ENR 1.9.1.1.1   General (introduction)

ENR 1.9.1.1.2   Structure and responsibilities

The structure of the Network Manager encompasses:

1. the Flow Management Division (FMD), responsible for the planning co-ordination and implementation of ATFM measures within the FMD ATFM area
2. the Flight Data Operations Division (FDOD), which is responsible for collecting, maintaining and providing data on all flight operations and the air navigation infrastructure. FDOD includes the Integrated Flight Planning System (IFPS), as well as the ENV database where all operational airspace and network entities are defined.

NM is responsible for:

1. ensuring that traffic flows correspond to the stated capacities of the sectors through which they pass
2. ensuring that, when necessary, ATFM measures are applied in an equitable manner and in such a way as to reduce as far as possible the penalties to Aircraft Operators
   Post:

   Eurocontrol/DNM
   Rue de la Fusée 96
   1130 Brussels
   Belgium

   Tel:+322 729 9011

   Fax:+322 729 9043

The provision of the ATFM service in Croatia is carried out in accordance with the national Regulations stated in the Rules of the Air and ATS and other relevant publications.

All flights subject to ATFM will be treated equally, except for the flights with special status, which are either excluded or entitled priority. The ATFM measures will only be imposed if the number of notified flights exceeds available ATC capacity. Whenever ATFM measures are in force they are published by FMD in form of an ANM (ATFM Notification Message), ANM Flash and AIM (ATFM Information Message), which are all available in Central ARO Split.

A description of the ATFM area and information on the Network Operations Systems can be found in the Network Operations Handbook.

ENR 1.9.1.1.3   Responsibilities of Zagreb FMP

Zagreb FMP is responsible for coordination with NMOC on optimal use of ATFM measures, and as liaison between ATC, Aircraft Operators and the NM. Zagreb FMP is located in Zagreb ACC and is operational H24

Zagreb FMP address is:

Zagreb FMP
Croatia Control, Croatian Air Navigation Services, Ltd.
Rudolfa Fizira 2
10410 Velika Gorica, P.O.B. 103, Croatia

Phone: +385 1 6259 260

Fax: +385 1 6259 242

AFTN/AFS: LDZOZDFM

Zagreb FMP is responsible for the day to day monitoring, planning and co-ordination of all ATFM measures affecting air traffic which is entering, leaving, overflying or remaining within Croatia. The FMP is responsible for all co-ordination between ATC and the FMD and for providing ATFM support to Aircraft Operators.

Central ARO Split is responsible for the exchange of information between NMOC and Aircraft Operators who do not have a direct connection with Network Manager.

Furthermore, Central ARO Split is tasked to provide support to Aircraft Operators in the ATFM message interpretation and the routine message dialogue with NM, if required.

Full addresses and contact details of Central ARO Split is provided in AIP Croatia, GEN 3.3.6 ATS units address list.

ENR 1.9.1.1.4   Responsibilities of ATS

ATC have the following responsibilities:

1. ATC is responsible for departure slot monitoring at departure aerodromes. The exact procedures to be followed will depend on the way that ATS is organized at each aerodrome;
2. ATC units responsible for departure slot monitoring shall be provided with the necessary information concerning the restrictions in force and slots allocated;
3. ATC shall ensure that an ATFM slot, if applicable, is included as part of the ATC clearance;
4. ATC shall take account of an applicable slot or flight suspension when a clearance is issued;
5. ATC shall provide all possible assistance to Aircraft Operators to meet a CTOT or to co-ordinate a revised CTOT;
6. ATC may deny start up clearance to flights unable to meet their slots until co-ordination with the FMP/FMD has been effected and a revised CTOT issued.

ATC is also responsible for monitoring flights compliance with departure slots (CTOTs) issued by the FMD as detailed in the ATFM Handbook. A slot window of -5 to +10 minutes is available for ATC to optimize the departure sequence.

In accordance with the provision of the Regional Supplementary Procedures, Europe (ICAO Doc 7030), flights which do not adhere to their slot shall be denied start-up clearance. However, ATC shall make all efforts to enable departing flights to comply with the slot. ATC shall liaise with Zagreb FMP to co-ordinate extensions to CTOTs, in line with the procedure described in the NM Handbook, part ATFCM Users Manual.

