6-4-1 Application
Separate aircraft longitudinally by requiring them to do one of the
following, as appropriate:
a. Depart at a specified time.
b. Arrive at a fix at a specified time.
PHRASEOLOGY -
CROSS (fix) AT OR BEFORE (time).
CROSS (fix) AT OR AFTER (time).
c. Hold at a fix until a specified time.
d. Change altitude at a specified time or fix.
REFERENCE -
FAAO 7110.65, Altitude Information, paragraph 4-5-7.
6-4-2 Minima on Same, Converging, or Crossing Courses
Separate aircraft on the same, converging, or crossing courses by an interval expressed in time or distance, using the following minima:
{New-98-3 Revised February 26, 1998}
a. When the leading aircraft maintains a speed at least 44 knots
faster than the following aircraft - 5 miles between DME equipped aircraft;
RNAV equipped aircraft using LTD; and between DME and LTD aircraft provided
the DME aircraft is either 10,000 feet or below or outside of 10 miles
from the DME NAVAID, or 3 minutes between other aircraft if, in either
case, one of the following conditions is met:
1. A departing aircraft follows a preceding aircraft which has
taken off from the same or adjacent airport. (See Figure 6-4-1)
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2. A departing aircraft follows a preceding en route aircraft
which has reported over a fix serving the departure airport. (See Figure
6-4-2)
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3. An en route aircraft follows a preceding en route aircraft
which has reported over the same fix. (See Figure 6-4-3).
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{New-98-3 Revised February 26, 1998}
b. When the leading aircraft maintains a speed at least 22 knots faster than the following aircraft - 10 miles between DME equipped aircraft; RNAV equipped aircraft using LTD; and between DME and LTD aircraft provided the DME aircraft is either 10,000 feet or below or outside of 10 miles from the DME NAVAID, or 5 minutes between other aircraft if, in either case, one of the following conditions is exists:
1. A departing aircraft follows a preceding aircraft which has
taken off from the same or an adjacent airport. (See Figure 6-4-4)
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2. A departing aircraft follows a preceding en route aircraft
which has reported over a fix serving the departure airport. (See Figure
6-4-5)
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3. An en route aircraft follows a preceding en route aircraft
which has reported over the same fix. (See Figure 6-4-6)
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c. When an aircraft is climbing or descending through the altitude of another aircraft:
{New-98-3 Revised February 26, 1998}
1. Between DME equipped aircraft; RNAV equipped aircraft using
LTD; and between DME and LTD aircraft provided the DME aircraft is either
10,000 feet or below or outside of 10 miles from the DME NAVAID - 10 miles,
if the descending aircraft is leading or the climbing aircraft is following.
(See Figure 6-4-7 and Figure 6-4-8)
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2. Between other aircraft - 5 minutes, if all of the following conditions are met: (See Figure 6-4-9 and Figure 6-4-10)
(a) The descending aircraft is leading or climbing aircraft
is following.
(b) The aircraft are separated by not more than 4000 feet
when the altitude change started.
(c) The change is started within 10 minutes after a following
aircraft reports over a fix reported over by the leading aircraft or has
acknowledged a clearance specifying the time to cross the same fix.
3. Between RNAV aircraft that are operating along an RNAV route that is eight miles or less in width - 10 miles provided the following conditions are met:
(a) The descending aircraft is leading or the climbing
aircraft is following.
(b) The aircraft were separated by not more than 4,000
feet when the altitude change started.
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{New-98-3 Revised February 26, 1998}
d. When the conditions of subparagraphs a, b, or c cannot be met
- 20 miles between DME equipped aircraft; RNAV equipped aircraft using
LTD; and between DME and LTD aircraft provided the DME aircraft is either
10,000 feet or below or outside of 10 miles from the DME NAVAID; or 10
minutes between other aircraft. (See Figure 6-4-11, Figure 6-4-12, Figure
6-4-13, Figure 6-4-14, Figure 6-4-15, and Figure 6-4-16.)
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{New-98-3 Revised February 26, 1998}
e. Between aircraft, when one aircraft is using DME/LTD and the
other is not - 30 miles if both the following conditions are met: (See
Figure 6-4-17 and Figure 6-4-18)
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{New-98-3 Revised February 26, 1998}
1. The aircraft using DME/LTD derives distance information by
reference to the same NAVAID or waypoint over which the aircraft not using
DME/LTD has reported.
2. The aircraft not using DME/LTD is within 15 minutes of the
NAVAID.
6-4-3 Minima on Opposite Courses
Separate aircraft traveling opposite courses by assigning different
altitudes consistent with the approved vertical separation from 10 minutes
before, until 10 minutes after they are estimated to pass. Vertical separation
may be discontinued after one of the following conditions is met: (See
Figure 6-4-19)
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NOTE -
RNAV route segments that have been expanded in the proximity to reference
facilities for slant range effect are not to be considered "expanded" for
purposes of applying separation criteria in this paragraph.
{New-98-3 Revised February 26, 1998}
a. Both aircraft have reported passing NAVAID's, DME fixes, or
waypoints indicating they have passed each other. (See Figure 6-4-20)
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NOTE -
It is not intended to limit application of this procedure only to aircraft
operating in opposite directions along the same airway or radial. This
procedure may also be applied to aircraft established on diverging airways
or radials of the same NAVAID.
b. Both aircraft have reported passing the same intersection
and they are at least 3 minutes apart.
c. Two RNAV aircraft have reported passing the same position and
are at least 8 miles apart if operating along a route that is 8 miles or
less in width; or 18 miles apart if operating along an expanded route;
except that 30 miles shall be applied if operating along that portion of
any route segment defined by a navigation station requiring extended usable
distance limitations beyond 130 miles.
d. An aircraft utilizing RNAV and an aircraft utilizing VOR have
reported passing the same position and the RNAV aircraft is at least 4
miles beyond the reported position when operating along a route that is
8 miles or less in width; 9 miles beyond the point when operating along
an expanded route; except that 15 miles shall be applied if operating along
that portion of any route segment defined by a navigation station requiring
extended usable distance limitation beyond 130 miles; or 3 minutes apart
whichever is greater.
{New-98-3 Revised February 26, 1998}
When pilots of aircraft on the same course in direct radio communication with each other concur, you may authorize the following aircraft to maintain longitudinal separation of 10 minutes; or 20 miles between DME equipped aircraft; RNAV equipped aircraft using LTD; and between DME and LTD aircraft provided the DME aircraft is either 10,000 feet or below or outside of 10 miles from the DME NAVAID.
PHRASEOLOGY -
MAINTAIN AT LEAST ONE ZERO MINUTES/TWO ZERO MILES SEPARATION FROM (ident).
6-4-5 RNAV Aircraft Along VOR Airways/Routes
Advise the pilot to use DME distances when applying DME separation to an RNAV aircraft operating along VOR airways/routes.
PHRASEOLOGY -
USE DME DISTANCES.
NOTE -
Along track distance derived from area navigation devices having slant
range correction will not coincide with the direct DME readout.