Letter of Agreement

International Virtual Aviation Organisation

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Letter of Agreement

between Brindisi ACC (LIBB) Zagreb ACC (LDZO)

and IVAO Italy IVAO Croatia

Effective: 15/05/2017

Edition: 2


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1. Purpose

The purpose of this Letter of Agreement is to define the coordination procedures to be applied between

Brindisi ACC and Zagreb ACC when providing ATS to General Air Traffic (IFR/VFR) and Operational Air

Traffic on the IVAO Network.

These procedures are supplementary to those specified in ICAO, EUROCONTROL and national documents.

2. Areas of Responsibility

Vertical limits of Brindisi ACC are:

LIBB_ND_CTR GND – UNL

LIBB_EU_CTR FL 325 – UNL

LIBB_EL_CTR GND – FL 325

The ATS unit in charge of the Brindisi FIR and UIR is Brindisi Radar and it consists of one primary sector

(LIBB_ND_CTR) and two secondary sectors (LIBB_EU_CTR; LIBB_EL_CTR), which can be opened following

a priority detailed here.

Lateral limits of Brindisi ACC are shown on the diagram below:

http://ivao.it/phocadownload/ATC/LIBB/LIBB_vACC_briefing.pdf


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Vertical limits of Zagreb ACC are:

Above TMA Split FL205 – FL660

Above TMA Dubrovnik FL 205 – FL 660

Below above-mentioned lower limit FLs (and if above 1000 ft AGL) aircraft shall be transferred to the

respective ATS approach unit – Split Radar (LDSP APP), Dubrovnik Radar (LDDU APP).

Lateral limits of Zagreb ACC along with lateral limits of TMA Split and TMA Dubrovnik are shown on the

diagram below:

Red line depicts AOR between Zagreb ACC and respective TMAs and Brindisi FIR. Airspace between yellow

and green lines is shared between Split and Dubrovnik TMA. Airspace northwest of the yellow line is Split

TMA. Airspace southeast of the green line is Dubrovnik TMA. Airspace that is the southernmost and is

labelled Brindisi ACC is delegated to Brindisi ACC by Zagreb ACC between FL 325 and FL 460.

Split TMA

1000 ft AGL-FL205

Dubrovnik TMA

1000 ft AGL-FL205

Split<FL125

Dubrovnik FL125-FL205

Brindisi ACC

FL325-FL460


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3. ATS Units

Login name Callsign Frequency

LDZO_CTR Zagreb Radar 135.800

LDSP_APP Split Radar 120.875

LDDU_APP Dubrovnik Radar 123.600

LIBB_ND_CTR Brindisi (North) Radar 126.875

LIBB_EU_CTR Brindisi (East Upper) Radar 123.950

LIBB_EL_CTR Brindisi (Est Lower) Radar 128.300

4. Sectorization

4.1. Brindisi ACC and TMAs

LIBB_ND_CTR 126.875

GND – UNL „G“< FL195 „C“> FL195 – FL660

LIBB_EL_CTR 128.300

GND – UNL | If EU_CTR is available GND – FL325 „G“< FL195 „C“> FL195 – FL660

LIBB_EU_CTR 123.950

FL325 - FL660 „C“ FL660- UNL „G“


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4.2. Zagreb ACC and TMAs

Zagreb ACC has only one ACC sector (LDZO_CTR) and 2 TMA sectors bordering Brindisi FIR (Split and

Dubrovnik).

LDZO_CTR 135.800

1000 ft AGL – FL660 „D“<FL115 „C“>FL115 – FL660

LDSP_APP 120.875

1000 ft AGL – FL205 „D“< 7500 ft „C“> 7500 ft – FL205

LDDU_APP 123.600

1000 ft AGL – FL205 „D“< 7500 ft „C“> 7500 ft – FL205

5. Transfer of Control

Transfer of communication shall normally occur 2 (two) minutes before the aircraft reaches respective

Transfer of Control point (FIR boundary), and not later than reaching the TOC point.

Transfer of control occurs when the aircraft passes TOC point (FIR boundary). Transferring ATC unit is

responsible for the aircraft's vertical and horizontal separation until it passes the TOC point.

Traffic shall be handed over with a minimum horizontal separation of 10 nm between aircraft,

maintaining this distance or increasing (if necessary on parallel headings or by using speed control) or

1000 feet vertical separation (between RVSM approved aircraft, and aircraft below FL290) and 2000 feet

in other cases. Unless coordinated via IvAc Chat or IVAO Intercom or released as specified in this LoA, the

receiving ATC unit shall not give aircraft a clearance or instruction to climb or descend until it has passed

the TOC point.

Transferred aircraft are released for turns not greater than 45°.

6. ATS Routes, Coordination Points and Flight Level Allocation

6.1. Free Route Airspace

FRAIT (Free Route Airspace Italy) is available H24 from FL 335. If there is an airway after the Transfer

Point (this means that aircraft won’t enter in FRAIT airspace) traffic must be cleared at maximum FL 320

or FL 330.

