JEPPESEN GENERAL AIRWAY MANUAL (Issue Date 1 JUL 21)

(b) Data link applications processor with TIS software installed.

(d) Optional equipment includes a digital heading source to correct display errors

caused by “crab angle” and turning maneuvers.
NOTE: Some of the above functions will likely be combined into single pieces of
avionics, such as (a) and (b).

3. To be visible to the TIS client, the intruder aircraft must, at a minimum, have an operat-

ing transponder (Mode A, C or S). All altitude information provided by TIS from intruder
aircraft is derived from Mode C reports, if appropriately equipped.

4. TIS will initially be provided by the terminal Mode S systems that are paired with ASR-9

digital primary radars. These systems are in locations with the greatest traffic densities,
thus will provide the greatest initial benefit. The remaining terminal Mode S sensors,
which are paired with ASR-7 or ASR-8 analog primary radars, will provide TIS pending
modification or relocation of these sites. See FIG 4-5-5, Terminal Mode S Radar Sites,
for site locations. There is no mechanism in place, such as NOTAMs, to provide status
update on individual radar sites since TIS is a nonessential, supplemental information
service.
The FAA also operates en route Mode S radars (not illustrated) that rotate once every
12 seconds. These sites will require additional development of TIS before any possible
implementation. There are no plans to implement TIS in the en route Mode S radars at
the present time.

Capabilities.

1. TIS provides ground-based surveillance information over the Mode S data link to prop-

erly equipped client aircraft to aid in visual acquisition of proximate air traffic. The actual
avionics capability of each installation will vary and the supplemental handbook material
must be consulted prior to using TIS. A maximum of eight (8) intruder aircraft may be
displayed; if more than eight aircraft match intruder parameters, the eight “most signifi-
cant” intruders are uplinked. These “most significant” intruders are usually the ones in
closest proximity and/or the greatest threat to the TIS client.

2. TIS, through the Mode S ground sensor, provides the following data on each intruder

aircraft:

(a) Relative bearing information in 6-degree increments.
(b) Relative range information in 1/8 NM to 1 NM increments (depending on range).

(from 1,000-3,500 feet) if the intruder aircraft has operating altitude reporting capa-
bility.

(d) Estimated intruder ground track in 45-degree increments.

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SECTION 5. SURVEILLANCE SYSTEMS

(e) Altitude trend data (level within 500 fpm or climbing/descending >500 fpm) if the

intruder aircraft has operating altitude reporting capability.

(f) Intruder priority as either an “traffic advisory” or “proximate” intruder.

3. When flying from surveillance coverage of one Mode S sensor to another, the transfer

of TIS is an automatic function of the avionics system and requires no action from the
pilot.

4. There are a variety of status messages that are provided by either the airborne system

or ground equipment to alert the pilot of high priority intruders and data link system
status. These messages include the following:

(a)

Alert. Identifies a potential collision hazard within 34 seconds. This alert may be
visual and/or audible, such as a flashing display symbol or a headset tone. A target
is a threat if the time to the closest approach in vertical and horizontal coordinates
is less than 30 seconds and the closest approach is expected to be within 500 feet
vertically and 0.5 nautical miles laterally.

(b)

TIS Traffic. TIS traffic data is displayed.

(c)

Coasting. The TIS display is more than 6 seconds old. This indicates a missing
uplink from the ground system. When the TIS display information is more than 12
seconds old, the “No Traffic” status will be indicated.

(d)

No Traffic. No intruders meet proximate or alert criteria. This condition may exist
when the TIS system is fully functional or may indicate “coasting” between 12 and
59 seconds old (see (c) above).

(e)

TIS Unavailable. The pilot has requested TIS, but no ground system is available.
This condition will also be displayed when TIS uplinks are missing for 60 seconds
or more.

(f)

TIS Disabled. The pilot has not requested TIS or has disconnected from TIS.

(g)

Good-bye. The client aircraft has flown outside of TIS coverage.
NOTE: Depending on the avionics manufacturer implementation, it is possible that
some of these messages will not be directly available to the pilot.

5. Depending on avionics system design, TIS may be presented to the pilot in a variety of

different displays, including text and/or graphics. Voice annunciation may also be used,
either alone or in combination with a visual display. FIG 4-5-6, Traffic Information Serv-
ice (TIS), Avionics Block Diagram, shows an example of a TIS display using symbology
similar to the Traffic Alert and Collision Avoidance System (TCAS) installed on most
passenger air carrier/commuter aircraft in the U.S. The small symbol in the center rep-
resents the client aircraft and the display is oriented “track up,” with the 12 o'clock posi-
tion at the top. The range rings indicate 2 and 5 NM. Each intruder is depicted by a
symbol positioned at the approximate relative bearing and range from the client aircraft.
The circular symbol near the center indicates an “alert” intruder and the diamond sym-
bols indicate “proximate” intruders.

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SECTION 5. SURVEILLANCE SYSTEMS

6. The inset in the lower right corner of FIG 4-5-6, Traffic Information Service (TIS), Avion-

ics Block Diagram, shows a possible TIS data block display. The following information is
contained in this data block:

(a) The intruder, located approximately four o'clock, three miles, is a “proximate” air-

craft and currently not a collision threat to the client aircraft. This is indicated by the
diamond symbol used in this example.

(b) The intruder ground track diverges to the right of the client aircraft, indicated by the

small arrow.

the “-07” located under the symbol.

(d) The intruder is descending >500 fpm, indicated by the downward arrow next to the

“-07” relative altitude information. The absence of this arrow when an altitude tag is
present indicates level flight or a climb/descent rate less than 500 fpm.
NOTE: If the intruder did not have an operating altitude encoder (Mode C), the alti-
tude and altitude trend “tags” would have been omitted.

Limitations.

1. TIS is

NOT intended to be used as a collision avoidance system and does not relieve

the pilot’s responsibility to “see and avoid” other aircraft (see Paragraph 5-5-8, See and
Avoid). TIS must not be used for avoidance maneuvers during IMC or other times when
there is no visual contact with the intruder aircraft. TIS is intended only to assist in visual
acquisition of other aircraft in VMC. Avoidance maneuvers are neither provided nor
authorized as a direct result of a TIS intruder display or TIS alert.

2. While TIS is a useful aid to visual traffic avoidance, it has some system limitations that

must be fully understood to ensure proper use. Many of these limitations are inherent in
secondary radar surveillance. In other words, the information provided by TIS will be no
better than that provided to ATC. Other limitations and anomalies are associated with
the TIS predictive algorithm.

(a)

Intruder Display Limitations. TIS will only display aircraft with operating trans-
ponders installed. TIS relies on surveillance of the Mode S radar, which is a “sec-
ondary surveillance” radar similar to the ATCRBS described in paragraph 4-5-2.

(b)

TIS Client Altitude Reporting Requirement. Altitude reporting is required by the
TIS client aircraft in order to receive TIS. If the altitude encoder is inoperative or
disabled, TIS will be unavailable, as TIS requests will not be honored by the
ground system. As such, TIS requires altitude reporting to determine the Proximity
Coverage Volume as indicated in FIG 4-5-4. TIS users must be alert to altitude
encoder malfunctions, as TIS has no mechanism to determine if client altitude
reporting is correct. A failure of this nature will cause erroneous and possibly
unpredictable TIS operation. If this malfunction is suspected, confirmation of alti-
tude reporting with ATC is suggested.

