Chapter 7. International Operations
Section 1. Messages and Formats
a. Title 14 of the U.S. Code of Federal Regulations
(14 CFR) and the International Civil Aviation
Organization (ICAO) require flight plans for all civil
aircraft operation between the United States and
foreign locations. Bureau of Customs and Border
Protection requirements, international flight plan
information, and ADIZ penetration requirements are
listed in other publications; for example, the FAA
International Flight Information Manual (IFIM), the
Bureau of Customs and Border Protection Guide for
Private Flyers, the Aeronautical Information Manual
(AIM), Aeronautical Information Publication (AIP),
14 CFR Part 91, and 14 CFR Part 99. Landing Rights
Airports (LRA) and Airports of Entry (AOE) are
listed in the Airport/Facility Directory (A/FD)
b. This chapter provides guidance to FSS facilities
when transmitting international flight movement
messages. It incorporates relevant information from
ICAO and 14 CFR documents. All personnel
required to handle international messages must be
familiar with ICAO documents containing instructions for preparing and transmitting communications
through the Aeronautical Fixed Telecommunications
Network (AFTN) circuits. These documents should
be retained at facilities. FSS personnel must not act
as agents for any aircraft operating or dispatching
International telecommunications instructions are found
in International Standards and Recommended Practices,
ICAO Annex 10 – Aeronautical Telecommunications,
Volume II. PANS ATM DOC 4444, Procedures for Air
Navigation Services, lists various ATS movement
messages. Location indicators are contained in ICAO
Document 7910, and Designators for Aircraft Operating
Agencies, Aeronautical Authorities and Services are
contained in ICAO DOC 8585. FAA policies concerning
acceptance of messages for international transmission
are contained in 14 CFR Part 189.
c. Address the message to the proper FSS gateway
facility/sector for handling. FSSs that transmit only
occasional international messages or are unable to
determine the correct addressing for all air traffic
units concerned may refer or transfer the pilot to the
proper gateway facility/sector. The FSS gateway
facility/sector and their areas of responsibilities are as
1. Miami FSS Sector (MIA): Africa, Bermuda,
Canada, Caribbean, Central America, Europe, North
Atlantic, and South America.
2. Kenai FSS (ENA): Alaska.
3. Honolulu (HNL)/Oakland (OAK) Sectors:
4. Seattle Sector (SEA): Pacific Northwest to
d. To ensure that the FSS gateway facility/sector
understands your request, include T (transmit)
instructions in the first line of text.
OAK T ALL INTL ADDRESSEES
e. Use of FAA Form 72334 is mandatory for all
IFR flights that will depart U.S. domestic airspace
and enter international airspace. The filer is
responsible for providing the information required in
items 3 through 19.
7-1-2. AIR TRAFFIC SERVICE (ATS)
ATS messages, as used in this section, is a generic
term meaning and including: flight information,
alerting, air traffic advisory, and air traffic control
7-1-3. CATEGORIES OF MESSAGES
The following ATS messages, with their normal
priority indicators, are authorized for transmission by
any means; for example, AFTN, NADIN,
interphone, computertocomputer, or via the
aeronautical mobile service, as applicable.
a. Emergency Messages.
1. Distress messages and distress traffic,
including alerting (ALR) messages relating to
distress (DETRESFA) phaseSS.
2. Urgency messages, including alerting
messages relating to an alert (ALERFA) phase or to
an uncertainty (INCERFA) phaseSS.
3. Other messages concerning known or
suspected emergencies which do not fall under
subparas 7-1-3a1 and a2 and radio communications
failure (RCF) messagesFF or higher as required.
b. Movement and Control Messages.
1. Flight plan (FPL)FF.
2. Amendment and coordination messages.
(a) Departure (DEP)FF.
(b) Delay (DLA)GG.
(c) Arrival (ARR)GG.
