Relay of Flight Information from Air Traffic Service to Aircraft

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Relay of Flight Information from Air Traffic Service to Aircraft

52ND ANNUAL CONFERENCE, Bali, Indonesia, 24-28 April 2013

WP No. 92

Relay of Flight Information from Air Traffic Service to Aircraft

Presented by TOC


According to the ICAO SARPS, Air Traffic Services are required to provide flight information. Although it is not the most accurate and efficient method, it is often the Air Traffic Controller assuming the responsibility of broadcasting this information. Although several new techniques are being developed, suitable tools and techniques are not always available to the controller yet.

This paper gives information about current developments and implementations and proposes Policy regarding the development of new technologies.


1.1 According to the ICAO SARPS, Air Traffic Services are required to provide airspace users with information required for the safe and efficient conduct of flights.

1.2. The information to be relayed can be quite detailed and must be past in a timely manner, especially in the final stages of a flight.

1.3  In practice it is often the Air Traffic Controller who assumes this responsibility.

1.4  TOC was asked by the IFATCA Global Aerodrome Domain Team to study this subject in regard to ICAO provisions and controller responsibilities on relaying Flight Information from ground to aircraft.


2.1  The aviation operations are increasingly data driven and becoming more dependent on accurate and timely information exchange. Sector and runway capacity is also becoming more and more important, especially when performance is one of the key elements in successful operation in aviation. Nevertheless, performance is not only efficiency and minimum safe separation, but also requires the provision of flight information, which is necessary for the safe conduct of a flight.

2.2  Flight Information Service

2.2.1 ICAO Annex 11, Air Traffic Services:

Flight information service – A service provided for the purpose of giving advice and information useful for the safe and efficient conduct of flights.

2.9.2 Air traffic control units shall be established to provide air traffic control service, flight information service and alerting service within control areas, control zones and at controlled aerodromes.

Note. – The services to be provided by various air traffic control units are indicated in 3.2.

4.1 Application

4.1.1 Flight information service shall be provided to all aircraft which are likely to be affected by the information and which are:

a) provided with air traffic control service; or

b) otherwise known to the relevant air traffic services units.

Note.— Flight information service does not relieve the pilot-in-command of an aircraft of any responsibilities and the pilot-in-command has to make the final decision regarding any suggested alteration of flight plan.

4.1.2 Where air traffic services units provide both flight information service and air traffic control service, the provision of air traffic control service shall have precedence over the provision of flight information service whenever the provision of air traffic control service so requires.

Note.— It is recognized that in certain circumstances aircraft on final approach, landing, take-off and climb may require to receive without delay essential information other than that pertaining to the provision of air traffic control service.

4.2 Scope of flight information service

4.2.1 Flight information service shall include the provision of pertinent:

a) SIGMET and AIRMET information;

b) information concerning pre-eruption volcanic activity, volcanic eruptions and volcanic ash clouds;

c) information concerning the release into the atmosphere of radioactive materials or toxic chemicals;

d) information on changes in the availability of radio navigation services;

e) information on changes in condition of aerodromes and associated facilities, including information on the state of the aerodrome movement areas when they are affected by snow, ice or significant depth of water;

f) information on unmanned free balloons;

and of any other information likely to affect safety.

4.2.2 Flight information service provided to flights shall include, in addition to that outlined in 4.2.1, the provision of information concerning:

a) weather conditions reported or forecast at departure, destination and alternate aerodromes;

b) collision hazards, to aircraft operating in airspace Classes C, D, E, F and G;

c) for flight over water areas, in so far as practicable and when requested by a pilot, any available information such as radio call sign, position, true track, speed, etc., of surface vessels in the area.

4.2.3 Recommendation.— ATS units should transmit, as soon as practicable, special air-reports to other aircraft concerned, to the associated meteorological office, and to other ATS units concerned. Transmissions to aircraft should be continued for a period to be determined by agreement between the meteorological and air traffic services authorities concerned.