RADIO DATA - GENERAL

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SECTION 5. SURVEILLANCE SYSTEMS

(c)

Intruder Altitude Reporting. Intruders without altitude reporting capability will be
displayed without the accompanying altitude tag. Additionally, nonaltitude reporting
intruders are assumed to be at the same altitude as the TIS client for alert compu-
tations. This helps to ensure that the pilot will be alerted to all traffic under radar
coverage, but the actual altitude difference may be substantial. Therefore, visual
acquisition may be difficult in this instance.

(d)

Coverage Limitations. Since TIS is provided by ground-based, secondary surveil-
lance radar, it is subject to all limitations of that radar.

If an aircraft is not detec-

ted by the radar, it cannot be displayed on TIS. Examples of these limitations
are as follows:

(1) TIS will typically be provided within 55 NM of the radars depicted in FIG 4-5-5,

Terminal Mode S Radar Sites. This maximum range can vary by radar site
and is always subject to “line of sight” limitations; the radar and data link sig-
nals will be blocked by obstructions, terrain, and curvature of the earth.

(2) TIS will be unavailable at low altitudes in many areas of the country, particu-

larly in mountainous regions. Also, when flying near the “floor” of radar cover-
age in a particular area, intruders below the client aircraft may not be detec-
ted by TIS.

(3) TIS will be temporarily disrupted when flying directly over the radar site pro-

viding coverage if no adjacent site assumes the service. A ground-based
radar, similar to a VOR or NDB, has a zenith cone, sometimes referred to as
the cone of confusion or cone of silence. This is the area of ambiguity directly
above the station where bearing information is unreliable. The zenith cone
setting for TIS is 34 degrees: Any aircraft above that angle with respect to the
radar horizon will lose TIS coverage from that radar until it is below this
34 degree angle. The aircraft may not actually lose service in areas of multi-
ple radar coverage since an adjacent radar will provide TIS. If no other TIS-
capable radar is available, the “Good-bye” message will be received and TIS
terminated until coverage is resumed.

(e)

Intermittent Operations. TIS operation may be intermittent during turns or other
maneuvering, particularly if the transponder system does not include antenna
diversity (antenna mounted on the top and bottom of the aircraft). As in (d) above,
TIS is dependent on two-way, “line of sight” communications between the aircraft
and the Mode S radar. Whenever the structure of the client aircraft comes between
the transponder antenna (usually located on the underside of the aircraft) and the
ground-based radar antenna, the signal may be temporarily interrupted.

(f)

TIS Predictive Algorithm. TIS information is collected one radar scan prior to the
scan during which the uplink occurs. Therefore, the surveillance information is
approximately 5 seconds old. In order to present the intruders in a “real time” posi-
tion, TIS uses a “predictive algorithm” in its tracking software. This algorithm uses
track history data to extrapolate intruders to their expected positions consistent

RADIO DATA - GENERAL

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SECTION 5. SURVEILLANCE SYSTEMS

with the time of display in the cockpit. Occasionally, aircraft maneuvering will
cause this algorithm to induce errors in the TIS display. These errors primarily
affect relative bearing information; intruder distance and altitude will remain rela-
tively accurate and may be used to assist in “see and avoid.” Some of the more
common examples of these errors are as follows:

(1) When client or intruder aircraft maneuver excessively or abruptly, the tracking

algorithm will report incorrect horizontal position until the maneuvering aircraft
stabilizes.

(2) When a rapidly closing intruder is on a course that crosses the client at a

shallow angle (either overtaking or head on) and either aircraft abruptly
changes course within

NM, TIS will display the intruder on the opposite

side of the client than it actually is.
These are relatively rare occurrences and will be corrected in a few radar
scans once the course has stabilized.

(g)

Heading/Course Reference. Not all TIS aircraft installations will have onboard
heading reference information. In these installations, aircraft course reference to
the TIS display is provided by the Mode S radar. The radar only determines ground
track information and has no indication of the client aircraft heading. In these
installations, all intruder bearing information is referenced to ground track and does
not account for wind correction. Additionally, since ground-based radar will require
several scans to determine aircraft course following a course change, a lag in TIS
display orientation (intruder aircraft bearing) will occur. As in (f) above, intruder dis-
tance and altitude are still usable.

(h)

Closely-Spaced Intruder Errors. When operating more than 30 NM from the
Mode S sensor, TIS forces any intruder within 3/8 NM of the TIS client to appear at
the same horizontal position as the client aircraft. Without this feature, TIS could
display intruders in a manner confusing to the pilot in critical situations (for exam-
ple, a closely-spaced intruder that is actually to the right of the client may appear
on the TIS display to the left). At longer distances from the radar, TIS cannot accu-
rately determine relative bearing/distance information on intruder aircraft that are in
close proximity to the client.
Because TIS uses a ground-based, rotating radar for surveillance information, the
accuracy of TIS data is dependent on the distance from the sensor (radar) provid-
ing the service. This is much the same phenomenon as experienced with ground-
based navigational aids, such as a VOR. As distance from the radar increases, the
accuracy of surveillance decreases. Since TIS does not inform the pilot of distance
from the Mode S radar, the pilot must assume that any intruder appearing at the
same position as the client aircraft may actually be up to 3/8 NM away in any direc-
tion. Consistent with the operation of TIS, an alert on the display (regardless of dis-
tance from the radar) should stimulate an outside visual scan, intruder acquisition,
and traffic avoidance based on outside reference.

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SECTION 5. SURVEILLANCE SYSTEMS

Reports of TIS Malfunctions.

1. Users of TIS can render valuable assistance in the early correction of malfunctions by

reporting their observations of undesirable performance. Reporters should identify the
time of observation, location, type and identity of aircraft, and describe the condition
observed; the type of transponder processor, and software in use can also be useful
information. Since TIS performance is monitored by maintenance personnel rather than
ATC, it is suggested that malfunctions be reported by radio or telephone to the nearest
Flight Service Station (FSS) facility.

NOTE: TIS operates at only those terminal Mode S radar sites depicted in FIG 4-5-5. Though
similar in some ways, TIS is not related to TIS-B (Traffic Information Service — Broadcast).

AUTOMATIC DEPENDENT SURVEILLANCE-BROADCAST

(ADS-B) SERVICES

Introduction.

1. Automatic Dependent Surveillance-Broadcast (ADS-B) is a surveillance technology

deployed throughout the NAS (see FIG 4-5-7). The ADS-B system is composed of air-
craft avionics and a ground infrastructure. Onboard avionics determine the position of
the aircraft by using the GNSS and transmit its position along with additional information
about the aircraft to ground stations for use by ATC and other ADS-B services. This
information is transmitted at a rate of approximately once per second. (See FIG 4-5-8
and FIG 4-5-9.)

4-5-7

RADIO DATA - GENERAL

422

SECTION 5. SURVEILLANCE SYSTEMS

not require it, operators equipped with ADS-B In will realize additional benefits from
ADS-B broadcast services: Traffic Information Service-Broadcast (TIS-B) (Paragraph
4-5-8) and Flight Information Service-Broadcast (FIS-B) (Paragraph 4-5-9).