With the progressive introduction of the Enhanced Tactical Flight Management System (ETFMS) and Flight Activation Monitoring (FAM), flights that are not notified as being airborne within 15 minutes of the notified ETOT or CTOT will receive a Flight Suspension (FLS) message. If a flight is suspended during the taxiing phase, then ATC is responsible for sending a DLA message.

For flights having already received their SLOT and being in a ready situation, the AO may ask the local ATC to send a ready message (REA). The flight will be considered as having a new EOBT at the time the REA message is received by the NM and may receive improvements accordingly

ENR 1.9.1.1.5   Responsibilities of Aircraft operators

Aircraft Operators shall inform themselves of and adhere to:

1. General ATFM procedures including flight plan filing and message exchange requirements;
2. Strategic ATFM measures (including Route Availability Document (RAD);
3. Current ATFM measures (including specific measures applicable on the day of operation, as promulgated by ANM or Flight Suspension (FLS) messages);
4. Departure slots (CTOTs) issued by the FMD and procedures related to changes to CTOTs;
5. the NM requirement for the modification or delay of EOBT. This is particularly important with the progressive implementation of Flight Activation Monitoring (FAM) whereby flights not notified as being airborne within 15 minutes of the notified ETOT or CTOT will receive a flight suspension message;
6. the sole responsibility to obtain a new CTOT if there is no RTF contact with the TWR at CTOT;
7. the correct procedure to be followed to obtain approval for the use of STS/ATFMX.

In order to comply with a CTOT, Aircraft Operators need to plan the departure of a flight so that the aircraft will be ready for start up in sufficient time to comply with a CTOT taking into account the taxi time shown in the Slot Allocation Message (SAM). A slot window is available to ATC to optimize the departure sequence.

Where a flight departs from an aerodrome with an ATSU, the Aircraft Operator or pilot shall obtain information, prior to start up from ATS as to whether a CTOT or FLS affects their flight.

Where a flight departs from an aerodrome without an ATSU it is the Aircraft Operator or pilot's responsibility to determine whether a CTOT or FLS affects their flight. In this case, the Aircraft Operator or pilot should contact the NM or the local FMP before the aircraft departs. For uncontrolled aerodromes within Croatia this information can also be obtained from Zagreb FIS on the address below:

Zagreb FIC
Phone: +385 1 6259503
FREQ: 135.050 MHZ
Callsign: Zagreb information

ENR 1.9.1.3.1   Rules for flight planning

The most important ATFM rules for flight planning, as defined in ICAO Doc 7030, are:

1. For flights likely to be subject to ATFM measures Aircraft Operators shall submit Flight Plans to IFPS at least 3 hours before the EOBT;
2. AOs filing flight plans for flights within the Network Management ATFM area or from within the ATFM adjacent area and entering the ATFM area shall assume their flight is subject to ATFM measures and subject to the requirement to submit a flight plan at least 3 hours before EOBT;
3. AOs should be aware that late filing of a flight plan may lead to a disproportionate delay;
4. Full details of flight planning requirements within the Network Management ATFM area are included in the Network Operations ATFM Users Manual;
5. It is also important that the EOBT of a flight is as accurate as possible. It is a European requirement that all controlled flights departing, arriving or overflying Europe subject to a change in an EOBT of more than +15 or -15 minutes shall notify the change to the NM through the IFPS. Modification procedures to enable Aircraft Operators to meet this requirement are described below.

In all cases, it is in the best interest of Aircraft Operators to initiate prompt revisions or cancellations, thus permitting the system to maximize use of available capacity and minimize delay. The later the revision is made the greater the probability of a delay. The correct application of the STS/ATFMX procedure will ensure that approved flights are not unnecessarily delayed.

ENR 1.9.1.3.3   Modification of Estimated Off Block Time (EOBT)

It is a requirement for both ATC and ATFM that the EOBT of a flight shall be an accurate EOBT. Any change to the EOBT of more than 15 minutes (+ or -) for any IFR flight within the NM Initial Flight Planning Zone (IFPZ) shall be communicated to IFPS.

