4. En Route Procedures
4.1 Air Route Traffic Control Center (ARTCC)
An ARTCC is a facility established to provide air
traffic control service to aircraft operating on
instrument flight rule (IFR) flight plans within
CONTROLLED AIRSPACE and principally during
the en route phase of flight. When equipment
capabilities and controller workload permit, certain
advisory/assistance services may be provided to
visual flight rule (VFR) aircraft.
4.2 ARTCC Communications
4.2.1 Direct Communications, Controllers and
Pilots
4.2.1.1 ARTCCs are capable of direct communications
with IFR air traffic on certain frequencies.
Maximum communications coverage is possible
through the use of Remote Center Air/Ground
(RCAG) sites comprised of very high frequency
(VHF) and ultra high frequency (UHF) transmitters
and receivers. These sites are located throughout the
U.S. Although they may be several hundred miles
away from the ARTCC, they are remoted to the
various centers by land lines or microwave links. As
IFR operations are expedited through the use of direct
communications, pilots are requested to use these
frequencies strictly for communications pertinent to
the control of IFR aircraft. Flight plan filing, en route
weather, weather forecasts, and similar data should be
requested through Flight Service Stations, company
radio, or appropriate military facilities capable of
performing these services.
4.2.1.2 An ARTCC is divided into sectors. Each
sector is handled by one or a team of controllers and
has its own sector discrete frequency. As a flight
progresses from one sector to another, the pilot is
requested to change to the appropriate sector discrete
frequency.
4.2.1.3 Controller Pilot Data Link Communications
(CPDLC) is a system that supplements air/ground
voice communications. As a result, it expands
two-way air traffic control air/ground communications
capabilities. Consequently, the air traffic
system’s operational capacity is increased and any
associated air traffic delays become minimized. A
related safety benefit is that pilot/controller read-
back and hear-back errors will be significantly
reduced. The CPDLC’s principal operating criteria
are:
a) Voice remains the primary and controlling
air/ground communications means.
b) Participating aircraft will need to have the
appropriate CPDLC avionics equipment in order to
receive uplink or transmit downlink messages.
c) CPDLC Build 1 offers four ATC data link
services. These are altimeter setting (AS), transfer of
communications (TC), initial contact (IC), and menu
text messages (MT).
1) Altimeter settings are usually transmitted
automatically when a CPDLC session and eligibility
has been established with an aircraft. A controller
may also manually send an altimeter setting message.
NOTE-
When conducting instrument approach procedures, pilots
are responsible to obtain and use the appropriate altimeter
setting in accordance with 14 CFR Section 97.20. CPDLC
issued altimeter settings are excluded for this purpose.
2) Initial contact is a safety validation transaction
that compares a pilot’s initiated altitude
downlink message with an aircraft’s ATC host
computer stored altitude. If an altitude mismatch is
detected, the controller will verbally provide
corrective action.
3) Transfer of communications automatically
establishes data link contact with a succeeding sector.
4) Menu text transmissions are scripted nontrajectory
altering uplink messages.
NOTE-
Initial use of CPDLC will be at the Miami Air Route Traffic
Control Center (ARTCC). Air carriers will be the first
users. Subsequently, CPDLC will be made available to all
NAS users. Later versions will include trajectory altering
services and expanded clearance and advisory message
capabilities.
4.2.2 ATC Frequency Change Procedures
4.2.2.1 The following phraseology will be used by
controllers to effect a frequency change:
EXAMPLE-
(Aircraft identification) CONTACT (facility name or
location name and terminal function) (frequency) AT (time,
fix, or altitude).
NOTE-
Pilots are expected to maintain a listening watch on the
transferring controller’s frequency until the time, fix, or
altitude specified. ATC will omit frequency change
restrictions whenever pilot compliance is expected upon
receipt.
4.2.2.2 The following phraseology should be
utilized by pilots for establishing contact with the
designated facility:
a) When operating in a radar environment:
1) On initial contact, the pilot should inform the
controller of the aircraft’s assigned altitude preceded
by the words “level,” or “climbing to,” or
“descending to,” as appropriate; and the aircraft’s
present vacating altitude, if applicable.
EXAMPLE-
1. (Name) CENTER, (aircraft identification), LEVEL
(altitude or flight level).
2. (Name) CENTER, (aircraft identification), LEAVING
(exact altitude or flight level), CLIMBING TO OR
DESCENDING TO (altitude or flight level).