ADS-B Certification and Performance Requirements.
ADS-B equipment may be certified as a surveillance source for air traffic separation services
using ADS-B Out. ADS-B equipment may also be certified for use with ADS-B In advisory
services that enable appropriately equipped aircraft to display traffic and flight information.
Refer to the aircraft’s flight manual supplement or Pilot Operating Handbook for the capabili-
ties of a specific aircraft installation.

ADS-B Capabilities and Procedures.

1. ADS-B enables improved surveillance services, both air-to-air and air-to-ground, espe-

cially in areas where radar is ineffective due to terrain or where it is impractical or cost
prohibitive. Initial NAS applications of air-to-air ADS-B are for “advisory” use only,
enhancing a pilot’s visual acquisition of other nearby equipped aircraft either when air-
borne or on the airport surface. Additionally, ADS-B will enable ATC and fleet operators
to monitor aircraft throughout the available ground station coverage area.

FIGURE 4-5-8

En Route — ADS-B/ADS-R/TIS-B/FIS-B Service Ceilings/Floors

RADIO DATA - GENERAL

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SECTION 5. SURVEILLANCE SYSTEMS

FIGURE 4-5-9

Terminal — ADS-B/ADS-R/TIS-B/FIS-B Service Ceilings/Floors

2. One of the data elements transmitted by ADS-B is the aircraft’s Flight Identification (FLT

ID). The FLT ID is comprised of a maximum of seven alphanumeric characters and
must correspond to the aircraft identification filed in the flight plan. For airline and com-
muter aircraft, the FLT ID is usually the company name and flight number (for example,
AAL3432), and is typically entered into the avionics by the flight crew during preflight.
For general aviation (GA), if aircraft avionics allow dynamic modification of the FLT ID,
the pilot can enter it prior to flight. However, some ADS-B avionics require the FLT ID to
be set to the aircraft registration number (for example, N1234Q) by the installer and
cannot be changed by the pilot from the cockpit. In both cases, the FLT ID must corre-
spond to the aircraft identification filed in its flight plan.
ATC automation systems use the transmitted ADS-B FLT ID to uniquely identify each
aircraft within a given airspace, and to correlate it to its filed flight plan for the purpose of
providing surveillance and separation services. If the FLT ID and the filed aircraft identi-
fication are not identical, a Call Sign Mis-Match (CSMM) is generated and ATC automa-
tion systems may not associate the aircraft with its filed flight plan. In this case, air traffic
services may be delayed or unavailable until the CSMM is corrected. Consequently, it is
imperative that flight crews and GA pilots ensure the FLT ID entry correctly matches the
aircraft identification filed in their flight plan.

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SECTION 5. SURVEILLANCE SYSTEMS

3. Each ADS-B aircraft is assigned a unique ICAO address (also known as a 24-bit

address) that is broadcast by the ADS-B transmitter. This ICAO address is programmed
at installation. Should multiple aircraft broadcast the same ICAO address while transit-
ing the same ADS-B Only Service Volume, the ADS-B network may be unable to track
the targets correctly. If radar reinforcement is available, tracking will continue. If radar is
unavailable, the controller may lose target tracking entirely on one or both targets. Con-
sequently, it is imperative that the ICAO address entry is correct.

4. Aircraft that are equipped with ADS-B avionics on the UAT datalink have a feature that

allows them to broadcast an anonymous 24-bit ICAO address. In this mode, the UAT
system creates a randomized address that does not match the actual ICAO address
assigned to the aircraft. The UAT anonymous 24-bit address feature may only be used
when the operator has not filed an IFR flight plan and is not requesting ATC services. In
the anonymity mode, the aircraft’s beacon code must be set to 1200 and, depending on
the manufacturer’s implementation, the aircraft FLT ID might not be transmitted. Pilots
should be aware that while in UAT anonymity mode, they will not be eligible to receive
ATC separation and flight following services, and may not benefit from enhanced ADS-
B search and rescue capabilities.

5. ADS-B systems integrated with the transponder will automatically set the applicable

emergency status when 7500, 7600, or 7700 are entered into the transponder. ADS-B
systems not integrated with the transponder, or systems with optional emergency
codes, will require that the appropriate emergency code is entered through a pilot inter-
face. ADS-B is intended for inflight and airport surface use. Unless otherwise directed
by ATC, transponder/ADS-B systems should be turned “on” and remain “on” whenever
operating in the air or on the airport surface movement area.

ATC Surveillance Services using ADS-B — Procedures and Recommended Phraseol-
ogy
Radar procedures, with the exceptions found in this paragraph, are identical to those proce-
dures prescribed for radar in AIM Chapter 4 and Chapter 5.

1. Preflight:

If ATC services are anticipated when either a VFR or IFR flight plan is filed, the aircraft
identification (as entered in the flight plan) must be entered as the FLT ID in the ADS-B
avionics.

2. Inflight:

When requesting surveillance services while airborne, pilots must disable the anony-
mous feature, if so equipped, prior to contacting ATC. Pilots must also ensure that their
transmitted ADS-B FLT ID matches the aircraft identification as entered in their flight
plan.

3. Aircraft with an Inoperative/Malfunctioning ADS-B Transmitter:

(a) ATC will inform the flight crew when the aircraft's ADS-B transmitter appears to be

inoperative or malfunctioning:

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SECTION 5. SURVEILLANCE SYSTEMS

PHRASEOLOGY:
YOUR ADS-B TRANSMITTER APPEARS TO BE INOPERATIVE/MALFUNC-
TIONING. STOP ADS-B TRANSMISSIONS.

(b) ATC will inform the flight crew if it becomes necessary to turn off the aircraft's

ADS-B transmitter.
PHRASEOLOGY:
STOP ADS-B TRANSMISSIONS.

Loss of automatic altitude reporting capabilities (encoder failure) will result in loss
of ATC altitude advisory services.

4. Procedures for Accommodation of Non-ADS-B Equipped Aircraft:

(a) Pilots of aircraft not equipped with ADS-B may only operate outside airspace des-

ignated as ADS-B airspace in 14 CFR §91.225. Pilots of unequipped aircraft wish-
ing to fly any portion of a flight in ADS-B airspace may seek a deviation from the
regulation to conduct operations without the required equipment. Direction for
obtaining this deviation are available in Advisory Circular 90-114.

(b) While air traffic controllers can identify which aircraft are ADS-B equipped and

which are not, there is no indication if a non-equipped pilot has obtained a preflight
authorization to enter ADS-B airspace. Situations may occur when the pilot of a
non-equipped aircraft, without an authorization to operate in ADS-B airspace
receives an ATC-initiated in-flight clearance to fly a heading, route, or altitude that
would penetrate ADS-B airspace. Such clearances may be for traffic, weather, or
simply to shorten the aircraft’s route of flight. When this occurs, the pilot should
acknowledge and execute the clearance, but must advise the controller that they
are not ADS-B equipped and have not received prior authorization to operate in
ADS-B airspace. The controller, at their discretion, will either acknowledge and
proceed with the new clearance, or modify the clearance to avoid ADS-B airspace.
In either case, the FAA will normally not take enforcement action for non-equipage
in these circumstances.

NOTE: Pilots operating without ADS-B equipment must not request route or altitude
changes that will result in an incursion into ADS-B airspace except for safety of flight;
for example, weather avoidance. Unequipped aircraft that have not received a pre-flight
deviation authorization will only be considered in compliance with regulation if the
amendment to flight is initiated by ATC.
EXAMPLE 1: ATC: “November Two Three Quebec, turn fifteen degrees left, proceed
direct Bradford when able, rest of route unchanged.”
Aircraft: “November Two Three Quebec, turning fifteen degrees left, direct Bradford
when able, rest of route unchanged. Be advised, we are negative ADS-B equipment
and have not received authorization to operate in ADS-B airspace.”