(d) Boundary estimate (EST)FF.*
(e) Modification (CHG)FF.*
(f) Coordination (CDN)FF.*
(g) Acceptance (ACP)FF.*
3. Cancellation (CNL)GG.*
4. Clearances, flow control (SPL, CHG,
CDN)FF or DD.*
5. Transfer of control (TCX)FF.*
6. Requests (RQS)FF.*
7. Position reports (AIREP)FF.*
c. Flight Information Messages.
1. Traffic informationFF.*
2. Meteorological information (MET)FF or
3. Operation of aeronautical facilities and
essential airport information (NOTAM)GG.
* Normally exchanged between ATC units via voice
d. Technical Messages. Four categories of these
messages are specified for use on computertocomputer circuits only. They will not be sent on AFTN or
7-1-4. SERVICE MESSAGES
a. NADIN immediately generates a service
message to an originator when incorrect code or
routing indicators are detected.
SVC. ZKC121 QTA RPT
SVC. ZKC122 QTA MSR
b. Assign the appropriate priority indicator to
international service messages. When service
messages refer to messages previously transmitted,
assign the same priority prefix. Identify a service
message by inserting “SVC” as the first item of the
SVC. RUMES 231015
7-1-5. TRANSMISSION VIA NADIN
International messages are generally introduced on
NADIN for relay to AFTN circuits.
a. Operational Systems use the ICAO Flight Plan
or ServiceB message formats as described in the
Operational System operating procedures.
b. Handle international messages on NADIN for
relay to AFTN as follows:
1. Start of message. New Line Key.
2. Preamble (priority, space, addressee(s).
(a) Priority. Twocharacter precedence field.
(b) Addressee(s). Not to exceed 69 characters
or seven addressees, each addressee separated by a
(c) End of Line (EOL) new line key.
(d) End of Text (EOT) (enter function).
7-1-6. TRANSMISSION OF ATS
a. Air traffic service messages are interchanged in
the international air traffic control system in the
1. The preferred stepbystep mode wherein
each ACC/ARTCC sends forward the full current
(updated) flight plan information as the flight
2. The simultaneous mode wherein information
extracted from the filed flight plan (FPL) is sent
simultaneously to all ATS units along the route of
flight. In this mode, only amendments to the FPL,
plus necessary control information, are forwarded
from center to center as the flight progresses.
b. Prepare and transmit ATS messages as
described below. Address these messages as follows:
1. Include an eightcharacter addressee indicator for each addressee. When the number of addressees
required is more than the operational system
parameters allow, two or more transmissions of the
message must be made. The eightletter combination
addressee indicators are composed as follows:
(a) The fourletter ICAO location indicator;
for example, MPTO. Use only those listed in ICAO
DOC 7910 (Location Indicators). Some ICAO
eightcharacter addressees for Mexico and Canada
are listed in FAAO JO 7350.8, Location Identifiers.
(b) A fourletter designator for the facility
type/office, or if no designator has been assigned,
affix YXYX for military, ZZZX for aircraft in flight,
or YYYX for all other cases; for example,
MTPPYYYX. (See Note.)
ICAO DOC 8585, Designators for Aircraft Operating Agencies,
Aeronautical Authorities and Services.
The most frequently used and authorized designators are:
YAYX Government Civil Aviation Authority
(FAARegional Office or Headquarters).
YCYX Rescue Coordination Center (RCC).
YDYX Authority Supervising the Aerodrome.
YFYX Aeronautical Fixed Station FSS/IATSC).
YMYX Meteorological Office (NWS).
YNYX International NOTAM Office (NOF).
YTYX Telecommunications Authority.
YWYX Military Flight Operational Control Center
YXYX Military Organization (BASOPS).
YYYX Organization not allocated a twoletter designator.
ZOZX Oceanic Air Traffic Control Center.
ZPZX Air Traffic Service Reporting Office.
ZQZX Computer Facility at ACC/ARTCC.
ZRZX ACC/ARTCC. (Center in charge of a FIR/UIR when
the message is relevant to a VFR flight (AMIS)).