4.3 Operational flight information service broadcasts The meteorological information and operational information concerning radio navigation services and aerodromes included in the flight information service shall, whenever available, be provided in an operationally integrated form. Recommendation: VHF operational flight information service broadcast messages should contain the following information in the sequence indicated:

a) name of aerodrome;

b) time of observation;

c) landing runway;

d) significant runway surface conditions and, if appropriate, braking action;

e) changes in the operational state of the radio navigation services, if appropriate;

f) holding delay, if appropriate;

g) surface wind direction and speed; if appropriate, maximum wind speed;

*h) visibility and, when applicable, runway visual range (RVR);

*i) present weather;

*j) cloud below 1 500 m (5 000 ft) or below the highest minimum sector altitude, whichever is greater; cumulonimbus; if the sky is obscured, vertical visibility, when available;

k) air temperature;

l) dew point temperature;

m) QNH altimeter setting;

n) supplementary information on recent weather of operational significance and, where necessary, wind shear;

o) trend forecast, when available; and

p) notice of current SIGMET messages.

ICAO Doc 9694, Data Link Applications:

7.1 In a data link ATS system, flight-related information (e.g. meteorological information and situational awareness) can be made available to aircraft in digital form. This information will assist the pilot by increasing flight safety and improving situational awareness.

7.2 Most of this information is currently delivered to the aircraft via voice. It is expected that the use of data link to transmit flight information will be implemented in an evolutionary manner. In the future, it is expected that DFIS will provide information that is not currently available to the aircraft.

7.3 As the system evolves, flight information may be provided through addressed (point to point) or broadcast data link media.

2.2.2  According to the ICAO SARPS, Air Traffic control units need to be established for the provision of flight information in controlled airspace or at controlled aerodromes. In practice it is often the Air Traffic Controller assuming this responsibility.

2.2.3  Flight information enhances a lot of different sorts of meteorological and operational information which is currently often delivered to the flight crew by voice. Although several systems like the ATIS have reduced the controller’s workload, there is still a lot of information to be past and radio congestion could still be encountered when traffic volume increases. This additional task should be considered when determining ATC sector capacity. There are often unsuitable tools or techniques available to ATCOs to keep track of exactly what information was provided to each particular aircraft. The kind of information that was provided on a previous frequency or prior to a handover is normally not available to the ATCOs working the aircraft. This way pilots could be planning parts of the flight based on out of date information, which could lead to serious safety issues.

2.2.4 Developing new systems and techniques, focussing on providing essential flight information, could reduce RTF and workload and thereby increase safety. ANSPs, aerodrome operators and aircraft designers should work together to develop an extensive and accurate information provision tool. Several stakeholders (including Eurocontrol) are working on the Digital Aeronautical Information Management (D-AIM) concept. The concept is focusing on the provision of information sharing both from ground to ground as from ground to air. New technologies and systems are being developed, integrating AIM and Data Link communication.


2.3.1  IFATCA Policy is:

States should establish a common aeronautical information database containing:

1. Notices to Airmen (NOTAMs);

2. Aeronautical information Publication Data

3. Meteorological data;

4. Operational and technical status data which could be used by air navigation services systems for the efficient handling of aeronautical information and operational flight information


2.3.2  TOC still considers this Policy to be valid.

2.4 Automatic Terminal Information Service (ATIS)

2.4.1 ICAO Annex 11, Air Traffic Services:

4.3.6. Automatic terminal information service (voice and/or data link) Whenever Voice-ATIS and/or D-ATIS is provided:

a) the information communicated shall relate to a single aerodrome;

b) the information communicated shall be updated immediately a significant change occurs;

c) the preparation and dissemination of the ATIS message shall be the responsibility of the air traffic services;

d) individual ATIS messages shall be identified by a designator in the form of a letter of the ICAO spelling alphabet. Designators assigned to consecutive ATIS messages shall be in alphabetical order;

e) aircraft shall acknowledge receipt of the information upon establishing communication with the ATS unit providing approach control service or the aerodrome control tower, as appropriate;

f) the appropriate ATS unit shall, when replying to the message in e) above or, in the case of arriving aircraft, at such other time as may be prescribed by the appropriate ATS authority, provide the aircraft with the current altimeter setting; and

g) the meteorological information shall be extracted from the local meteorological routine or special report.

Note.— In accordance with Sections 4.1 and 4.3 of Appendix 3 to Annex 3, the surface wind direction and speed and runway visual range (RVR) are to be averaged over 2 minutes and 1 minute, respectively; and the wind information is to refer to conditions along the runway for departing aircraft and to conditions at the touchdown zone for arriving aircraft. A template for the local meteorological report, including the corresponding ranges and resolutions of each element, are in Appendix 3 to Annex 3. Additional criteria for the local meteorological report are contained in Chapter 4 of, and in Attachment D to, Annex 3.