RADIO DATA - GENERAL

427

SECTION 5. SURVEILLANCE SYSTEMS

ATC: “November Two Three Quebec, roger”
or
“November Two Three Quebec, roger, turn twenty degrees right, rejoin Victor Ten, rest
of route unchanged.”
EXAMPLE 2: ATC: “November Four Alpha Tango, climb and maintain one zero thou-
sand for traffic.”
Aircraft: “November Four Alpha Tango, leaving eight thousand for one zero thousand.
Be advised, we are negative ADS-B equipment and have not received authorization to
operate in ADS-B airspace.”
ATC: “November Four Alpha Tango, roger”
or
“November Four Alpha Tango, roger, cancel climb clearance, maintain eight thousand.”
REFERENCE—Federal Register Notice, Volume 84, Number 62, dated April 1, 2019.

ADS-B Limitations.
The ADS-B cockpit display of traffic is NOT intended to be used as a collision avoidance
system and does not relieve the pilot’s responsibility to “see and avoid” other aircraft. (See
Paragraph 5-5-8, See and Avoid). ADS-B must not be used for avoidance maneuvers during
IMC or other times when there is no visual contact with the intruder aircraft. ADS-B is inten-
ded only to assist in visual acquisition of other aircraft. No avoidance maneuvers are provi-
ded or authorized, as a direct result of an ADS-B target being displayed in the cockpit.

Reports of ADS-B Malfunctions.
Users of ADS-B can provide valuable assistance in the correction of malfunctions by report-
ing instances of undesirable system performance. Since ADS-B performance is monitored by
maintenance personnel rather than ATC, report malfunctions to the nearest Flight Service
Station (FSS) facility by radio or telephone, or by sending an email to the ADS-B help desk
at adsb@faa.gov. Reports should include:

1. Condition observed;
2. Date and time of observation;
3. Altitude and location of observation;
4. Type and call sign of the aircraft; and
5. Type and software version of avionics system.

TRAFFIC INFORMATION SERVICE-BROADCAST (TIS-B)

Introduction.
TIS-B is the broadcast of ATC derived traffic information to ADS-B equipped (1090ES or
UAT) aircraft from ground radio stations. The source of this traffic information is derived from

4-5-8

RADIO DATA - GENERAL

428

SECTION 5. SURVEILLANCE SYSTEMS

ground-based air traffic surveillance sensors. TIS-B service will be available throughout the
NAS where there are both adequate surveillance coverage from ground sensors and ade-
quate broadcast coverage from ADS-B ground radio stations. The quality level of traffic infor-
mation provided by TIS-B is dependent upon the number and type of ground sensors availa-
ble as TIS-B sources and the timeliness of the reported data. (See FIG 4-5-8 and FIG 4-5-9.)

TIS-B Requirements.
In order to receive TIS-B service, the following conditions must exist:

1. Aircraft must be equipped with an ADS-B transmitter/receiver or transceiver, and a

cockpit display of traffic information (CDTI).

2. Aircraft must fly within the coverage volume of a compatible ground radio station that is

configured for TIS-B uplinks. (Not all ground radio stations provide TIS-B due to a lack
of radar coverage or because a radar feed is not available).

3. Aircraft must be within the coverage of and detected by at least one ATC radar serving

the ground radio station in use.

TIS-B Capabilities.

1. TIS-B is intended to provide ADS-B equipped aircraft with a more complete traffic pic-

ture in situations where not all nearby aircraft are equipped with ADS-B Out. This advi-
sory-only application is intended to enhance a pilot’s visual acquisition of other traffic.

2. Only transponder-equipped targets (i.e., Mode A/C or Mode S transponders) are trans-

mitted through the ATC ground system architecture. Current radar siting may result in
limited radar surveillance coverage at lower altitudes near some airports, with subse-
quently limited TIS-B service volume coverage. If there is no radar coverage in a given
area, then there will be no TIS-B coverage in that area.

TIS-B Limitations.

1. TIS-B is NOT intended to be used as a collision avoidance system and does not relieve

the pilot's responsibility to “see and avoid” other aircraft, in accordance with 14CFR
§91.113b. TIS-B must not be used for avoidance maneuvers during times when there is
no visual contact with the intruder aircraft. TIS-B is intended only to assist in the visual
acquisition of other aircraft.
NOTE: No aircraft avoidance maneuvers are authorized as a direct result of a TIS-B
target being displayed in the cockpit.

2. While TIS-B is a useful aid to visual traffic avoidance, its inherent system limitations

must be understood to ensure proper use.

(a) A pilot may receive an intermittent TIS-B target of themselves, typically when

maneuvering (e.g., climbing turns) due to the radar not tracking the aircraft as
quickly as ADS-B.

(b) The ADS-B-to-radar association process within the ground system may at times

have difficulty correlating an ADS-B report with corresponding radar returns from

RADIO DATA - GENERAL

429

SECTION 5. SURVEILLANCE SYSTEMS

the same aircraft. When this happens the pilot may see duplicate traffic symbols
(i.e., “TIS-B shadows”) on the cockpit display.

TIS-B position updates will occur approximately once every 3-13 seconds depend-
ing on the type of radar system in use within the coverage area. In comparison, the
update rate for ADS-B is nominally once per second.

(d) The TIS-B system only uplinks data pertaining to transponder-equipped aircraft.

Aircraft without a transponder will not be displayed as TIS-B traffic.

(e) There is no indication provided when any aircraft is operating inside or outside the

TIS-B service volume, therefore it is difficult to know if one is receiving uplinked
TIS-B traffic information.

3. Pilots and operators are reminded that the airborne equipment that displays TIS-B tar-

gets is for pilot situational awareness only and is not approved as a collision avoidance
tool. Unless there is an imminent emergency requiring immediate action, any deviation
from an air traffic control clearance in response to perceived converging traffic appear-
ing on a TIS-B display must be approved by the controlling ATC facility before com-
mencing the maneuver, except as permitted under certain conditions in 14CFR
§91.123. Uncoordinated deviations may place an aircraft in close proximity to other air-
craft under ATC control not seen on the airborne equipment and may result in a pilot
deviation or other incident.

Reports of TIS-B Malfunctions.
Users of TIS-B can provide valuable assistance in the correction of malfunctions by reporting
instances of undesirable system performance. Since TIS-B performance is monitored by
maintenance personnel rather than ATC, report malfunctions to the nearest Flight Service
Station (FSS) facility by radio or telephone, or by sending an email to the ADS-B help desk
at adsb@faa.gov. Reports should include:

1. Condition observed;
2. Date and time of observation;
3. Altitude and location of observation;
4. Type and call sign of the aircraft; and
5. Type and software version of avionics system.

FLIGHT INFORMATION SERVICE-BROADCAST (FIS-B)

Introduction.
FIS-B is a ground broadcast service provided through the ADS-B Services network over the
978 MHz UAT data link. The FAA FIS-B system provides pilots and flight crews of properly
equipped aircraft with a cockpit display of certain aviation weather and aeronautical informa-
tion. FIS-B reception is line-of-sight within the service volume of the ground infrastructure.
(See FIG 4-5-8 and FIG 4-5-9.)