An Aircraft Operator (AO) should not modify the EOBT to a later time simply as a result of an ATFM delay. When an AO submits an amendment message (eg DLA or CHG) to IFPS, they must always give as an EOBT the earliest EOBT they may comply with. This time is not directly related to the CTOT provided in the Slot Allocation Message (SAM) or Slot Revision Message (SRM). The EOBT should always reflect the time the AO wants to be off-blocks. The EOBT should always be changed if the original EOBT established by the AO cannot be met by the AO for reasons other than ATFM delay.

There are two categories of controlled flights covered by this procedure.

The procedure to be followed to modify the EOBT of a flight that has not received an ATFM CTOT is as follows:

1. To amend the EOBT to a later time, a DLA or CHG message shall be sent to IFPS;
2. To amend the EOBT to an earlier time, a CNL message must be sent to IFPS followed five minutes later by a new flight plan with new EOBT indicated.
   The replacement flight plan procedure shall not be used.

The procedure to be followed to modify the EOBT of a flight that has received an ATFM CTOT is as follows:

1. If the EOBT established by the AO has changed or is no longer realistic for reasons other than ATFM then the following procedure shall be used:
   1. If a flight has a CTOT that cannot be met, then the AO shall send a DLA message to IFPS with the new EOBT of the flight. This may trigger a revised CTOT;
   2. If a flight has a CTOT with some delay and the AO is aware that the original EOBT cannot be met but the existing CTOT is acceptable, then a message shall be sent to IFPS with the new EOBT of the flight. However, in order not to trigger a new CTOT, the following formula must be used:
      Take the current CTOT minus the taxi-time, minus 10 minutes. The new EOBT must not be after this time.
      However, as Network Operations Systems are continuously seeking to give zero delay, the CTOT of the flight will never be earlier than the new EOBT plus the taxi-time.
2. If a flight has had a CTOT and now receives a Slot Cancellation Message (SLC), but the original EOBT can no longer be met, then the AO shall communicate the new EOBT by use of a DLA message. ATC/ATFM will now have the 'true' EOBT of the flight.

ENR 1.9.1.3.4   ATFCM measures

A number of ATFM measures are available for aligning Traffic Demand (TD) with available ATC capacity. These include Re-routing or Flight Level Capping of particular flights or flows, Cherry-picking particular flights to keep them out of a particular ATC sector, and ultimately ATFM regulation. Routing ‘scenarios’ may be applied by the NM to help resolve particular problems on particular days. These involve recommended or mandatory routes for particular groups of flights or selected individual flights. Re-routes for groups of flights will be published by the NM in an AIM (Air Traffic Flow and Capacity Management Information Message) or ANM (ATFM Notification Message).

Aircraft Operators (AOs) complying with a re-route or level capping requirement shall cancel any existing flight plan and re-file on the new route in accordance with the Replacement Flight Plan procedure published in the IFPS Users Manual.

ENR 1.9.1.5.1   Flight Suspension – Procedures

When the AO and ATC at the aerodrome of departure receive an FLS due to the process, as described earlier, the following cases may occur:

1. The flight is still effectively on the ground either on stand or already taxiing:
   1. The AO (aircraft on stand) or ATC (aircraft already taxiing) should ensure that the flight plan is re-initiated by sending a DLA message with a correct EOBT. ETFMS (TACT) will then respond with a De-Suspension Message (DES) or Slot Revision Message (SRM) depending whether the flight is non-regulated or regulated, respectively.
   2. ATC should not let the aircraft start-up/depart before such a message (DES or SRM) is received.
      
      Note: All effort shall be made by ATC to ensure that all flights, regulated or not, comply with their ETOT/CTOTs, taking into account the respective taxiing/holding/sequencing requirements. Any exception to permit aircraft to continue for departure, following taxi delays caused by airfield congestion, is not applicable unless the aircraft can depart and be airborne within the time frame ETOT/CTOT + 15 minutes.
2. The flight is already flying:
   1. No action is needed from the AO or from the Tower of departure. The flight will automatically be de-suspended at the reception of one of the above messages (DEP, CPR, FSA etc).
      
      Note: The continuous re-occurrence of the above may mean a lack of proper information sent to NM. One possible solution would be a requirement to initiate DEP messages sent by the departure aerodrome but this will be determined by the NM through the national flow management office.