2.4.2  IFALPA Technical Manual – Annex 11, Air Traffic Services:

4.3.6 Automatic Terminal Information Service (voice and/or data link)

ICAO sub-para. b) of para. states whenever Voice-ATIS and/or D-ATIS is provided the information communicated shall be updated immediately a significant change occurs;


This should be expanded to refer to significant changes in the aerodrome operational state or weather, and Notes should be added to the following effect:

1. A significant change in the aerodrome operational state means, for example, a change of runway, a change of serviceability of an approach aid, a change in braking action, etc. These changes should be assessed for their likely permanence before being including in the broadcast. A brief statement of the variability or tendency of a particular item may be given in the broadcast, and/or an indication that updated information will be given on the control frequency.

2. The issue of a special aerodrome report would require updating of the broadcast, but normally the broadcast should be changed with every routine aerodrome report. Changes in certain meteorological conditions may occur too rapidly to make it practicable to make continual amendments to the ATIS broadcasts, in order always to give current values of the element(s) involved. In such cases, the ATIS message should give the then current value(s) of the element(s) involved, together with an indication that rapid changes are taking place, and that current values will be given on the control frequency.

ICAO sub-para c) states that the preparation and dissemination of the ATIS message shall be the responsibility of the air traffic services.


It should be emphasised that the ATIS message should be prepared by qualified ATS or MET staff, and a Note should be added to this effect.

ICAO sub paragraph e) states that aircraft shall acknowledge receipt of the information upon establishing communication with the ATS unit providing approach control service or the aerodrome control tower, as appropriate; ICAO sub paragraph f) states that the appropriate ATS unit shall, when replying to the message in e) above or, in the case of arriving aircraft, at such other time as may be prescribed by the appropriate ATS authority, provide the aircraft with the current altimeter setting.


The appropriate ATS unit should provide arriving aircraft with the current altimeter setting at the time the aircraft is first cleared below a flight level to an altitude, for approach, or into the traffic pattern.

2.4.3  The reception of ATIS via data-link (D-ATIS), allows pilots to maintain their listening of ATC communications during critical high workload phases of flight, thus increasing the situational awareness and reducing the likelihood of distraction induced mistakes. Furthermore, depending on the traffic density and the complexity of the approach, it may assist flight crews with the Go Around /Landing decision making process by providing the latest changes to the runway condition and local weather, which is subject to the equipment being set up to allow this data to be pushed to the pilot automatically.


2.5.1  ICAO Annex 3, Meteorological Service for International Air Navigation:

VOLMET – Meteorological information for aircraft in flight.

Data link-VOLMET (D-VOLMET) – Provision of current aerodrome routine meteorological reports (METAR) and aerodrome special meteorological reports (SPECI), aerodrome forecasts (TAF), SIGMET, special air-reports not covered by a

SIGMET and, where available, AIRMET via data link.

VOLMET broadcast – Provision, as appropriate, of current METAR, SPECI, TAF and SIGMET by means of continuous and repetitive voice broadcasts.

9.5 Information for aircraft in flight

9.5.1 Meteorological information for use by aircraft in flight shall be supplied by a meteorological office to its associated air traffic services unit and through D-VOLMET or VOLMET broadcasts as determined by regional air navigation agreement. Meteorological information for planning by the operator for aircraft in flight shall be supplied on request, as agreed between the meteorological authority or authorities and the operator concerned.

11.5 Use of aeronautical data link service – contents of D-VOLMET

D-VOLMET shall contain current METAR and SPECI, together with trend forecasts where available, TAF and SIGMET, special air-reports not covered by a SIGMET and, where available, AIRMET.

Note.— The requirement to provide METAR and SPECI may be met by the data link- flight information service (D-FIS) application entitled “Data link-aerodrome routine meteorological report (D-METAR) service”; the requirement to provide TAF may be met by the D-FIS application entitled “Data link-aerodrome forecast (D-TAF) service”; and the requirement to provide SIGMET and AIRMET messages may be met by the D-FIS application entitled “Data link-SIGMET (D-SIGMET) service”. The details of these data link services are specified in the Manual of Air Traffic Services Data Link Applications (Doc 9694).

