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higher approach category, the minimums for the appropriate higher category must be used. Emergency returns at
weights in excess of maximum certificated landing
weight, approaches made with inoperative flaps, and
approaches made in icing conditions for some airplanes
are examples of situations that can necessitate the use of a
higher approach category minima.
Circling approaches conducted at faster-than-normal
straight-in approach speeds also require a pilot to consider
the larger circling approach area, since published circling
minimums provide obstacle clearance only within the
appropriate area of protection, and is based on the
approach category speed. [Figure 5-3] The circling
approach area is the obstacle clearance area for airplanes
maneuvering to land on a runway that does not meet the
criteria for a straight-in approach. The size of the circling
area varies with the approach category of the airplane, as
shown in Figure 5-3. A minimum of 300 feet of obstacle
clearance is provided in the circling segment. Pilots
should remain at or above the circling altitude until the
airplane 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 and using normal maneuvers.
Since an approach category can make a difference in the
approach and weather minimums and, in some cases, prohibit flight crews from initiating an approach, the
approach speed should be calculated and the effects on the
approach determined and briefed in the preflight planning
phase, as well as reviewed prior to commencing an
approach.
OPERATIONAL CONSIDERATIONS
Most commercial operators dictate standard procedures
for conducting instrument approaches in their FAA
approved manuals. These standards designate company
callouts, flight profiles, configurations, and other
specific duties for each cockpit crewmember during the
conduct of an instrument approach.
APPROACH CHART FORMATS
Beginning in February 2000, NACO began issuing the
current format for IAPs. This chart was developed by the
Department of Transportation, Volpe National
Transportation Systems Center and is commonly referred
to as the Pilot Briefing Information format. The NACO
CIRCLING
APPROACH AREA
RADII ( ) DEFINING SIZE
OF AREAS, VARY WITH THE
APPROACH CATEGORY
Approach Category
A
B
C
D
E
Radius (Miles)
1.3
1.5
1.7
2.3
4.5
Figure 5-3. Construction of Circling Approach Area.
5-8
chart format is presented in a logical order, facilitating
pilot briefing of the procedures. [Figure 5-4]
APPROACH CHART NAMING CONVENTIONS
Individual NACO charts are identified on both the top and
the bottom of the page by their procedure name (based on
the NAVAIDs required for the final approach), runway
served, and airport location. The identifier for the airport
is also listed immediately after the airport name, as shown
in Figure 5-5.
There are several types of approach procedures that
may cause some confusion for flight crews unfamiliar with the naming conventions. Although specific
information about each type of approach will be covered later in this chapter, here are a few procedure
names that can cause confusion.
STRAIGHT-IN PROCEDURES
When two or more straight-in approaches with the
same type of guidance exist for a runway, a letter suffix
is added to the title of the approach so that it can be
more easily identified. These approach charts start with
the letter Z and continue in reverse alphabetical order.
For example, consider the RNAV (GPS) Z RWY 13C
and RNAV (RNP) Y RWY 13C approaches at Chicago
Midway International Airport. [Figure 5-6] Although
these two approaches can both be flown with GPS to
the same runway they are significantly different, e.g.,
one is a “SPECIAL AIRCRAFT & AIRCREW
AUTHORIZATION REQUIRED (SAAAR); one has
circling minimums and the other does not; the minimums are different; and the missed approaches are not
the same. The approach procedure labeled Z will have
lower landing minimums than Y (some older charts
may not reflect this). In this example, the LNAV MDA
for the RNAV (GPS) Z RWY 13C has the lowest minimums of either approach due to the differences in the
final approach ROC evaluation. This convention also
eliminates any confusion with approach procedures
labeled A and B, where only circling minimums are
published. The designation of two area navigation
(RNAV) procedures to the same runway can occur
when it is desirable to accommodate panel
mounted global positioning system (GPS)
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Instrument Procedures Handbook (IPH)仪表程序手册下(104)