ENR 1.9.1.5.2   Area of Application

All users will be notified by NM/FMD by means of Air Traffic Flow and Capacity Management Information Message (AIM) whenever an area becomes FAM enabled. The effect of these areas being FAM-enabled means that all flights that are departing from or arriving at these areas will be affected by Flight Activation Monitoring. For flights departing from these areas and going to any other area, FAM will start at ETOT/CTOT.

For flights departing from non FAM-enabled and landing at aerodromes in FAM-enabled areas, the process will rely on the entry point of the first safely covered CPR-covered area. FLS may be sent to these flights landing inside, although departing outside.

ENR 1.9.1.7.1   Rules of Application for the use of STS/ATFMX

The following Rules shall be applicable to all flights seeking to gain exemption from ATFM measures within the area of responsibility of the NM. It is intended to ensure priority for flights which by the nature of their mission cannot under any circumstances be delayed due to ATFCM.

It should be noted by all users that any flight which obtains exemption, and which may have otherwise been delayed, will have that delay passed on to other flights. It is essential, therefore, that use of the exemption facility shall be properly controlled and monitored so that genuine flight priorities may continue to operate without ATFCM delay.

Croatian Civil Aviation Agency reserves the right to request evidence to determine the justification for the use of ATFMX status by operators.

ENR 1.9.2.5.1   Introduction

The Flexible Use of Airspace is an airspace management concept described by the International Civil Aviation Organization (ICAO) and developed by the European Organization for the Safety of Air Navigation (Eurocontrol), based on the principle that airspace should not be designated as purely civil or military, but rather as a continuum in which all user requirements are accommodated to the greatest extent possible.

The described airspace availability principle should be based on the efficiency of its usage and clearly defined airspace allocation priority rules, having regard to defense, public, economic, commercial, and private users’ needs.

Airspace Management (ASM) at Levels 2 and 3 is conducted by clear rules, procedures, and standards, to ensure a high level of airspace availability and usage efficiency, as well as all users’ safety.

The Collaborative Decision Making (CDM) process at ASM Levels 2 and 3 aims to ensure efficient airspace usage based on the priority rules criteria, which are made at the strategic ASM level. At Levels 2 and 3, airspace users, Approved Agencies, the Airspace Management Cell (AMC), the Flow Management Position, and the competent Air Traffic Control participate in the CDM process, whereas the decision on airspace allocation is made by the AMC after completing the CDM process.

During the planning and allocation process, priority rules for the reservation of airspace are applied, and in the negotiation procedures, reducing the negative impact of airspace reservations on air traffic should be taken into account.

On the day of activity, during the ASM Level 3 procedures (activation, deactivation, reservation cancellation, and urgent activity discontinuation request), special emphasis is placed on the complexity of weather conditions and real operational conditions in air traffic and airspace, to keep all airspace users safe.

For activities demanding airspace reservation in special circumstances, due to the nature of their occurrence and need for quick airspace access, airspace has to be ensured as soon as possible for the activities to be conducted, applying measures for the safety of other airspace users.

These priority rules are used by the AMC (Level 2) and air traffic controllers (Level 3) to properly allocate previously reserved airspace as well as to set priorities in special circumstances (at Level 3).

ENR 1.9.2.5.2   Priority Rules for Planned Activities at ASM Levels 2 and 3

Having regard to the national interests of the Republic of Croatia and users’ needs, the following priority list is laid down for planned activities requiring the reservation of airspace:

1. Control and protection of the state border of the Republic of Croatia and the Exclusive Economic Zone in the Adriatic Sea;
2. Aerial surveillance in the domain of police and customs tasks;
3. Protection of state authorities, critical infrastructure, and important persons;
4. Securing the area struck by a natural or technological disaster and/or catastrophe;
5. Celebrating state anniversaries, parades, and events organized by state administration bodies;
6. International military exercises and international exercises of other state administration bodies;
7. National military exercises and national exercises of other state administration bodies;
8. International air shows;
9. International aviation championships;
10. National aviation championships;
11. Military test flights;
12. Public interest activities (e.g. aerial work) conducted at the request of a competent state administration body;
13. Military and police training;
14. Training at the request of other state bodies;
15. Civil training flights;
16. Commercial manned aircraft aerial work operations;
17. Commercial unmanned aircraft aerial work operations;
18. Sports and recreational activities of manned aircraft and parachute jumps;
19. Sports and recreational activities of unmanned aircraft;
20. Releasing and launching objects into the atmosphere (e.g. unmanned free balloons, children’s balloons, sky lanterns, fireworks, lighting effects...);
21. Experimental activities for educational purposes.