NOTE-
Exact altitude or flight level means to the nearest 100 foot
increment. exact altitude or flight level reports on initial
contact provide ATC with information required prior to
using Mode C altitude information for separation
purposes.
b) When operating in a nonradar environment:
1) On initial contact, the pilot should inform the
controller of the aircraft’s present position, altitude
and time estimate for the next reporting point.
EXAMPLE-
(Name) CENTER, (aircraft identification), (POSITION),
(altitude), ESTIMATING (reporting point) at (time).
2) After initial contact, when a position report
will be made, the pilot should give the controller a
complete position report.
EXAMPLE-
(Name) CENTER, (aircraft identification), (position),
(time), (altitude), (type of flight plan), (ETA and name of
next reporting point), (the name of the next succeeding
reporting point), AND (remarks).
REFERENCE-
AIP, Position Reporting, Paragraph 6.
4.2.2.3 At times controllers will ask pilots to verify
the fact that they are at a particular altitude. The
phraseology used will be: “VERIFY AT (altitude).”
In climbing/descending situations, controllers may
ask pilots to “VERIFY ASSIGNED ALTITUDE AS
(altitude).” Pilots should confirm that they are at the
altitude stated by the controller or that the assigned
altitude is correct as stated. If this is not the case, they
should inform the controller of the actual altitude
being maintained or the different assigned altitude.
CAUTION-
Pilots should not take action to change their actual
altitude or different assigned altitude to that stated in the
controller’s verification request unless the controller
specifically authorizes a change.
4.2.3 ARTCC Radio Frequency Outage.
ARTCC’s normally have at least one back-up radio
receiver and transmitter system for each frequency
which can usually be pressed into service quickly
with little or no disruption of ATC service.
Occasionally, technical problems may cause a delay
but switchover seldom takes more than 60 seconds.
When it appears that the outage will not be quickly
remedied, the ARTCC will usually request a nearby
aircraft, if there is one, to switch to the affected
frequency to broadcast communications instructions.
It is important, therefore, that the pilot wait at least
AIP - 7 MAR 13 - GEN 3.3-4 - Twenty-Second Edition Federal Aviation Administration
one minute before deciding that the ARTCC has
actually experienced a radio frequency failure. When
such an outage does occur, the pilot should, if
workload and equipment capability permit, maintain
a listening watch on the affected frequency while
attempting to comply with the recommended
communications procedures which follow.
4.2.3.1 If two-way communications cannot be
established with the ARTCC after changing frequencies,
a pilot should attempt to recontact the
transferring controller for the assignment of an
alternative frequency or other instructions.
4.2.3.2 When an ARTCC radio frequency failure
occurs after two-way communications have been
established, the pilot should attempt to reestablish
contact with the center on any other known ARTCC
frequency, preferably that of the next responsible
sector when practicable, and ask for instructions.
However, when the next normal frequency change
along the route is known to involve another ATC
facility, the pilot should contact that facility, if
feasible, for instructions. If communications cannot
be reestablished by either method, the pilot is
expected to request communications instructions
from the FSS appropriate to the route of flight.
NOTE-
The exchange of information between an aircraft and an
ARTCC through an FSS is quicker than relay via company
radio because the FSS has direct interphone lines to the
responsible ARTCC sector. Accordingly, when circumstances
dictate a choice between the two, during an
ARTCC frequency outage, relay via FSS radio is
recommended.
5. Radio Communications Failure
5.1 Pilots of IFR flights experiencing two-way radio
failure are expected to adhere to the procedures
prescribed in GEN 3.4, paragraph 12.
REFERENCE-
14 CFR Section 91.185
6. Position Reporting
6.1 The safety and effectiveness of traffic control
depends to a large extent on accurate position
reporting. In order to provide the proper separation
and expedite aircraft movements, ATC must be able
to make accurate estimates of the progress of every
aircraft operating on an IFR flight plan.
6.2 Position Identification
6.2.1 When a position report is to be made passing a
VOR radio facility, the time reported should be the
time at which the first complete reversal of the
“to/from” indicator is accomplished.
6.2.2 When a position report is made passing a
facility by means of an airborne automatic direction
finder (ADF), the time reported should be the time at
which the indicator makes a complete reversal.
6.2.3 When an aural or light-panel indication is used
to determine the time passing a reporting point, such
as a fan marker, Z marker, cone of silence or
intersection of range courses, the time should be
noted when the signal is first received and again when
it ceases. The mean of these two times should then be
taken as the actual time over the fix.