ZTZX Aerodrome Control Tower.
ZZZX Aircraft in flight.
(c) A oneletter designator will appear
following an air carrier designator to indicate the
department or division of the organization addressed.
2. Filing time. A sixdigit date/time group
indicating the time the message is filed with the FSS
c. Originator Indicator. Consists of an eightletter
sequence similar to an address indicator, identifying
the place of origin and the organization originating
d. Supplementary Address and Origin Information. When the fourletter designators YXYX,
ZZZX, or YYYX are used, identify the aircraft
operator or organization at the beginning of the text
preceding the startofATS data symbol ( ( ), in the
same order as in the addressee(s) and/or originator
indicator(s). Where there is more than one such
insertion, the last should be followed by the word
“stop.” Where there are one or more insertions in
respect to addressee indicators plus an insertion in
respect to the originator indicator, the word “from” is
to appear before that relating to the originator.
e. When addressing flight plan messages or
related amendments and flight plan cancellation
messages to centers, use one of the fourletter
designators as follows:
1. If message is relevant to IFR and:
(a) The ARTCC is computerequipped (U.S.
ARTCCs), use ZQZX.
(b) The center is not computerequipped, use
(c) Relevant to oceanic operations, use
Some centers may request specific addressing different
from above. ZTZX and ZPZX are used internationally, but
are not used in internal U.S. application.
2. If message is VFR (AMIS), use ZRZX.
3. If SVC or administrative, use ZRZX.
7-1-7. ORIGINATING MESSAGES
a. Messages for ATS purposes may be originated
with ATS units by aircraft in flight, or, through local
arrangements, a pilot, the operator, or their
b. Accept airfiled flight plans or changes in
destination information from aircraft inbound from
foreign locations and, if requested by the pilot, enter
Customs notification service.
c. Do not accept roundrobin flight plans to
international locations, other than Canada.
1. Only accept VFR roundrobin flight plans to Canada
if the filer of the flight plan is in possession of a valid
numbered letter of authorization and adheres to the
provisions contained therein.
2. Individual requests for the temporary authorization
letter should be directed to the appropriate service area
3. The temporary authorization letter mandates the pilot,
or responsible party, to provide the FSS with a name,
telephone number and authorization number for inclusion
in the remarks section of the flight plan.
4. FSS must log a double (2) count for the roundrobin
d. Do not accept assumed departure flight plans
when the destination is in a foreign country other than
e. Aircraft movement, control, and flight information messages for purposes other than ATS, such as
operational control, must be originated by the pilot,
the operator, or their designated representative.
7-1-8. ADDRESSING MESSAGES
a. Addressing the flight plan is determined by the
point of departure, the destination, and the FIR
boundaries to be penetrated during the course of the
b. Address IFR FPL messages to the ARTCC
serving the airport of departure and to all ATS units
(including oceanic) providing air traffic control
service or concerned with flight along part or the
whole of the route to be flown except FAA ATCTs
and other conterminous U.S. ARTCCs.
Within the North Atlantic (NAT) Region, FPLs on turbo jet
aircraft transiting the control areas of Gander Oceanic,
New York Oceanic, Reykjavik, Santa Maria Oceanic,
Shanwick Oceanic and Sondrestrom (south of 70 degrees)
within 90 nautical miles of the control area boundary,
must be addressed to the adjacent ACC to provide lateral
separation. For all other aircraft, a 120 nautical mile
proximity limit must apply.
c. Transmit all IFR FPLs to ARTCCs not less than
1 hour prior to the proposed departure time. Do not
hold FPLs until after departure time and transmit as
a combined FPL and departure message (DEP).
Separate FPL and DEP messages must be
ICAO flight plans do not require an acknowledgment to
the transmitting facility.
d. Address aircraft movement messages only to
those ATS units responsible for the provision of
relevant service, except when requested by the
operator concerned, these messages, when transmitted via the AFTN, may also be routed, as specified by
the operator or a representative to:
1. One addressee at the point of intended
landing or point of departure.