If more users submit a request for the same portion of airspace for an activity to be conducted at the same time and of the same priority level, the requested airspace will be allocated to the user whose request was submitted first. Alternatively, two or more users can agree to work together in the same airspace at the same time if they clearly designate the user responsible for the allocated airspace.

In case of unforeseen events, the AMC can decide to discontinue activities in reserved airspace in the following situations:

• Emergency flights;
• Flights of Croatian military aircraft for the protection of sovereignty of the Republic of Croatia (STS/PROTECTED);
• Search and rescue flights and humanitarian flights (STS/SAR/HUM);
• Medical flights transporting sick or injured persons requiring emergency medical assistance, including the flights for the purpose of providing emergency medical assistance to sick or injured persons, as well as flights transporting transplants, blood, and medication, including the flights for boarding patients, medication, transplants or blood at the destination (STS/HOSP);
• Flights for heads of states (STS/HEAD) and flights for prime ministers and other state officials with the established preferential status (STS/STATE);
• Interception training flights of Croatian military aircraft;
• Securing the area struck by a natural or technological disaster and/or catastrophe;
• Urgent police and customs operations.

For this purpose, all airspace users reserving airspace structures shall submit to the Airspace Management Cell the contact details of the person responsible/head of activities who shall be available for the Airspace Management Cell via a means of communication (mobile or fixed line) for the whole duration of the activity.
Observation flights according to international agreements binding on the Republic of Croatia are prioritized pursuant to the agreement in force.

ENR 1.9.2.5.3   Priority Rules in Special Circumstances

The AMC must, by establishing an ad hoc structure, in the most suitable way for the given airspace situation, restrict or prohibit flights and activities in a specific volume of airspace for all except the approved users in the following cases:

1. At the written request of competent state administration bodies, if necessary for the safety of air traffic and other airspace users’ activities, due to the defense needs of the Republic of Croatia, military and police operations, search and rescue operations, fire control, the protection of state institutions, critical infrastructure and important persons, the protection from the emissions of hazardous and/or harmful substances, gases and phenomena, the Croatian state border control and protection, and the celebration of state anniversaries, parades and events organized by state administration bodies,
2. Due to real operational requirements for a period not longer than 48 hours, if necessary for the safety of air traffic and other airspace users’ activities, due to the defense needs of the Republic of Croatia, military and police operations, search and rescue operations, fire control, the protection of state institutions, critical infrastructure and important persons, the protection from the emissions of hazardous and/or harmful substances, gases and phenomena, the Croatian state border control and protection, and the celebration of state anniversaries, parades and events organized by state administration bodies.

At the request of the AMC, and for the purpose of informing all airspace users, the air navigation service provider shall publish all relevant information in the manner customary in air traffic.

The air navigation service provider shall, at the written request of competent state administration bodies or the Croatian Civil Aviation Agency, temporarily prohibit or restrict flights in a specific portion of airspace or at a specific aerodrome, by issuing a navigational warning, if necessary for defense or national security needs or the safety of (an) aircraft or in case of major natural disasters, according to the international agreements binding on the Republic of Croatia or immediately if necessary due to special circumstances, and publish it in the manner customary in air traffic.
Activities conducted in special circumstances are prioritized over all other airspace activities.

When establishing Ad-hoc structures in special circumstances, the AMC shall follow this priority list for allocating reserved airspace:

1. Protection of sovereignty of the Republic of Croatia,
2. Protection of state authorities, critical infrastructure, and important persons,
3. Securing, inspecting, and controlling an area struck by a natural or technological disaster and/or catastrophe,
4. Search and rescue at the request of a competent state administration body,
5. Police and customs operations,
6. Control of the state border and the Exclusive Economic Zone,
7. Unforeseeable operations by a competent state administration body.

ENR 1.9.2.7.1   AMC Portal System

The AMC Portal System is a centralized Airspace Management (ASM) tool, serving as an ASM system for publishing information as a publicly available IT system through which the provider of ASM services publishes information to its users on the restrictions and prohibitions in airspace. To utilize all the functions of the AMC Portal System, users are required to register on the Portal’s website.
The details on airspace reservations will be available to registered users only.