6.2.4 If a position is given with respect to distance
and direction from a reporting point, the distance and
direction should be computed as accurately as
possible.
6.2.5 Except for terminal transition purposes,
position reports or navigation with reference to aids
not established for use in the structure in which flight
is being conducted will not normally be required by
ATC.
6.3 Position Reporting Points
6.3.1 Federal Aviation Regulations require pilots to
maintain a listening watch on the appropriate
frequency and, unless operating under the provisions
of subparagraph 6.4, to furnish position reports
passing certain reporting points. Reporting points are
indicated by symbols on en route charts. The
designated compulsory reporting point symbol is the
solid triangle ; the “on request” reporting
point symbol is the open triangle . Reports
passing an “on request” reporting point are only
necessary when requested by ATC.
6.4 Position Reporting Requirements
6.4.1 Flights Along Airways or Routes. A position
report is required by all flights regardless of altitude,
including those operating in accordance with an ATC
clearance specifying “VFR-on-top,” over each
designated compulsory reporting point along the
route being flown.
6.4.2 Flight Along a Direct Route. Regardless of
the altitude or flight level being flown, including
flights operating in accordance with an ATC
clearance specifying “VFR-on-top,” pilots must
report over each reporting point used in the flight plan
to define the route of flight.
6.4.3 Flights in a Radar Environment. When
informed by ATC that their aircraft are in “RADAR
CONTACT,” PILOTS SHOULD DISCONTINUE
POSITION REPORTS OVER DESIGNATED REPORTING
POINTS. They should resume normal
position reporting when ATC advises “RADAR
CONTACT LOST” or “RADAR SERVICE TERMINATED.”
NOTE-
ATC will inform pilots that they are in “radar contact”
(a) When their aircraft is initially identified in the ATC
system; and (b) When radar identification is reestablished
after radar service has been terminated or radar contact
has been lost. Subsequent to being advised that the
controller has established radar contact, this fact will not
be repeated to the pilot when handed off to another
controller. At times, the aircraft identity will be confirmed
by the receiving controller; however, this should not be
construed to mean that radar contact has been lost. The
identity of transponder-equipped aircraft will be confirmed
by asking the pilot to “ident, squawk standby,” or
to change codes. Aircraft without transponders will be
advised of their position to confirm identity. In this case, the
pilot is expected to advise the controller if in disagreement
with the position given. If the pilot cannot confirm the
accuracy of the position given because of not being tuned
to the NAVAID referenced by the controller, the pilot should
ask for another radar position relative to the tuned in
NAVAID.
6.5 Position Report Items
6.5.1 Position reports should include the following
items:
6.5.1.1 Identification.
6.5.1.2 Position.
6.5.1.3 Time.
6.5.1.4 Altitude or flight level (Include actual
altitude or flight level when operating on a clearance
specifying “VFR-on-top.”).
6.5.1.5 Type of flight plan (not required in IFR
position reports made directly to ARTCCs or
approach control).
6.5.1.6 ETA and name of next reporting point.
6.5.1.7 The name only of the next succeeding
reporting point along the route of flight.
6.5.1.8 Pertinent remarks.
7. Additional Reports
7.1 The following reports should be made to ATC or
FSS facilities without a specific request:
7.1.1 At all times, report:
7.1.1.1 When vacating any previously assigned
altitude/flight level for a newly assigned altitude/
flight level.
7.1.1.2 When an altitude change will be made if
operating on a clearance specifying “VFR-on-top.”
7.1.1.3 When unable to climb/descend at a rate of at
least 500 feet per minute.
7.1.1.4 When approach has been missed. (Request
clearance for specific action; i.e., to alternative
airport, another approach, etc.).
7.1.1.5 Change in the average true airspeed (at
cruising altitude) when it varies by 5 percent or
10 knots (whichever is greater) from that filed in the
flight plan.
7.1.1.6 The time and altitude/flight level reaching a
holding fix or point to which cleared.
7.1.1.7 When leaving any assigned holding fix or
point.
NOTE-
The reports in subparagraphs 7.1.1.6 and 7.1.1.7 may be
omitted by pilots of aircraft involved in instrument training
at military area facilities when radar service is being
provided.
7.1.1.8 Any loss, in controlled airspace, of VOR,
TACAN, ADF, low frequency navigation receiver
capability, GPS anomalies while ...
from 2013 AIP - Aeronautical Information Publication