Croatian Bureau of Statistics

Spatial Statistics Directorate

Transport Statistics Department

Ilica 3, 10000 Zagreb, Croatia

The statistics on commercial aviation covers scheduled and non-scheduled air traffic at the nine Croatian airports open for public transport of passengers and freight: Zagreb, Split, Dubrovnik, Pula, Rijeka, Zadar, Osijek, Brač and the Mali Lošinj.

Data on traffic in airports includes traffic of aircraft movements, passengers and freight by carriers, by type of traffic, traffic of aircrafts, passengers and freight by partner airports, transfer passengers. Data have been calculated using data collected at airport level. Data on traffic in airports are provided by airport operators. Data for statistics are generated from the operational airport information system and records containing all necessary variables and classifications. Data are transmitted to the Croatian Bureau of Statistics in electronic form following the agreed data structure and format.

 The statistics are compiled and transmitted monthly to Eurostat by the Croatian Bureau of Statistics.

The data collection follows the provisions of the following legal acts:

 National:

• Annual Implementation Plan of Statistical Activities of the Republic of Croatia
• Official Statistics Act ( Official Gazette, No 25/2020 )
• Programme of Statistical Activities of the Republic of Croatia

EU:

• Regulation (EC) N°1358/2003, implementing Regulation N°437/2003 of the European Parliament and of the Council on statistical returns in respect of the carriage of passengers, freight and mail by air.

Three data sets required by the Regulation – A1, B1 and C1 – are provided to Eurostat:

Dataset A1 - Flight Stage dataset: periodic flight stage data registered for airport-to-airport routes, and broken down by arrivals/departures, scheduled/non-scheduled, passenger service/all-freight and mail service, airline information and aircraft type. The values provided concern passengers on board, freight and mail on board, commercial air flights as well as passenger seats available.

Dataset B1 - On Flight Origin/Destination dataset: periodic on flight origin/destination data registered for airport-to-airport routes, and broken down by arrivals/departures, scheduled/non-scheduled, passenger service/all-freight and mail service and airline information. The values provided concern passengers carried and freight and mail loaded or unloaded.

Dataset C1 - Airport dataset: periodic airport data registered for declaring airports. The values provided concern total passengers carried, total direct transit passengers, total transfer (indirect transit) passengers (optional variable), total freight and mail loaded or unloaded, total commercial aircraft movements and total aircraft movements.

Data sets A1, B1 and C1 are provided on monthly basis. Airports handling less than 15 000 passenger units annually are not included in the data sets.

Data has been reported to Eurostat starting from 2008 for flight stage and on flight origin destination data and from 2004 for airport data.

When comparing Croatian air transport statistics data published by Eurostat with the results of the National Statistics Institute, it has to be considered, that national published data include two of the airports that are under 15 000 units threshold (Brač and Mali Lošinj).

For more information, please refer to publications with corresponding methodological explanations available at www.dzs.hr, which is prepared for the data collection at national level.

Dataset A1 and B1- data storage

Monthly datasets at flight level aggregation are stored in electronic archives form 2008 onwards, indefinitely.

Airports are classified according to ICAO (International Civil Aviation Organization) airport coded as listed in ICAO document 7910.

Aircrafts are classified according to aggregated aircraft categories based on the ICAO aircraft codes as listed in ICAO document 8643.

Airlines are classified according to the ICAO airline codes as listed in the ICAO document 8585. When providing the data to Eurostat, the region where they are licensed is coded accordingly either as European Union (EU) or outside the European Union (non-EU).

Air transport – commercial air services and civil aircraft movements for the airports open for public traffic.

Data relate to all airports open for public transport of passengers and freight: Zagreb, Split, Dubrovnik, Pula, Rijeka, Zadar, Osijek, Brač and the Mali Lošinj.

The information includes data on Croatian and foreign air operators, performing flights from and to airports on Croatian territory.

The main concepts used in this domain are the following:

Community airport - a defined area on land or water in a Member State subject to the provisions of the treaty, which is intended to be used either wholly or in part for the arrival, departure and surface movement of aircraft and open for commercial air services.

Flight stage - the operation of an aircraft from take-off to its next landing. This is linked to the definition of passengers (or freight and mail) on board.

