曝光台 注意防骗
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pilot, auto-brakes, auto-throttles,
speed brakes, reverse thrust, etc.
Aircraft specific missed approach
considerations/techniques
Additional items/duties pertaining to
the situation (CAT II/III [auto-land],
inoperative equipment, etc.)
Transfer of flight controls
Communications
Figure 5-26. Approach Chart Briefing Sequence.
5-38
TERMINAL ROUTES
In cases where the IAF is part of the en route structure
and feeder routes are not required, a transition or terminal route is still needed for aircraft to proceed from the
IAF to the intermediate fix (IF). These routes are initial
approach segments because they begin at the IAF. Like
feeder routes, they are depicted with course, minimum
altitude, and distance to the IF. Essentially, these routes
accomplish the same thing as feeder routes but they
originate at an IAF, whereas feeder routes terminate at
an IAF.
DME ARCS
DME arcs also provide transitions to the approach
course, but DME arcs are actually approach segments
while feeder routes, by definition, are not. When
established on a DME arc, the aircraft has departed
the en route phase and has begun the approach and is
maneuvering to enter an intermediate or final segment of the approach. DME arcs may also be used as
an intermediate or a final segment, although they are
extremely rare as final approach segments.
An arc may join a course at or before the IF. When joining a course at or before the IF, the angle of intersection
of the arc and the course is designed so it does not
exceed 120°. When the angle exceeds 90°, a radial that
provides at least 2 NM of lead shall be identified to
assist in leading the turn on to the intermediate course.
DME arcs are predicated on DME collocated with a
facility providing omnidirectional course information,
such as a VOR. A DME arc cannot be based on an ILS
or LOC DME source because omnidirectional course
information is not provided.
Required obstruction clearance (ROC) along the arc
depends on the approach segment. For an initial
approach segment, a ROC of 1,000 feet is required in
the primary area, which extends to 4 NM on either side
of the arc. For an intermediate segment primary area
the ROC is 500 feet. The initial and intermediate segment secondary areas extend 2 NM from the primary
boundary area edge. The ROC starts at the primary
area boundary edge at 500 feet and tapers to zero feet at
the secondary area outer edge. [Figure 5-28]
COURSE REVERSAL
Some approach procedures do not permit straight-in
approaches unless pilots are being radar vectored. In
these situations, pilots will be required to complete a
procedure turn (PT) or other course reversal, generally
within 10 NM of the PT fix, to establish the aircraft
inbound on the intermediate or final approach segment.
If Category E airplanes are using the PT or there is a
descent gradient problem, the PT distance available can
be as much as 15 NM. During a procedure turn, a
maximum speed of 200 knots indicated airspeed
Flight Path
MAP
1,000'
500'
250'
1,000'
IAF IF
FAF
Obstacle Runway
Initial Intermediate Final
Missed
Approach
Re-Enter
Enroute Phase
Feeder Route
Feeder Route
IAF
IF
FAF
PROFILE VIEW
PLAN VIEW
PROJECTED VIEW
Figure 5-27. Approach Segments and Obstacle Clearance.
(KIAS) should be observed from first crossing the
course reversal IAF through the procedure turn
maneuver to ensure containment within the obstruction clearance area. Unless a holding pattern or
teardrop procedure is published, the point where
pilots begin the turn and the type and rate of turn are
optional. If above the procedure turn minimum
altitude, pilots may begin descent as soon as they
cross the IAF outbound.
The 45° procedure turn, the racetrack pattern (holding
pattern), the teardrop procedure turn, or the 80°/260°
course reversal are mentioned in the AIM as acceptable
variations for course reversal. When a holding pattern
is published in place of a procedure turn, pilots must
make the standard entry and follow the depicted pattern
to establish the aircraft on the inbound course.
Additional circuits in the holding pattern are not necessary or expected by ATC if pilots are cleared for the
approach prior to returning to the fix. In the event additional time is needed to lose altitude or become better
established on course, pilots should advise ATC and
obtain approval for any additional turns. When a
teardrop is depicted and a course reversal is required,
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Instrument Procedures Handbook (IPH)仪表程序手册上(128)