2. Not more than two operational control units
e. The ARTCC serving the departure airport must
transmit the DEP message on IFR aircraft to all
known recipients of the FPL message. Flights
between conterminous U.S. and Canada (excluding
Gander Oceanic), Alaska, Hawaii and Puerto Rico do
not require DEP messages. Discontinuance of DEP
messages affecting the route of flight can only be
accomplished by ICAO Regional Air Navigation
7-1-9. FLIGHT PLAN FORMS AND
a. All IFR flights that depart U.S. domestic
airspace and enter international airspace must use
FAA Form 72334, International Flight Plan (see
Appendix A), the ICAO Model Flight Plan Form in
ICAO DOC 4444, or an electronic equivalent. The
flight plan filer is responsible for providing the
information required in items 3 through 19.
1. The procedure described in paragraph a.
above also applies to IFR flight plans originating
within or transiting Pacific Flight Information
Regions (FIR) and flying to or from FIRs beyond the
Pacific Region including the North American (NAM)
The NAM Region encompasses the conterminous U.S.,
Alaska, and Canada to the North Pole.
2. VFR flights within the conterminous U.S.,
Canada, Mexico, Honolulu, Alaska, and San Juan
domestic control areas may use FAA Form 72331,
Flight Plan, or an electronic equivalent.
b. When paper forms are used, record on the form
the time the flight plan was filed. This time will
constitute evidence of the pilot's intention to comply
with Customs, Immigration, and Public Health
requirements and will be made available upon request
from these authorities
7-1-10. ICAO ATS MESSAGE FORMAT
The following are examples of ICAO message types
most likely to appear on AFTN/NADIN circuits. The
number above the data corresponds to the field type
numbers on the flight plan form (FAA Form 72334)
and on the chart of Standard ATS Messages and Their
Composition, Appendix A.
a. Departure Message (DEP). ARTCCs are the
designated ATS unit responsible for originating and
transmitting DEP messages on all IFR aircraft
departing airports within their center boundaries. IFR
flight plans must be transmitted to ARTCCs at least
1 hour before departure. This allows ARTCCs to
determine recipients of DEP message when domestic
portions are transmitted to ARTCCs in an automated
format. Do not hold FPLs and combine with DEP into
a single message.
b. Delay Message (DLA). Transmitted when
departure of an aircraft, for which an FPL message
has been transmitted, is postponed or delayed more
than 30 minutes after the estimated time of departure
contained in the FPL.
c. Alerting Message (ALR). Relating to an
overdue situation on an aircraft.
d. Supplementary Flight Plan (SPL). Information
must be sent to ATS units that transmit Request
Supplementary Flight Plan (RQS) messages.
e. Arrival Message (ARR). Sent only on Canadian
MOT, U.S. DOT, or FAA aircraft or upon request.
f. Current Flight Plan (CPL) Message. Originated
by and transmitted in a stepbystep mode between
successive ACCs and between the last ACC to the
control at the airport of intended landing. CPLs
contain only information relevant to that portion of
the route of flight which extends from the point of
entry into the next control area or FIR to the airport
of intended landing.
g. Acceptance (ACP) Message. Transmitted when
the data contained in a CPL message are found to be
acceptable to the receiving ACC.
h. Flight Plan Cancellation (CNL) Message.
Transmitted when a current (CPL) or filed flight plan
(FPL) message was transmitted and the flight is
7-1-11. FLIGHT PLAN CHANGES AND
a. Assume departure station duties when a flight
plan change is received from an aircraft en route to a
FAAO JO 7110.10, Para 648, Major Flight Plan Changes from En Route
FAAO JO 7110.10, Para 649, Change in ETA.
b. An FSS receiving a VFR flight plan
cancellation report from aircraft en route to a foreign
location must transmit a cancellation message to the
appropriate foreign tiein facility.