2.5.2  In practice a VOLMET message (also known as “en-route ATIS”) provides air crews with meteorological information of the main aerodromes near their destination. The message is broadcasted on HF and/or VHF frequencies and can be scheduled at a fixed time (every 30 minutes). As a result of a fixed time implementation pilots sometimes have to wait up to 30 minutes for the current broadcast.

2.5.3  D-VOLMET is an automated form of a VOLMET which enables the delivery of the VOLMET information to the cockpit via datalink. The information is broadcasted on request of the flight crew.

2.6 ANSP/Aerodrome Operator Example – Runway Reporting System

Some air navigation service providers and aerodrome operators have worked together to introduce ‘runway reporting systems’ (hardware, software applications and associated communications) to forward runway conditions information in real-time and in fixed format automatically to air traffic control and onward to flight crews. The main components of the systems are a continuous friction measurement device, and advanced pieces of software: one in a lap-top situated in the runway inspection vehicle, and the other on a server, which processes (possibly via 3G connection) transmitted information for various purposes.

2.6.1 Runway reporting systems forward information about the contaminants (e.g. snow and ice) on the runway surface, and about the level of friction. They can also produce SNOWTAM message and include in them, as a new feature, information regarding the operationally most significant contaminant on the runway. The information assists pilot decision-making to optimize safe takeoff s and landings. The advantage of these systems is that information reporting can be quicker and more consistent. An example of an operational runway reporting system is the one operated by Finavia.

2.7  NextGen – Weather Technology in Cockpit (WTIC)

One of the elements of NextGen is the Next Generation Network Enabled weather, where a national weather information system is designed to enable better air transportation decision-making. As a part of that several organisations are working on the Weather Technology in Cockpit (WTIC) programme. The programme objective is to reduce weather delays and cancellations by providing the aircrew with on board weather information, cockpit technologies and collaborative decision-making tools to enable safe and efficient flight in all weather conditions. By integrating decision support tools and direct machine-to-machine access the human interpretation of data is reduced.

2.8  Eurocontrol

2.8.1 European Action Plan Prevention Runway Incursions:

1.5. Air Navigation Service Provider Issues

1.5.7 Ensure that Air Traffic Control communication messages are not over long or complex –

Action: Air Navigation Service Providers – Guidance: Appendix A and Appendix E.

1.8 Aeronautical Information Management

1.8.5 Move towards digital aeronautical information management, to provide and use high quality data in an interoperable exchange format –

Action: Aerodrome Operator, Air Navigation Service Provider, Aeronautical Information Service Provider, Regulator, EUROCONTROL – Guidance: Appendix H.

2.8.2 In January 2013 Eurocontrol has issued the European Action Plan on the Prevention of Runway Excursions. The following is recommended to ANSPs on broadcasting information:

Review processes covering the provision of safety significant ‘essential’ aerodrome information such as weather, wind and runway surface conditions (e.g. when ‘wet’ or contaminated):

4a. To ensure a consistent, timely and accurate broadcast of aerodrome information.

4b. To ensure the integrity of the safety significant information supply chain from the provider (e.g. Met Office/Aerodrome Operator) to ATC/AISP and on to the flight crew.

4c. Consider equipping for digital transmission of ATIS, as appropriate.

4d. Ensure that training on the use of ATIS is provided to relevant operational staff (ANSP/AISP). Essential information is provided through 3 main types of media: Aeronautical Information Services (AIPs, NOTAMs etc); ATIS/D-ATIS; and radiotelephony. In certain circumstances, aerodrome signage can also supplement the written and/or oral data. More detailed guidance material covering Recommendation 4b and 4c can be found in the Aeronautical Information Service Providers section of the Action Plan. Furthermore, the Aircraft Operator and Aerodrome Operator sections also have complementary Recommendations and Guidance Material for Aircraft Operators and Aerodrome Operators related to the provision of safety significant “essential” information.

2.8.3 Eurocontrol is working on the CASCADE Programme (Cooperative ATS through Surveillance and Communication Applications Deployed in ECAC). The objective of this programme is to improve the productivity of Air Traffic Services through the introduction of new forms of communication, surveillance and automation. Several automation projects are already implemented (i.a.D-ATIS, delivery of Departure Clearance/DCL) or are planned to be implemented before 2020.