4-5-9

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SECTION 5. SURVEILLANCE SYSTEMS

Weather Products.
FIS-B does not replace a preflight weather briefing from a source listed in Paragraph 7-1-2,
FAA Weather Services, or inflight updates from an FSS or ATC. FIS-B information may be
used by the pilot for the safe conduct of flight and aircraft movement; however, the informa-
tion should not be the only source of weather or aeronautical information. A pilot should be
particularly alert and understand the limitations and quality assurance issues associated with
individual products. This includes graphical representation of next generation weather radar
(NEXRAD) imagery and Notices to Airmen (NOTAM)/temporary flight restrictions (TFR).
REFERENCE—
AIM, Paragraph 7-1-11, Flight Information Services.
Advisory Circular (AC) 00-63, “Use of Cockpit Displays of Digital Weather and Aeronautical
Information”.

Reports of FIS-B Malfunctions.
Users of FIS-B can provide valuable assistance in the correction of malfunctions by reporting
instances of undesirable system performance. Since FIS-B performance is monitored by
maintenance personnel rather than ATC, report malfunctions to the nearest Flight Service
Station (FSS) facility by radio or telephone, or by sending an email to the ADS-B help desk
at adsb@faa.gov. Reports should include:

1. Condition observed;
2. Date and time of observation;
3. Altitude and location of observation;
4. Type and call sign of the aircraft; and
5. Type and software version of avionics system.

Table 4-5-3 — FIS-B Over UAT Product Update and Transmission Intervals

Product

Update Interval

Transmission

Interval (95%)

Basic
Prod-

uct

AIRMET

As Available

5 minutes

Yes

AWW/WW

As Available, then at

15 minute intervals for 1

hour

5 minutes

Ceiling

As Available

10 minutes

Convective SIGMET

As Available, then at

15 minute intervals for 1

hour

5 minutes

Yes

D-ATIS

As Available

1 minute

RADIO DATA - GENERAL

431

SECTION 5. SURVEILLANCE SYSTEMS

Table 4-5-3 — FIS-B Over UAT Product Update and Transmission Intervals (continued)

Product

Update Interval

Transmission

Interval (95%)

Basic
Prod-

uct

Echo Top

5 minutes

METAR/SPECI

1 minute (where availa-

ble), As Available other-

wise

5 minutes

Yes

MRMS NEXRAD (CONUS)

2 minutes

15 minutes

Yes

MRMS NEXRAD (Regional)

2 minutes

2.5 minutes

Yes

NOTAMs–D/FDC

As Available

10 minutes

Yes

NOTAMs–TFR

As Available

10 minutes

Yes

PIREP

As Available

10 minutes

Yes

SIGMET

As Available, then at

15 minute intervals for 1

hour

5 minutes

Yes

SUA Status

As Available

10 minutes

Yes

TAF/AMEND

6 Hours (±15 minutes)

10 minutes

Yes

Temperature Aloft

12 Hours (±15 minutes)

10 minutes

Yes

TWIP

As Available

1 minute

Winds Aloft

12 Hours (±15 minutes)

10 minutes

Yes

Lightning strikes

5 minutes

Yes

Turbulence

1 minute

15 minutes

Yes

Icing, Forecast Potential (FIP)

60 minutes

15 minutes

Yes

Cloud tops

30 minutes

15 minutes

Yes

1 Minute AWOS

1 minute

10 minutes

Graphical–AIRMET

As Available

5 minutes

Yes

Center Weather Advisory (CWA)

As Available

10 minutes

Yes

Temporary Restricted Areas (TRA)

As Available

10 minutes

Yes

Temporary Military Operations Areas
(TMOA)

As Available

10 minutes

Yes

The Update Interval is the rate at which the product data is available from the source.

RADIO DATA - GENERAL

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SECTION 5. SURVEILLANCE SYSTEMS

The Transmission Interval is the amount of time within which a new or updated product trans-
mission must be completed (95%) and the rate or repetition interval at which the product is
rebroadcast (95%).
The transmission and update intervals for the expanded set of basic meteorological products
may be adjusted based on FAA and vendor agreement on the final product formats and per-
formance requirements.

NOTE 1: Details concerning the content, format, and symbols of the various data link products
provided should be obtained from the specific avionics manufacturer.
NOTE 2: NOTAM-D and NOTAM-FDC products broadcast via FIS-B are limited to those issued
or effective within the past 30 days.

AUTOMATIC DEPENDENT SURVEILLANCE-REBROADCAST

(ADS-R)

Introduction.
ADS-R is a datalink translation function of the ADS-B ground system required to accommo-
date the two separate operating frequencies (978 MHz and 1090 ES). The ADS-B system
receives the ADS-B messages transmitted on one frequency and ADS-R translates and
reformats the information for rebroadcast and use on the other frequency. This allows ADS-B
In equipped aircraft to see nearby ADS-B Out traffic regardless of the operating link of the
other aircraft. Aircraft operating on the same ADS-B frequency exchange information directly
and do not require the ADS-R translation function. (See FIG 4-5-8 and FIG 4-5-9.)

Reports of ADS-R Malfunctions.
Users of ADS-R can provide valuable assistance in the correction of malfunctions by report-
ing instances of undesirable system performance. Since ADS-R performance is monitored
by maintenance personnel rather than ATC, report malfunctions to the nearest Flight Service
Station (FSS) facility by radio or telephone, or by sending an email to the ADS-B help desk
at adsb@faa.gov. Reports should include:

1. Condition observed;
2. Date and time of observation;
3. Altitude and location of observation;
4. Type and call sign of the aircraft; and
5. Type and software version of avionics system.

4-5-10

RADIO DATA - GENERAL

433

SECTION 5. SURVEILLANCE SYSTEMS

Information about Direction Finding Procedures published in this section is extracted from
ICAO Annex 10. It is provided for reference use only. The information is generally applica-
ble around the world. Regional variations may exist.

ICAO AERONAUTICAL TELECOMMUNICATION STANDARDS —

ANNEX 10

DIRECTION FINDING INTRODUCTORY NOTES

1. Direction-finding stations work either singly or in groups of two or more stations under the

direction of a main direction-finding station.

2. A direction-finding station working alone can only determine the direction of an aircraft in

relation to itself.

6.2.1 Recommendation — A direction-finding station working alone should give the following,
as requested:

1. true bearing of the aircraft, using the appropriate phrase;
2. true heading to be steered by the aircraft, with no wind, to head for the direction-finding sta-

tion using the appropriate phrase;

3. magnetic bearing of the aircraft, using the appropriate phrase;
4. magnetic heading to be steered by the aircraft, with no wind, to make for the station using

appropriate phrase.

6.2.2 Recommendation — When direction-finding stations work as a network to determine the
position of an aircraft, the bearing taken by each station should be sent immediately to the station
controlling the direction-finding network to enable the position of the aircraft to be determined.
6.2.2.1 Recommendation — The station controlling the network should, on request, give the
aircraft its position in one of the following ways:

1. position in relation to a point of reference or in latitude and longitude, using the appropriate

phrase;

2. true bearing of the aircraft in relation to the direction-finding station or other specified point

using the appropriate phrase, and its distance from the direction-finding station or point,
using the appropriate phrase;

3. magnetic heading to steer with no wind, to make for the direction-finding station or other

specified point using the appropriate phrase, and its distance from the direction-finding sta-
tion or point, using the appropriate phrase.