FAAO JO 7110.10, Para 6410, Flight Plan Closure.
7-1-12. AIR MOBILE SERVICE (AMS)
a. Air Mobile Service (AMS) is an international
air/ground communications network. It provides
service to en route aircraft primarily in support of
ATC and company operations, and collects meteorological data for dissemination. Although in the U.S.
this service is provided via contract (ARINC), FAA
flight service facilities may be required to relay
information on a casebycase basis.
b. The AMS network is composed of individual
units geographically limited to areas where effective
coordination and cooperation between ground
stations are possible.
c. For any individual route segment, the AMS
communication requirements will normally be met
by two or more network stations serving the flights on
that route segment. In general, these primary stations
serve the ACC serving the FIRs and the points of
takeoff and landing. In some cases, additional
suitably located stations are required to complete the
d. Each of these stations may be required at some
stage of the flight to exchange communications with
the aircraft, and when not so engaged, to intercept, as
required, communications exchanged between the
aircraft and any one of the other stations.
e. Stations providing regular network service to
aircraft operation along route segments in an ACC's
FIR are termed regular stations. Other network
stations will only be required to assist communications for that FIR in the event of communications
f. When communications permit, aircraft should
transmit their messages to the primary station of the
network from which they can most readily be
delivered to their ultimate destination. In particular,
aircraft reports required by ATC should be
transmitted to the network station serving the ATC
center in whose area the aircraft is flying. Conversely,
messages to aircraft in flight should be transmitted
direct to the aircraft by the network station serving the
location of the originator.
g. Messages passed from aircraft to a network
station should be intercepted and acknowledged by
other stations which serve locations where the
information is also required. Such intercepts provide
instantaneous delivery of information and eliminates
the transmission of messages over the AFTN.
Networks may not be used for transmission of aircraft
reports except under the intercept principle.
Acknowledgments of intercept must be made
immediately after the acknowledgment of receipt by
the station to which the message was passed. In the
absence of acknowledgment of intercept within
1 minute, the station accepting the message from the
aircraft must forward the message via the AFTN to
the ultimate destination.
h. In areas or on routes where radio operations,
lengths of flights, or distance between stations
require additional measures to ensure continuity of
communications throughout the route segment, the
stations must share the responsibility of primary
guard whereby each station will provide the primary
guard for that portion of the flight during which the
messages from the aircraft can be handled most
effectively by that station.
i. During its tenure of primary guard, each station
1. Be responsible for designating primary and
secondary frequencies for communications with
2. Receive all position reports and handle other
messages from and to the aircraft essential to the safe
conduct of the flight.
3. Be responsible for the action required in case
of failure of communication.
j. Transfer of primary guard from one primary
station to the next will normally take place at the time
of traversing FIR or control area boundaries. When
communications conditions so demand, a station
may be required to retain primary guard beyond
geographical boundaries or release its guard before
the aircraft reaches a boundary.
7-1-13. AIREPs (POSITION REPORTS)
a. AIREPs are messages from an aircraft to a
ground station. AIREPs are normally comprised of
the aircraft's position, time, flight level, ETA over its
next reporting point, destination ETA, fuel
remaining, and meteorological information. When
recording an AIREP on data terminals or written
copy, the following procedures must be used.
1. Each line must begin at the left margin.
2. A new line must be used for each
3. If communications allow, each report must
contain the following items in the order shown:
(a) Message type aerodrome reference point
(b) Call sign of the calling station (aircraft).
(c) Text of the message.
(d) Call sign of the station called or receiving
station followed by the appropriate abbreviation to
indicate received, readback, or no reply heard.
(e) Call sign of station(s) acknowledging
intercept followed by appropriate abbreviation to
(f) Designation of frequency used.
*2866QM 8903VO 13300YH
2932QI *5631TY 11384XM
2998QL 6532UA 13294YF
5628TO 10048WH 17904ZC
*For Alaskan domestic use only.
(g) Time in UTC of the communication.
