A Pattern A can be flown when the  final approach course  intersects the runway  centerline at less than  a 90° angle, and the  runway is in sight early  enough to establish a  base leg. Circle runway if the runway  becomes visible too late to fly  pattern A. If it is desirable  to land opposite  the direction of  the final app- roach, and the  runway is sighted  in time for a turn  to downwind leg, fly pattern C.  If the runway is  sighted too late  for a turn to  downwind,  fly pattern D. B C D Figure 10-13 .  Circling approaches. performance characteristics of the aircraft. In each instance,  the pilot must consider all factors: airport design, ceiling and  visibility, wind direction and velocity, final approach course  alignment, distance from the final approach fix to the runway,  and ATC instructions. Pilots may not operate an aircraft at any airport below  the authorized MDA or continue an approach below the  authorized DA/DH unless: remaining clear of obstacles. The procedure is shown on the  approach chart in text and graphic form. Since the execution  of a missed approach occurs when the flight deck workload is  at a maximum, the procedure should be studied and mastered  before beginning the approach. When a MAP is initiated, a climb pitch attitude should be  established while setting climb power. Configure the aircraft  for climb, turn to the appropriate heading, advise ATC that  a missed approach is being executed, and request further  clearances. 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 chart. Fly to the MAP at or above  the MDA or DA/DH before beginning a turn. If visual reference is lost while circling-to-land from an  instrument approach, execute the appropriate MAP. Make  the initial climbing turn toward the landing runway and then  maneuver to intercept and fly the missed approach course. A MAP is formulated for each published instrument approach  and allows the pilot to return to the airway structure while  Missed Approaches IAP Minimums 1.  The aircraft is continuously in a position from which  a descent to a landing on the intended runway can be  made at a normal descent rate using normal maneuvers; 2.  The flight visibility is not less than that prescribed for  the approach procedure being used; and 3.  At least one of the following visual references for the  intended runway is visible and identifiable to the pilot: a)  Approach light system b)  Threshold c)  Threshold markings d)  Threshold lights e)  Runway end identifier lights (REIL) f)  Visual approach slope indicator (VASI) g)  Touchdown zone or touchdown zone markings h)  Touchdown zone lights i)  Runway or runway markings j)  Runway lights 1.  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; 2.  Whenever an identifiable part of the airport is not  visible to the pilot during a circling maneuver at or  above MDA; or  3.  When so directed by ATC. Pilots should immediately execute the MAP: 10-21