2.9 Datalink Operational Terminal Information Service (D-OTIS)

2.9.1  D-OTIS is a part of the Eurocontrol CASCADE Programme aiming at providing the flight crew with the widest possible range of data, especially for the departure, approach and landing phase of the flight. Flight crews can request compiled meteorological and operational flight information through D-OTIS related to any airport or TMA. This can be just an ATIS message or a whole set of data. The information is derived from ATIS, METAR and NOTAMs/SNOWTAMs and is updated when any of the components of the message change by specified criteria. D-OTIS could result in improved flight safety, a reduction in controller workload and voice channel congestion.

2.9.2  From December 2005 to mid-May 2006 a total of 38 aircraft participated in a D-OTIS trial in Belgium. NOTAMs from worldwide where available, but the D-ATIS was only limited to three airports in Belgium. Main goal of the trial was to demonstrate D-OTIS in real life operations and provide information on the possible benefits.

Outcomes of the trial were rather positive; the workload of flight crews was reduced and they were able to make appropriate decisions, especially in poor or changing weather. Although the actual amount of voice messages couldn’t be measured, it was subjectively predicted that the fewer requests of weather information reduce the controller’s workload.

2.10 Future possibilities

2.10.1 Datalink Runway Visual Range (D-RVR) ICAO Doc 9328, Manual of Runway Visual Range Observing and Reporting Practices:

11.2 Reporting Procedures

11.2.1 RVR information is included in local meteorological reports and in METAR/SPECI whenever either the visibility or RVR is observed to be less than 1500 m (see 5.2.3). These reports are passed to aircraft by ATS units, data link (i.e. D- ATIS, D-VOLMET) and/or aeronautical broadcasts (i.e. ATIS, VOLMET). They are also available through various dissemination systems to pilots and aeronautical personnel on the ground at the local aerodrome and at many other aerodromes for briefing or other purposes. In poor visibility flight crews currently rely on ATCO’s to get important up-to-date RVR information, which often provided via radiotelephony or on a broadcast frequency. If the RVR is (dropping) below published minima pilots are often not allowed to commence an instrument approach or they must execute a missed approach when in final approach phase.

If weather and visibility is changing quickly it is hard to keep track whether or not a flight crew has received the most up-to-date information. When airport capacity is decreasing and flights are encountering delays, flight crews often keep asking for visibility updates hereby causing frequency congestion. A part of the ideas in the Eurocontrol CASCADE Programme is a Datalink-RVR service. D-RVRs can enable RVR readouts referring to either the ATIS data in use or RVR- meters. It can be provided as an on-request service or automatically when updates occur. Currently D-RVR is not included in any specific development programme within CASCADE.

2.10.2 Datalink Surface Information & Guidance (D-SIG) ICAO Doc 4444, Air Traffic Management:

7.5 Essential information on aerodrome conditions

7.5.1 Essential information on aerodrome conditions is information necessary to safety in the operation of aircraft, which pertains to the movement area or any facilities usually associated therewith. For example, construction work on a taxi strip not connected to the runway-in-use would not be essential information to any aircraft except one that might be taxied in the vicinity of the construction work. As another example, if all traffic must be confined to runways, that fact should be considered as essential aerodrome information to any aircraft not familiar with the aerodrome.

7.5.2 Essential information on aerodrome conditions shall include information relating to the following:

a) construction or maintenance work on, or immediately adjacent to the movement area;

b) rough or broken surfaces on a runway, a taxiway or an apron, whether marked or not;

c) snow, slush or ice on a runway, a taxiway or an apron;

d) water on a runway, a taxiway or an apron;

e) snow banks or drifts adjacent to a runway, a taxiway or an apron;

f) other temporary hazards, including parked aircraft and birds on the ground or in the air;

g) failure or irregular operation of part or all of the aerodrome lighting system;

h) any other pertinent information.

7.5.3. Essential information on aerodrome conditions shall be given to every aircraft, except when it is known that the aircraft already has received all or part of the information from other sources. The information shall be given in sufficient time for the aircraft to make proper use of it, and the hazards shall be identified as distinctly as possible. D-SIG can provide operational graphical information like airport mapping, runway crossings, unavailable infrastructures etc. Before start-up or after arrival the information is sent as a map, which can be displayed in the cockpit. It’s also possible to integrate the taxi instructions (D-TAXI) in the display. Datalink Surface Information & Guidance is also a part of the Eurocontrol CASCADE programme, it is not included in any specific development programme yet.

