AIM

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Arrival Procedures

e. Published Approach Minimums.

Approach

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

stepdown 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minimums will not be published.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:

1.

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.

2.

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

maneuvering must be considered when circling to

land.

3.

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.

REFERENCE

−

AC 90

−66A, Recommended Standards Traffic patterns for Aeronautical

Operations at Airports without Operating Control Towers.

4.

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.

5

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4

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21. Missed Approach

a.

When a landing cannot be accomplished, advise

ATC and, upon reaching the missed approach point

defined on the approach procedure chart, the pilot

must comply with the missed approach instructions

for the procedure being used or with an alternate

missed approach procedure specified by ATC.

b.

Obstacle protection for missed approach is

predicated on the missed approach being initiated at

the decision altitude/height (DA/H) or at the missed

approach point and not lower than minimum descent

altitude (MDA). A climb gradient of at least 200 feet

per nautical mile is required, (except for Copter

approaches, where a climb of at least 400 feet per

nautical mile is required), unless a higher climb

gradient is published in the notes section of the

approach procedure chart. When higher than standard

climb gradients are specified, the end point of the

non−standard climb will be specified at either an

altitude or a fix. Pilots must preplan to ensure that the

aircraft can meet the climb gradient (expressed in feet

per nautical mile) required by the procedure in the

event of a missed approach, and be aware that flying

at a higher than anticipated ground speed increases

the climb rate requirement (feet per minute). Tables

for the conversion of climb gradients (feet per

nautical mile) to climb rate (feet per minute), based

on ground speed, are included on page D1 of the U.S.

Terminal Procedures booklets. Reasonable buffers

are provided for normal maneuvers. However, no