Cross-border FRA procedures (SEAFRA – South East Axis Free Route Airspace) are available H24 from FL

325 up to FL 660 in the airspace formed from airspaces of Zagreb FIR/UIR, Sarajevo FIR and Beograd

FIR/UIR excluding areas where responsibility for the provision of ATS is delegated to ATS units other than

Zagreb ACC or Beograd ATCC and including area where responsibility for the provision of ATS is delegated

to Zagreb ACC.


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6.2. Cruise Flight Level Allocation

6.2.1. Flights from Zagreb ACC to Brindisi ACC

Waypoint designator FL Allocation

AIOSA ODD

KATTI EVEN

VELUG EVEN

XAMIT EVEN

XOLTA ODD

GISAM ODD

BEVIS ODD

6.2.2. Flights from Brindisi ACC to Zagreb ACC

Waypoint designator FL Allocation

AIOSA EVEN

GISAM EVEN

KATTI ODD

VAPUP ODD

XOLTA EVEN

BEVIS EVEN

6.3. Coordination for arrival/departure flights

Symbol explanation: ↓ = descending to (not levelled); ↑ = climbing to (not levelled); + = above; – = below

6.3.1. Flights arriving/departing Brindisi FIR

ATS Route COP/TOC FL Allocation Conditions

UP748 AIOSA ↓230 ARR LIBD

UL862 AIOSA ↓230 ARR LIBD

UL862 AIOSA ↓250 ARR LIBR

UM169 KATTI ↓220 ARR LIBP

UN924 VELUG ↓200 ARR LIBP


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P748 AIOSA ↑240 DEP LIBD

L862 AIOSA ↑240 DEP LIBD

L862 AIOSA ↑260 DEP LIBR

L5 VARUP ODD DEP LIBP

M169 KATTI ↑230 DEP LIBP

A48 BEVIS* ODD ARR LIBR/LIBD

A48 BEVIS* EVEN DEP LIBR/LIBR

*Temporary delegated area Italy AIP ENR6-1-1 / NOT indicated as specific FL too far from the A/D

6.3.2. Flights arriving/departing Zagreb FIR

DEST/DEP COP/TOC FL Allocation Conditions

DEST LDDU ALL ↓FL 150 -

DEST LDSP ALL ↓FL 150 -

7. VFR Flights

7.1. Brindisi FIR

Brindisi Information (LIBB_FSS) on 125.100 MHz frequency provides the Flight Information and Alert

Service.

If Brindisi Information is not online, the functions will be carried out by the appropriate ACC sector. In this

case the ATC service takes precedence over the FIS.

7.2. Zagreb FIR

Unless specially authorized by Zagreb ACC, VFR flights within FIR Zagreb shall not be operated above FL

195. Such special approval shall not be granted for enrouteVFR flights.

For departure and arrival from/to controlled and uncontrolled airports in Croatia VFR traffic shall use

VFR reporting points prescribed on the charts or in the VFR Manual Croatia.


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8. Validity

This Letter of Agreement becomes effective 15/05/2017, and supersedes the Letter of Agreement

between Brindisi ACC and Zagreb ACC dated 01/09/2009.

m.p. m.p.

ATC Ops Department – Italy Marko Bošnjak Brindisi FIR Staff Director – Croatia

Date: 05/05/2017


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A.1 Definitions

ATS Area of Responsibility

An airspace of defined dimensions where a sole ATS unit has responsibility for providing air traffic

services.

General Air Traffic (GAT)

All flights which are conducted in accordance with the rules and procedures of ICAO and/or the

national civil aviation regulations and legislation.

Operational Air Traffic (OAT)

All flights which do not comply with the provisions stated for GAT and for which rules and

procedures have been specified by appropriate national authorities.

Reduced Vertical Separation Minimum (RVSM)

A vertical separation minimum of 300 m (1 000 ft) which is applied between FL 290 and FL 410

inclusive, on the basis of regional air navigation agreements and in accordance with conditions

specified therein.

Release for Climb

An authorization for the accepting unit to climb (a) specific aircraft before the transfer of control. Note: The transferring unit/sector remains responsible within its Area of Responsibility for separation between the

transferred aircraft and other aircraft unknown to the accepting unit/sector, unless otherwise agreed.

Release for Descent

An authorization for the accepting unit to descend (a) specific aircraft before the transfer of

control. Note: The transferring unit/sector remains responsible within its Area of Responsibility for separation between the


Release for Turn

An authorization for the accepting unit to turn (a) specific aircraft away from the current flight

path by not more than 45° before the transfer of control. Note: The transferring unit/sector remains responsible within its Area of Responsibility for separation between the



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A.2 ATS Airspace Classification within Zagreb FIR


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A.3 SEAFRA Index Chart – Brindisi FIR and Zagreb FIR Border

Description of symbols: E = entry point; X = exit; A = arrival; D = departure; I = intermediate

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Letter of Agreement

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