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c.  Straight

in Minimums

 are shown on the IAP 

when the final approach course is within 30 degrees 
of the runway alignment (15 degrees for GPS IAPs) 
and a normal descent can be made from the IFR 
altitude shown on the IAP to the runway surface. 
When either the normal rate of descent or the runway 
alignment factor of 30 degrees (15 degrees for GPS 
IAPs) is exceeded, a straight

in minimum is not 

published and a circling minimum applies. The fact 
that a straight

in minimum is not published does not 

preclude pilots from landing straight

in if they have 

the active runway in sight and have sufficient time to 
make a normal approach for landing. Under such 
conditions and when ATC has cleared them for 
landing on that runway, pilots are not expected to 
circle even though only circling minimums are 
published. If they desire to circle, they should advise 

d.  Side

Step Maneuver Minimums. 


minimums for a side

step maneuver to the adjacent 

runway will normally be higher than the minimums 
to the primary runway. 

e. Published Approach Minimums. 


minimums are published for different aircraft 
categories and consist of a minimum altitude (DA, 
DH, MDA) and required visibility. These minimums 
are determined by applying the appropriate TERPS 
criteria. When a fix is incorporated in a nonprecision 
final segment, two sets of minimums may be 
published: one for the pilot that is able to identify the 
fix, and a second for the pilot that cannot. Two sets of 
minimums may also be published when a second 
altimeter source is used in the procedure. When a 
nonprecision procedure incorporates both a step-
down fix in the final segment and a second altimeter 
source, two sets of minimums are published to 
account for the stepdown fix and a note addresses 
minimums for the second altimeter source. 

f.  Circling Minimums. 

In some busy terminal 

areas, ATC may not allow circling and circling 
minimums will not be published. Published circling 
minimums provide obstacle clearance when pilots 
remain within the appropriate area of protection. 
Pilots should remain at or above the circling altitude 

until the aircraft is continuously 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. Circling may require maneuvers at low 
altitude, at low airspeed, and in marginal weather 
conditions. Pilots must use sound judgment, have an 
indepth knowledge of their capabilities, and fully 
understand the aircraft performance to determine the 
exact circling maneuver since weather, unique airport 
design, and the aircraft position, altitude, and 
airspeed must all be considered. The following basic 
rules apply: 


Maneuver the shortest path to the base or 

downwind leg, as appropriate, considering existing 
weather conditions. There is no restriction from 
passing over the airport or other runways. 


It should be recognized that circling 

maneuvers may be made while VFR or other flying 
is in progress at the airport. Standard left turns or 
specific instruction from the controller for maneuver-
ing must be considered when circling to land. 


At airports without a control tower, it may be 

desirable to fly over the airport to observe wind and 
turn indicators and other traffic which may be on the 
runway or flying in the vicinity of the airport. 



AC 90

66A, Recommended Standards Traffic patterns for Aeronautical 

Operations at Airports without Operating Control Towers. 


The missed approach point (MAP) varies 

depending upon the approach flown. For vertically 
guided approaches, the MAP is at the decision 
altitude/decision height. Non

vertically guided and 

circling procedures share the same MAP and the pilot 
determines this MAP by timing from the final 
approach fix, by a fix, a NAVAID, or a waypoint. 
Circling from a GLS, an ILS without a localizer line 
of minima or an RNAV (GPS) approach without an 
LNAV line of minima is prohibited. 

g. Instrument Approach at a Military Field. 

When instrument approaches are conducted by civil 
aircraft at military airports, they must be conducted in 
accordance with the procedures and minimums 
approved by the military agency having jurisdiction 
over the airport. 

Arrival Procedures