4. Missing parts of the message text must be
indicated by the letter “M.”
ARP CPC583 KBRO 2100 F330 MMTM 2128
ETA XMMMX 2248 FUEL 0324
b. AIREPs may be filed from any aircraft inflight
within World Meteorological Organization (WMO)
areas of responsibility in conformity with ICAO
requirements for position, operational, or meteorological reporting in AIREP format. AIREP information
must be disseminated to ATC, company, and
meteorological offices as required. AIREPs consist
of three sections comprised of 12 items. AIREPs may
be filed in one, two, or three sections as follows:
1. Section 1, Routine report. A position report
(PSNRP) comprising the Message Type Designator
ARP and the following items:
(a) Item 1, Aircraft identification.
(b) Item 2, Position. Record position in
latitude (degrees as two numerics, or degrees and
minutes as four numerics, followed without a space
by N or S) and longitude (degrees as three numerics,
or degrees and minutes as five numerics, followed
without a space by E or W) or as a significant point
identified by a coded designator (twotofive
characters) or as a significant point followed by a
magnetic bearing (three numerics) and a distance in
nautical miles (three numerics) from the point, such
as 4620N07805W, 4620N078W, 46N078W, LN,
MAY or DUB180040. Precede significant point by
ABM (abeam), if applicable.
(c) Item 3, Time. Record time in hours and
minutes UTC (four numerics). The time recorded
must be the actual time of the aircraft at the position
and not the time of origination or transmission of the
(d) Item 4, Flight level or altitude. Record
flight level as “F” followed by three numerics when
on standard pressure altimeter setting, such as F370.
Record altitude in meters followed by M, or in feet
followed by FT, when on QNH. Record ASC (level)
when climbing, or DES (level) when descending to
a new level after passing the significant point.
(e) Item 5, Next position and time over.
Record the next reporting point and the estimated
time over such reporting point, or record the
estimated position that will be reached 1 hour later,
according to the position reporting procedures in
effect. Use the data conventions specified in subpara
7113b1(b), Item 2, Position, for position. Record
time in minutes past the hour (two numerics) or in
hours and minutes UTC (four numerics) when
PSNRP portion of AIREP prepared by De Ridder and
addressed to Canadian Pacific Airlines (CPC) in Toronto
and Mexico City:
FF CYYZCPCX MMMXXMZT
ARP CPC583 KBRO 2100 F370 MMTM28
2. Section 2. When reported by the pilot:
(a) Item 6, Estimated Time of Arrival (ETA).
Record ETA by the fourletter location indicator of
the airport of first intended landing, or if no location
indicator exists, the name of the airport followed by
the estimated time of arrival at this aerodrome in
hours and minutes UTC (four numerics).
(b) Item 7, Endurance. Record fuel in hours
and minutes (four numerics).
3. Section 3. A full AIREP comprising a
PSNRP, company information, and en route
(a) Item 8, Air temperature. Record PS (plus)
or MS (minus), no space, followed by the
temperature in degrees centigrade corrected for
instrument error and airspeed, such as MS05.
(b) Item 9, Spot wind or mean wind and
position. Spot wind is used whenever practical and
normally refers to the position given in subpara
7113b1(b), Item 2, Position. When a spot wind is
given for any other location, record its position.
Whenever it is not practical to record spot wind,
record the mean wind between two fixes, followed by
the word "mean," and the position of the midpoint
between the two fixes. Record wind direction in
degrees true (three numerics) and wind speed in knots
(two or three numerics), separated by an oblique
stroke, such as 345/55. Record the direction of
variable winds of a given strength as VRB, such as
VRB/10. Record light and variable winds or calm as
LV. If wind position is required, record latitude and
longitude to the nearest whole degree, using the data
convention specified in Item 2, such as 22N180W.