2.10.3 Datalink Environment Data Service (D-ORIS) D-ORIS is automatically providing compiled meteorological and operational flight information in the en-route phase of flight. Currently the flight profile is computed before departure, with D-ORIS wind and temperature information can be uplinked on pilots request. The information is taken from NOTAMs, SIGMETs and other sources and is specifically relevant to an area to be over-flown.

2.11 Reservations

2.11.1  A lot of developments will most likely reduce controller workload. At some ATS Units, systems like D-ATIS are already implemented and in use, but it’s only an option running parallel to the normal ATIS broadcast. Not all aircraft are datalink equipped since the investments for airlines in datalink infrastructure are extremely high and the benefits are not that significant yet if the datalink is only used for information exchange. This might change as soon as CPDLC (Controller to Pilot DataLink Communications) will become more common.

2.11.2  The implementation of datalink services will probably reduce the controller workload but it also calls for clarity on the current distribution of responsibility. Nowadays the relay of flight information is completely the responsibility of an ATS center. But who will be responsible if pilots are receiving the information via datalink or on a fixed interval or on an on-request base. Does the Air Traffic Service still has to check which information is received or will it be the own responsibility of the flight crew? ICAO published requirements for inter alia D-VOLMET to comply to, but has not done this for every datalink service. Furthermore the different projects on automation are no completely clear about the new responsibility distribution. While the Eurocontrol Action Plan on the Prevention of Runway Excursions implies it is ATC who remains responsible (see par. 2.7.2), the new technologies seem to pass the information straight to the flight crew without the intervention of ATC. Also ICAO documents are not always completely clear about who is responsible to pass the information (for example par.; Doc 4444, 7.5.3. “Essential information on aerodrome conditions shall be given to every aircraft…”)

2.11.3 CPDLC messages are paid for individually. If the reception of up-to-date information becomes a flight crew responsibility this might create different handling standards between the airliners and could even lead to safety issues with flight crews not having received up-to-date information.


3.1  According to ICAO SARPs Air Traffic Control units shall be established to provide flight information service.

3.2  It is often the responsibility of the ATCO to provide relevant flight information, but this is not always the most efficient and accurate delivery method.

3.3  Increasing traffic density and thereby increased workload for ATCOs could complicate the broadcasting of essential flight information, which is required to safely conduct a flight. Furthermore, ATCOs do not always have tools and procedures to determine if pilots have received up to date flight information.

3.4  The development and introduction of new technologies and procedures could improve the delivery of flight information. Automated systems can provide more extensive and accurate information than is currently available and reduce controller workload and frequency congestion considerably.

3.5  Current rules lack of clarity about the responsibilities of the ATCO when datalink information systems are used.


It is recommended that:

4.1  IFATCA Policy is:

IFATCA encourages the development of technologies to automate the provision of Flight Information Service.

And is included in the IFATCA Technical and Professional Manual.

4.2  IFATCA Policy is:

When flight information is provided through automatic data transmission systems, clear procedures shall be established and the allocation of tasks and responsibilities shall be clearly determined.

And is included in the IFATCA Technical and Professional Manual.


ICAO – Doc 4444, Air Traffic Management.

ICAO – Annex 3, Meteorological Service for International Air Navigation.

ICAO – Annex 11, Air Traffic Services.

ICAO – Doc 4444 PANS/ATM.

ICAO – Doc 9365, All Weather Manual.

ICAO – Doc 9694, Data Link Application.

IFALPA – Technical Manual Annex 11, Air Traffic Services.

Eurocontrol – European Action Plan on the Prevention of Runway Excursions.

Eurocontrol – Interoperability Requirements Document, Air/Ground Cooperative ATS. (June, 2006).

Eurocontrol – D-AIM Deliverable 2, Architecture Description.

SITA – Air Traffic Services Datalink, description and locations. (November, 2012).

D-OTIS Trials, Final Report. (June, 2006).

Finavia –

Research Applications Laboratory –

Last Update: September 30, 2020  

May 2, 2020   316   Jean-Francois Lepage    2013    

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