6.2.3 Aircraft stations shall normally make request for bearings, courses or positions, to the aer-
onautical station responsible, or to the station controlling the direction-finding network.
6.2.4 To request a bearing, heading or position, the aircraft station shall call the aeronautical
station or the direction-finding control station on the listening frequency. The aircraft shall then
specify the type of service that is desired by the use of the appropriate phrase.

6.2

RADIO DATA - GENERAL

434

DIRECTION FINDING PROCEDURES

6.2.5  In radiotelephony, an aircraft station which requests a bearing shall end the transmission
by repeating its call sign. If the transmission has been too short for the direction-finding station to
obtain a bearing, the aircraft shall give a longer transmission for two periods of the approximately
ten seconds, or alternatively provide such other signals as may be requested by the direction-find-
ing station.
6.2.5.1  In radiotelephony, an aircraft station which requests a bearing shall end the transmission
by repeating its call sign. If the transmission has been too short for the direction-finding station to
obtain a bearing, the aircraft shall give a longer transmission for two periods of the approximately
ten seconds, or alternatively provide such other signals as may be requested by the direction-find-
ing station.
NOTE: Certain types of VHF/DF stations require the provision of a modulated signal (voice trans-
mission) in order to take a bearing.
6.2.6  When a direction-finding station is not satisfied with its observation, it shall request the air-
craft station to repeat the transmission.
6.2.7  When a heading or bearing has been requested, the direction-finding station shall advise
the aircraft station in the following form:

1. the appropriate phrase;
2. bearing or heading in degrees in relation to the direction-finding station, sent as three fig-

ures;

3. class of bearing;
4. time of observation, if necessary.

6.2.8 When a position has been requested, the direction-finding control station, after plotting all
simultaneous observations, shall determine the observed position of the aircraft and shall advise
the aircraft station in the following form:

1. the appropriate phrase;
2. the position;
3. class of position;
4. time of observation.

6.2.9  As soon as the aircraft station has received the bearing, heading or position it shall repeat
back the message for confirmation, or correction.
6.2.10  When positions are given by bearing or heading and distance from a known point other
than the station making the report, the reference point shall an aerodrome, prominent town or
geographic feature. An aerodrome shall be given in preference to other places. When a large city
or town is used as a reference place, the bearing or heading, and the distance given shall be
measured from its center.
6.2.11  When the position is expressed in latitude and longitude, groups of figures for degrees
and minutes shall be used followed by the letter N or S for latitude and the letter E or W for longi-
tude, respectively. In radiotelephony the words NORTH, SOUTH, EAST or WEST shall be used.

RADIO DATA - GENERAL

435

DIRECTION FINDING PROCEDURES

LEGEND

The listings are in alphabetical sequence by country. The following information is provided:

Name

Official name (followed by location name, when different than navaid name).

Ident

Identifier.

Freq.

Frequency. VOR ghost frequency for TACAN or DME.

Class

The following codes are used:

VOR

TACAN (channels 17-59 and 70-126)

TACAN (channels 1-16 and 60-69)

DME

Terminal Class

High Altitude Class

Low Altitude Class

Class Unrestricted

Not co-located VOR and TACAN or DME

NDB (2000 watts or more)

NDB (50 - 1999 watts)

NDB (Less than 50 watts)

Used as LOM

Used as ILS back course locator

Locator (no class specified)

Marine Beacon

Voice capability:

Scheduled Weather Broadcast

No Voice on navaid frequency
(omitted on TACAN and DME facilities)

Automatic Transcribed Weather Broadcast

RADIO DATA - GENERAL

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NAVIGATION AIDS LEGEND

EXAMPLE:

(H) VORDME

(H) VORTAC

(H) TACAN

(T) VOR

(HH) NDB (2000 watts or more)

The letter “N” indicates that the VOR and TACAN or DME facility are separated by at least 6
seconds (one tenth of a minute) of either longitude or latitude. The TACAN (T) or DME (D)
facility class code is included with the VOR listing and the INS coordinates shown are for the
VOR facility. On the line immediately below this listing the TACAN or DME facility information is
listed with the TACAN or DME coordinates. To further highlight the difference in coordinates
TACAN or DME identifier is offset below the VOR identifier.

INS Coordinates In avionics keyboarding format, latitude and longitude in degrees, minutes and

tenths of minutes.

VAR/Stn Decl

Magnetic variation/station declination.

Elev.

Station elevation, shown only for those navaids with DME capability and if this
information is officially published by State authority.

ILS COMPONENTS

An ILS listing is provided at the end of each country listing. It is in alphabetical sequency by loca-
tion name, and includes both localizer and outer marker/locator information.

LOCALIZER AND OUTER MARKER/LOCATOR

LOCALIZER CLASS

LOCATOR/MARKER CLASS

LOC

Localizer

LOM

Locator Outer Marker

MLS

Microwave Landing System

Outer Marker

RADIO DATA - GENERAL

438

NAVIGATION AIDS LEGEND

LOCALIZER CLASS

LOCATOR/MARKER CLASS

SDF

Simplified Directional Aid

LDA

Localizer Directional Aid

PHONETIC ALPHABET AND MORSE CODE

LETTER WORD CODE

LETTER

WORD

CODE

LETTER WORD

CODE

Alfa

• —

Juliett

• — — —

Sierra

• • •

Bravo

— • • •

Kilo

— • —

Tango

—

Charlie

— • — •

Lima

• — • •

Uniform

• • —

Delta

— • •

Mike

— —

Victor

• • • —

Echo

•

November

— •

Whiskey

• — —

Foxtrot

• • — •

Oscar

— — —

X-ray

— • • —

Golf

— — •

Papa

• — — •

Yankee

— • — —

Hotel

• • • •

Quebec

— — • —

Zulu

— — • •

India

• •

Romeo

• — •

NUMERAL

CODE

• — — — —

• • — — —

• • • — —

• • • • —

• • • • •

— • • • •

— — • • •

— — — • •

— — — — •

— — — — —

RADIO DATA - GENERAL

439

NAVIGATION AIDS LEGEND

In this part of the METEOROLOGY section, selected Chapters and paragraphs have been
extracted from ICAO Annex 3 – Meteorological Service for International Air Navigation.
Chapter and paragraph numbers reflect those contained in the Annex.

CHAPTER 1 – DEFINITIONS

DEFINITIONS

Refer to INTRODUCTION/GLOSSARY.

TERMS USED WITH A LIMITED MEANING

For the purpose of Annex 3, the following terms are used with a limited meaning as indicated
below:

a. to avoid confusion in respect of the term “service” between the meteorological service con-

sidered as an administrative entity and the service which is provided, “meteorological author-
ity” is used for the former and “service” for the latter;

b. “provide” is used solely in connection with the provision of service;

c. “issue” is used solely in connection with cases where the obligation specifically extends to

sending out the information to a user;

d. “make available” is used solely in connection with cases where the obligation ends with

making the information accessible to a user;

e. “supply” is used solely in connection with cases where either c) or d) applies.