ENR 1.9.2.7.2   Informing of Users

Airspace users are informed about restrictions and prohibitions in airspace via Aeronautical Information Products and via the AMC Portal System. The AMC Portal System displays the actual occupancy of airspace in real time as well as the approved Airspace Use Plan and its amendments for the following period (AUP - Airspace Use Plan / UUP - Updated Airspace Use Plan / NUP - National Airspace Use Plan). The reservation of permanent structures published in the AIP of the Republic of Croatia is published by the AUP, UUP and/or NUP messages via the AMC Portal. For Zagreb FIR, detailed national AUPs and UUPs (NUPs) are issued via the ASM system for publishing information (the AMC Portal System).
The AMC publishes information regarding the flight operations of Unmanned Aircraft Systems via the AMC Portal, which serves as a publicly available system with the function of providing the Common Information Service.

ENR 1.9.2.7.3   Automatized Procedure for Establishing Ad-hoc Structures

This procedure is conducted via the AMC Portal Mobile application in real time on the day of activity of UAS flight operations if those operations are conducted within the UAS Approved Geographical Zone (UAG).

ENR 1.9.2.8.1   UAS Geographical Zones

UAS Geographical Zones are zones determined by a competent body to facilitate, restrict or prohibit UAS operations, in order to take into account the risks related to safety, privacy, personal data protection, security or the environment that stem from those operations. To enable and facilitate the informing of airspace users on the status of UAS Geographical Zones, the following airspace structures are introduced:

1. UAS Restricted Geographical Zone (URG): A part of airspace above a geographical zone determined by a competent body that is conditionally prohibited for UAS operations, but not for other aircraft and flight activities. UAS flight activities in this zone can be approved as an exception, in line with the laid down ASM procedures. In the context of the FUA concept, URG zones are established through the laid down ASM procedure, and, depending on the nature of the request, can be established temporarily or permanently at an appropriate ASM level.
2. UAS Limited Geographical Zone (ULG): A part of airspace above a geographical zone determined by a competent body that is restricted for UAS operations, depending on the characteristics of the UAS, type of allowed operations and/or the procedure for the approval of flight operations itself. Within this zone, an approval for conducting flight operations can be granted in line with the laid down ASM procedures. In the context of the FUA concept, ULG zones are established through the laid down ASM procedure, and depending on the nature of the request, can be established temporarily or permanently at an appropriate ASM level.
3. UAS Approved Geographical Zone (UAG): A part of airspace above a geographical zone determined by a competent body within which UAS operations can be conducted by the shortened procedure for the approval of flight operations. Within this zone, an approval for conducting UAS flight operations can be granted through the automatized procedure by a competent authority or service provider.

The following geographical zones are established in the control zone (CTR):

1. URG Zone – Within airspace bounded by the distance of 1500 M from the security fence of controlled aerodromes and 500 M laterally along the approach surface axis to the distance of 3500 M from the runway threshold;
2. ULG Zone – Within controlled airspace, higher than 50 M above ground or the surface of water outside of the URG zone;
3. UAG Zone – Within controlled airspace, MAX up to 50 M from ground level or the surface of water outside of the URG zone.

The following geographical zones are established outside of the control zone (CTR) and within Croatian airspace:

1. ULG Zone – Typically, higher than 120 M above ground level, and
2. UAG Zone – From ground level or the surface of water up to 120 M.

To conduct UAS operations in the vicinity of uncontrolled aerodromes, at distances shorter than 1500 M from the edges and 500 M laterally along the approach surface axis up to the distance of 2500 M from the runway threshold, prior consent of the operator of the uncontrolled aerodrome has to be obtained.
By the method of their publication, UAS Geographical Zones can be permanent or temporary, and they are shown on the AMC Portal. Permanent geographical zones are published in the AIP, ENR 6 “En-route charts”.

ENR 1.9.2.8.2   Establishing U-space

U-space airspace is a geographical zone established for conducting UAS flight operations, in which operations are permitted only with the support of U-space services.
U-space airspace can be established for security, safety, privacy or ecological reasons, and to propose its establishment, an airspace risk assessment has to be made.