedure should be studied and mastered before beginning the approach. The procedure is shown on the approach chart in text and graphic form. A missed approach procedure is formulated for each published instrument approach and allows the pilot to return to the airway structure while remaining clear of obstacles.

Icao doc 8168 2018