CHAPTER 2 – GENERAL PROVISIONS

OBJECTIVE, DETERMINATION AND PROVISION OF

METEOROLOGICAL SERVICE

2.1.1  The objective of meteorological service for international air navigation shall be to contrib-
ute towards the safety, regularity and efficiency of international air navigation.
2.1.2  This objective shall be achieved by supplying the following users: operators, flight crew
members, air traffic services units, search and rescue services units, airport managements and
others concerned with the conduct or development of international air navigation, with the mete-
orological information necessary for the performance of their respective functions.
2.1.3  Each Contracting State shall determine the meteorological service which it will provide to
meet the needs of international air navigation. This determination shall be made in accordance
with the provisions of this Annex and with due regard to regional air navigation agreements; it
shall include the determination of the meteorological service to be provided for international air
navigation over international waters and other areas which lie outside the territory of the State
concerned.
2.1.4  Each Contracting State shall designate the authority, hereinafter referred to as the mete-
orological authority, to provide or to arrange for the provision of meteorological service for interna-
tional air navigation on its behalf. Details of the meteorological authority so designated shall be

1.1

1.2

2.1

METEOROLOGY SERVICE FOR INTERNATIONAL AIR

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included in the State aeronautical information publication, in accordance with Annex 15, Chapter
5.
2.1.5 Each Contracting State shall ensure that the designated meteorological authority complies
with the requirements of the World Meteorological Organization in respect of qualifications and
training of meteorological personnel providing services for international air navigation.

SUPPLY, USE AND QUALITY MANAGEMENT OF METEOROLOGICAL

INFORMATION

2.2.1  Close liaison shall be maintained between those concerned with the supply and those con-
cerned with the use of meteorological information on matters which affect the provision of mete-
orological service for international air navigation.
2.2.2  Each Contracting State should ensure that the designated meteorological authority refer-
red to in 2.1.4 establishes and implements a properly organized quality system comprising proce-
dures, processes and resources necessary to provide for the quality management of the meteoro-
logical information to be supplied to users listed in 2.1.2.
2.2.3  Recommendation – The quality system established in accordance with 2.2.2 should be in
conformity with the International Organization for Standardization (ISO) 9000 series of quality
assurance standards, and certified by an approved organization.
NOTE: The ISO 9000 series of quality assurance standards provide a basic framework for the
development of a quality assurance programme. The details of a successful programme are to be
formulated by each State and in most cases are unique to the State organization. Guidance on
the establishment and implementation of a quality system is given in the Manual on the Quality
Management System for the provision of Meteorological Service to International Air Navigation
(Doc 9873).
2.2.4  Recommendation – The quality system should provide the users with assurance that the
meteorological information supplied complies with the stated requirements in terms of the geo-
graphical and spatial coverage, format and content, time and frequency of issuance and period of
validity, as well as the accuracy of measurements, observations and forecasts. Where the quality
system indicates that the meteorological information to be supplied to the users does not comply
with the stated requirements, and automatic error correction procedures are not appropriate, such
information should not be supplied to the users unless it is validated with the originator.
NOTE: Requirements concerning the geographical and spatial coverage, format and content, time
and frequency of issuance and period of validity of meteorological information to be supplied to
aeronautical users are given in Chapters 3, 4, 6 to 10 and Appendices 2, 3, 5 to 9 of Annex 3 and
the relevant regional air navigation plans. Guidance concerning the accuracy of measurement
and observation, and accuracy of forecasts is given in Attachments A and B respectively to Annex
3.
2.2.5  Recommendation – In regard to the exchange of meteorological information for opera-
tional purposes, the quality system should include verification and validation procedures and
resources for monitoring adherence to the prescribed transmission schedules for individual mes-
sages and/or bulletins required to be exchanged, and at the times of their filing for transmission.

2.2

METEOROLOGY SERVICE FOR INTERNATIONAL AIR

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The quality system should be capable of detecting excessive transit times of messages and bulle-
tins received.
NOTE: Requirements concerning the exchange of operational meteorological information are
given in Chapter 11 and Appendix 10 (not published herein) of Annex 3.
2.2.6  Demonstration of compliance of the quality system applied should be by audit. If non-con-
formity of the system is identified, action should be initiated to determine and correct the cause.
All audit observations should be evidenced and properly documented.
2.2.7  Owing to the variability of meteorological elements in space and time, to limitations of
observing techniques and to limitations caused by the definitions of some of the elements, the
specific value of any of the elements given in a report shall be understood by the recipient to be
the best approximation of the actual conditions at the time of observation.
NOTE: Guidance on the operationally desirable accuracy of measurement or observation is given
in Attachment A.
2.2.8  Owing to the variability of meteorological elements in space and time, to limitations of fore-
casting techniques and to limitations caused by the definitions of some of the elements, the spe-
cific value of any of the elements given in a forecast shall be understood by the recipient to be the
most probable value which the element is likely to assume during the period of the forecast. Simi-
larly, when the time of occurrence or change of an element is given in a forecast, this time shall
be understood to be the most probable time.
NOTE: Guidance on the operationally desirable accuracy of forecasts is given in Attachment B.
2.2.9  The meteorological information supplied to the users listed in 2.1.2 shall be consistent with
Human Factors principles and shall be in forms which require a minimum of interpretation by
these users, as specified in the following chapters.
NOTE: Guidance material on the application of Human Factors principles can be found in the
Human Factors Training Manual (Doc 9683).

NOTIFICATIONS REQUIRED FROM OPERATORS

2.3.1 An operator requiring meteorological service or changes in existing meteorological service
shall notify, sufficiently in advance, the meteorological authority or the aerodrome meteorological
office concerned.
2.3.2 The meteorological authority shall be notified by the operator requiring service when:

a. new routes or new types of operations are planned;
b. changes of a lasting character are to be made in scheduled operations; and

c. other changes, affecting the provision of meteorological service, are planned.

Such information shall contain all details necessary for the planning of appropriate arrangements
by the meteorological authority.

2.3

METEOROLOGY SERVICE FOR INTERNATIONAL AIR

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METEOROLOGICAL SERVICE FOR INTERNATIONAL AIR NAVIGATION - ANNEX 3

2.3.3 The operator or a flight crew member shall ensure that, where required by the meteorolog-
ical authority in consultation with users, the aerodrome meteorological office concerned, is noti-
fied:

a. of flight schedules;
b. when non-scheduled flights are to be operated;

c. when flights are delayed, advanced or cancelled.

2.3.4 Recommendation – The notification to the aerodrome meteorological office of individual
flights should contain the following information except that, in the case of scheduled flights, the
requirement for some or all of this information may be waived as agreed between the aerodrome
meteorological office and the operator concerned:

a. aerodrome of departure and estimated time of departure;
b. destination and estimated time of arrival;

c. route to be flown and estimated times of arrival at, and departure from, any intermediate aer-

odrome(s);

d. alternate aerodromes needed to complete the operational flight plan and taken from the rele-

vant list contained in the regional air navigation plan;

e. cruising level;

f. type of flight, whether under visual or instrument flight rules;

g. type of meteorological information requested for a flight crew member, whether flight docu-

mentation and/or briefing or consultation; and

h. time(s) at which briefing, consultation and/or flight documentation are required.

CHAPTER 3 – GLOBAL SYSTEMS, SUPPORTING CENTERS AND

METEOROLOGICAL OFFICES

NOTE: Technical specifications related to this Chapter are given in Appendix 2.

