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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,
pilots also must fly the procedural track as published.
A procedure turn is the maneuver prescribed to perform a course reversal to establish the aircraft
inbound on an intermediate or final approach course.
The procedure turn or hold- in lieu- of- procedure
turn (PT) is a required maneuver when it is depicted
on the approach chart. However, the procedure turn
or the hold-in-lieu-of-PT is not permitted when the
symbol "No PT" is depicted on the initial segment
being flown, when a RADAR VECTOR to the final
approach course is provided, or when conducting a
timed approach from a holding fix. The altitude prescribed for the procedure turn is a minimum altitude
until the aircraft is established on the inbound
course. The maneuver must be completed within the
distance specified in the profile view. The pilot may
elect to use the procedure turn or hold-in-lieu-of-PT
when it is not required by the procedure, but must
first receive an amended clearance from ATC. When
ATC is Radar vectoring to the final approach course,
or to the Intermediate Fix as may occur with RNAV
standard instrument approach procedures, ATC may
specify in the approach clearance “CLEARED
STRAIGHT-IN (type) APPROACH” to ensure that
the pilot understands that the procedure turn or holdin-lieu-of-PT is not to be flown. If the pilot is uncertain whether ATC intends for a procedure turn or a
straight-in approach to be flown, the pilot shall
immediately request clarification from ATC (14 CFR
Part 91.123).
Approach charts provide headings, altitudes, and distances for a course reversal. Published altitudes are
“minimum” altitudes, and pilots must complete the
maneuver within the distance specified on the profile
500'
4 NM 4 NM 2 NM 2 NM
VORTAC
Length The intermediate segment may NOT
be less than 5 NM nor more than 15 NM in length,
measured along the arc. The OPTIMUM length is
10 NM. A distance greater than 10 NM should not be
used unless an operational requirement justifies the
greater distance.
Width The total width of an arc intermediate
segment is 6 NM on each side of the arc. For obstacle
clearance purposes, this width is divided into a primary
and a secondary area. The primary area extends 4 NM
laterally on each side of the arc segment. The secondary
areas extend 2 NM laterally on each side of the primary
area.
Required Obstacle Clearance (ROC) The ROC
is 1,000 feet for the primary initial segment. The secondary
area ROC starts at the primary ROC surface tapering to
zero at the edges of the secondary area in both initial and
intermediate areas. In the primary area of the intermediate
the ROC is 500 feet.
500'
1,000'
Initial
Segment
500'
Intermediate
Segment
500'
2 NM
2 NM
4 NM
4 NM
Figure 5-28. DME Arc Obstruction Clearance.
5-39
5-40
view (typically within 10 NM). Pilots also are required
to maneuver the aircraft on the procedure turn side of
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Instrument Procedures Handbook (IPH)仪表程序手册下(124)
