曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
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
the final approach course. These requirements are
necessary to stay within the protected airspace and
maintain adequate obstacle clearance. [Figure 5-29]
A minimum of 1,000 feet of obstacle clearance is provided in the procedure turn primary area. [Figure 5-30]
In the secondary area, 500 feet of obstacle clearance is
provided at the inner edge, tapering uniformly to zero
feet at the outer edge. The primary and secondary areas
determine obstacle clearance in both the entry and
maneuvering zones. The use of entry and maneuvering
zones provides further relief from obstacles. The entry
zone is established to control the obstacle clearance
prior to proceeding outbound from the procedure turn
fix. The maneuvering zone is established to control
obstacle clearance after proceeding outbound from the
procedure turn fix.
INITIAL APPROACH SEGMENT
The purpose of the initial approach segment is to
provide a method for aligning the aircraft with the
intermediate or final approach segment. This is
accomplished by using a DME arc, a course reversal,
such as a procedure turn or holding pattern, or by
following a terminal route that intersects the final
approach course. The initial approach segment
Obstacle
Primary Area
Secondary Area
Entry Zone
Maneuvering Zone
1000'
1000'
Altitude restricted until
departing IAF outbound.
1,000' Obstacle Clearance
500' — 0' Obstacle Clearance
Figure 5-30. Procedure Turn Obstacle Clearance.
Standard 45° Turn Teardrop Pattern
270°
225°
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：
Instrument Procedures Handbook (IPH)仪表程序手册上(129)