WORLD AREA FORECAST SYSTEM

The objective of the world area forecast system shall be to supply meteorological authorities and
other users with global aeronautical meteorological en-route forecasts in digital form. This objec-
tive shall be achieved through a comprehensive, integrated, worldwide and, as far as practicable,
uniform system, and in a cost-effective manner, taking full advantage of evolving technologies.

WORLD AREA FORECAST CENTERS

3.2.1 A Contracting State, having accepted the responsibility for providing a WAFC within the
framework of the world area forecast system, shall arrange for that center:

a. to prepare gridded global forecasts of:

1. upper wind;
2. upper-air temperature and humidity;

3.1

3.2

METEOROLOGY SERVICE FOR INTERNATIONAL AIR

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METEOROLOGICAL SERVICE FOR INTERNATIONAL AIR NAVIGATION - ANNEX 3

3. geopotential altitude of flight levels;
4. flight level and temperature of tropopause;
5. direction, speed and flight level of maximum wind;
6. cumulonimbus clouds;
7. icing; and
8. turbulence;

b. to prepare global forecasts of significant weather (SIGWX) phenomena;

c. to issue the forecasts referred to in a) and b) in digital form to meteorological authorities and

other users, as approved by the Contracting State on advice from the meteorological author-
ity;

d. to receive information concerning the release of radioactive materials into the atmosphere,

from its associated WMO Regional Specialized Meteorological Center (RSMC) for the provi-
sion of transport model products for radiological environmental emergency response, in
order to include the information in SIGWX forecasts; and

e. to establish and maintain contact with VAACs for the exchange of information on volcanic

activity in order to coordinate the inclusion of information on volcanic eruptions in SIGWX
forecasts.

3.2.2 In case of interruption of the operation of a WAFC, its functions should be carried out by
the other WAFC.
NOTE: Back-up procedures to be used in case of interruption of the operation of a WAFC are
updated by the Meteorology Panel (METP) as necessary; the latest revision can be found on the
ICAO METP website.

AERODROME METEOROLOGICAL OFFICES

3.3.1 Each Contracting State shall establish one or more aerodrome and/or meteorological
office which shall be adequate for the provision of meteorological service required to satisfy the
needs of international air navigation.
3.3.2 An aerodrome meteorological office shall carry out all or some of the following functions as
necessary to meet the needs of flight operations at the aerodrome:

a. prepare and/or obtain forecasts and other relevant information for flights with which it is con-

cerned; the extent of its responsibilities to prepare forecasts shall be related to the local
availability and use of en-route and aerodrome forecast material received from other offices;

b. prepare and/or forecasts of local meteorological conditions;

c. maintain a continuous survey of meteorological conditions over the aerodromes for which it

is designated to prepare forecasts;

d. provide briefing, consultation and flight documentation to flight crew members and/or flight

operations personnel;

3.3

METEOROLOGY SERVICE FOR INTERNATIONAL AIR

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METEOROLOGICAL SERVICE FOR INTERNATIONAL AIR NAVIGATION - ANNEX 3

e. supply other meteorological information to aeronautical users;

f. display the available meteorological information;

g. exchange meteorological information with other meteorological offices; and
h. supply information received on pre-eruption volcanic activity, a volcanic eruption or volcanic

ash cloud, to its associated air traffic services unit, aeronautical information service unit and
meteorically watch office as agreed between the meteorological, aeronautical information
service and ATS authorities concerned.

3.3.3 The aerodromes for which landing forecasts are required shall be determined by regional
air navigation agreement.
3.3.4 For an aerodrome without aerodrome meteorological office located at the aerodrome:

a. the meteorological authority concerned shall designate one or more aerodrome meteorologi-

cal office(s) to supply meteorological information as required;

b. the competent authorities shall establish means by which such information can be supplied

to the aerodromes concerned.

METEOROLOGICAL WATCH OFFICES

3.4.1 A Contracting State, having accepted the responsibility for providing air traffic services
within a flight information region (FIR) or a control area (CTA), shall establish, in accordance with
regional air navigation agreement, one or more MWOs, or arrange for another Contracting State
to do so.
3.4.2 An MWO shall:

a. maintain continuous watch over meteorological conditions affecting flight operations within its

area of responsibility;

b. prepare SIGMET and other information relating to its area of responsibility;

c. supply SIGMET information and, as required, other meteorological information to associated

air traffic services units;

d. disseminate SIGMET information;
e. when required by regional air navigation agreement, in accordance with 7.2.1:

1. prepare AIRMET information related to its area of responsibility;
2. supply AIRMET information to associated air traffic services units; and
3. disseminate AIRMET information.

f. supply information received on pre-eruption volcanic activity, a volcanic eruption and vol-

canic ash cloud for which a SIGMET has not already been issued, to its associated area
control center (ACC)/flight information center (FIC), as agreed between the meteorological
and ATS authorities concerned, and to its associated VAAC as determined by regional air
navigation agreement; and

3.4

METEOROLOGY SERVICE FOR INTERNATIONAL AIR

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g. supply information received concerning release of radioactive materials into the atmosphere,

in the area for which it maintains watch or adjacent areas, to its associated ACC/FIC, as
agreed between the meteorological and ATS authorities concerned, and to aeronautical
information service units, as agreed between the meteorological and appropriate civil avia-
tion authorities concerned. The information shall comprise location, date and time of the
release, and forecast trajectories of the radioactive materials.

NOTE: The information is provided by RSMCs for the provision of transport model products for
radiological environmental emergency response, at the request of the delegated authority of the
State in which the radioactive material was released into the atmosphere, or the International
Atomic Energy Agency (IAEA). The information is sent by the RSMC to a single contact point of
the national meteorological service in each State. This contact point has the responsibility of
redistributing the RSMC products within the State concerned. Furthermore, the information is pro-
vided by IAEA to RSMC co-located with VAAC London (designated as the focal point) which in
turn notifies the ACCs concerned about the release.
3.4.3 Recommendation – The boundaries of the area over which meteorological watch is to be
maintained by an MWO should be coincident with the boundaries of an FIR or a CTA or a combi-
nation of FIRs and/or CTAs.

VOLCANIC ASH ADVISORY CENTERS

3.5.1 A Contracting State, having accepted the responsibility for providing a VAAC within the
framework of the international airways volcano watch, shall arrange for that center to respond to a
notification that a volcano has erupted, or is expected to erupt or volcanic ash is reported in its
area of responsibility, by:

a. monitoring relevant geostationary and polar-orbiting satellite data and, where available, rele-

vant ground-based and airborne data, to detect existence and extent of volcanic ash in the
atmosphere in the are concerned;
NOTE: Relevant ground-based and airborne data include data derived from Doppler weather
radar, ceilometers, lidar and passive infrared sensors.

b. activating the volcanic ash numerical trajectory/dispersion model in order to forecast the

movement of any ash ‘cloud’ which has been detected or reported;
NOTE: The numerical model may be its own or, by agreement, that of another VAAC.

c. issuing advisory information regarding the extent and forecast movement of the volcanic ash

‘cloud’ to:

1. MWOs, ACCs and FICs serving FIRs in its area of responsibility which may be affected;
2. other VAACs whose areas of responsibility may be affected;
3. WAFCs, international OPMET databanks, international NOTAM offices, and centers

designated by regional air navigation agreement for the operation of aeronautical fixed
service Internet-based services; and

3.5

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JEPPESEN GENERAL AIRWAY MANUAL (Issue Date 1 JUL 21) - page 14