AIREP comprised of PSNRP and aircraft operator
FF CYYZCPCX MMMXXMZT
ARP CPC583 KBRO 2100 F370 MMTM28
MMMX 2248 FUEL 0324
(c) Item 10, Turbulence (TURB). Record
severe turbulence as TURB SEV and moderate
turbulence as TURB MOD. If turbulence is
experienced in cloud, add INC (in cloud). If in
subsonic flight, report severe turbulence as soon as
possible after occurrence. This requires AIREP
SPECIAL. Record and report moderate turbulence
only if encountered within last 10 minutes prior to
reaching position in subpara 7113b1(b), Item 2,
Position. If in transonic or supersonic flight, report
severe or moderate turbulence as soon as possible
after occurrence. This requires AIREP SPECIAL.
(d) Item 11, Icing. Record severe icing as ICE
SEV, moderate icing as ICE MOD. Report severe
icing as soon as possible after occurrence. This
requires AIREP SPECIAL. Record and report
moderate icing only if encountered within last
10 minutes prior to reaching position in subpara
7113b1(b), Item 2, Position.
(e) Item 12, Supplementary Information.
Record data which in the opinion of the pilotincommand are of aeronautical interest.
(1) Present Weather. Rain (RA), Snow
(SN), Freezing rain (FZRA), Funnel cloud (FC)
Waterspout or tornado (+FC), Thunderstorm (TS) on
or near flight path, Front (FRONT).
(2) Clouds. If heights of cloud bases and/or
tops can be accurately ascertained, amount of clouds
scattered (SCT) if clear intervals predominate,
broken (BKN) if cloud masses predominate, or
continuous (CNS) type of clouds only if cumulonimbus (CB), and an indication of the bases (BASE)
and/or the tops (TOP) together with the respective
height indication F (number) or (number) or
(number) M/ or (number) FT.
(3) Turbulence and Icing. Moderate turbulence (TURB MOD) if in subsonic flight, or moderate
aircraft icing (ICE MOD) observed prior to the last
(4) DValue. Reading or radio altimeter
minus reading of pressure altimeter set to 1013.2 mb
and corrected for calibration and position error;
record differences as PS (plus) or MS (minus), no
space, followed by the number of meters or feet.
FF CYYZCPCX MMMXXMZT KMIAYMYX
ARP CPC583 2709N05415W 2212 F330
23N056W 59 0035 FUEL 0324 M534 310/60
MEAN 2543N05532W TURB MOD ICE MOD SCT
CB TOP F280
Transmit to the WMO office serving the FIR where the
report is made.
(5) Operationally Significant Weather
Radar Echoes (echo or echo line). True bearing of
center of echo or line and distance from aircraft in
nautical miles; if appropriate, indicate weather
intensifying or weakening and whether no gaps, some
gaps, or frequent gaps are observed.
(6) Significant differences between conditions encountered and those forecast for the flight,
such as forecast thunderstorms not observed or
freezing rain not forecast.
(7) If the position of the phenomenon
reported is not the same as the position given under
subpara 7113b1(b), Item 2, Position, report it after
7-1-14. AIREP SPECIALS (ARS)
a. Turbulence. TURB SEV encountered while in
subsonic flight is reported as soon as possible after
occurrence and requires AIREP SPECIAL. TURB
MOD is reported only if encountered within
10 minutes prior to reaching reporting position. If in
transonic or supersonic flight, TURB MOD and SEV
is reported as soon as possible and requires AIREP
b. Icing. ICE SEV is reported as soon as possible
after occurrence and requires AIREP SPECIAL. ICE
MOD is reported only if encountered within last
10 minutes prior to reaching reporting position.
ARS PAA101 5045N02015W 1536 F310 ASC
F350 51N030W 21 FUEL 0900 ICE SEV
7-1-15. ARTCC RELAY OF VFR
ARTCC operators must relay all international VFR
flight movement messages to the adjacent FSS unless
that facility is also an addressee.
If an overseas unit erroneously routes a VFR movement
message to an ARTCC, the automatic NADIN switch will
not divert it to an FSS.