Passengers on board - all passengers on board of the aircraft upon landing at the reporting airport or at taking off from the reporting airport. All revenue and non-revenue passengers on board an aircraft during a flight stage. Includes direct transit passengers (counted at arrivals and departures).

Direct transit passengers - passengers who, after a short stop, continue their journey on the same aircraft on a flight having the same flight number as the flight on which they arrive.

Transfer of indirect transit passengers - passengers arriving and departing on a different aircraft within 24 hours, or on the same aircraft bearing different flight numbers. They are counted twice: once upon arrival and once on departure.

Freight and mail on board - all freight and mail on board of the aircraft upon landing at the reporting airport or at taking off from the reporting airport. All freight and mail on board an aircraft during a flight stage. Includes direct transit freight and mail (counted at arrivals and departures). Includes express services and diplomatic bags. Excludes passenger baggage.

On flight origin and destination - traffic on a commercial air service identified by a unique flight number subdivided by airport pairs in accordance with point of embarkation and point of disembarkation on that flight. For passengers, freight or mail where the airport of embarkation is not known, the aircraft origin should be deemed to be the point of embarkation; similarly, if the airport of disembarkation is not known, the aircraft destination should be deemed to be the point of disembarkation. This is linked to the definition of passengers carried and freight and mail loaded or unloaded.

Passengers carried - all passengers on a specific flight (with one flight number) counted once only and not repeatedly on each individual stage of that flight. All revenue and non-revenue passengers whose journey begin or terminates at the reporting airport and transfer passengers joining or leaving the flight at the reporting airport. Excludes direct transit passengers.

Freight and mail loaded or unloaded - all freight and mail loaded onto or unloaded from an aircraft. Includes express services and diplomatic bags. Excludes passenger baggage. Excludes direct transit freight and mail.

Passenger unit - one passenger unit is equivalent to either one passenger or 100 kilograms of freight and mail.

The data are collected at individual airport level. Data providers are airport operators.

Data relate to the airports in Zagreb, Split, Dubrovnik, Pula, Rijeka, Zadar, Osijek, Brač and Mali Lošinj.

Four categories of Community airports are defined by the Regulation (EC) N°1358/2003:

• Category "0": Airports with less than 15 000 passenger units per year are considered as having only "occasional commercial traffic" without obligation to report.
• Category "1": Airports with between 15 000 and 150 000 passenger units per year shall transmit only aggregated airport data (Data set C).
• Category "2": Airports with more than 150 000 passenger units and less than 1 500 000 passenger units per year shall transmit flight stage data, on flight origin destination data as well as aggregated airport data (Data sets A, B and C).
• Category "3": Airports with at least 1 500 000 passenger units per year shall transmit flight stage data, on flight origin destination data as well as aggregated airport data (Data sets A, B and C).

Airports under category ‘0’ are not included in the statistics provided to Eurostat.

Airports open for public traffic on the territory of the Republic of Croatia.

All datasets have been provided according to the legal act starting from 2008 reference year.

Not applicable.

The units used depend on the variables collected within each data set and are: number of passengers, tonnes (for freight and mail), number of aircraft movements and passenger seats available.

According to the legal act the weight of freight and mail is transmitted in tonnes as rounded figures.

Data on freight and mail is provided in tonnes already rounded to full numbers. Distinguish than between ':' and '0' in the dissemination table avia_gor_hr: ':' means no freight transport (real zero), while '0' means freight and mail of less than 0.5 tonnes.

 Data is collected on a monthly basis for the purpose of data sets A1 and B1 and C1. Reference period is the calendar year 2023.

National level:

• Annual Implementation Plan of Statistical Activities of the Republic of Croatia
• Official Statistics Act (Official Gazette, No 25/2020)
• Programme of Statistical Activities of the Republic of Croatia

European level: until 2008, the data were provided to Eurostat on a voluntary basis; since 2008 data provision is based on an EP and Council framework legal act and on several implementing Commission Regulations:

• Regulation (EC) No 437/2003 of the European Parliament and of the Council of 27 February 2003 on statistical returns in respect of the carriage of passengers, freight and mail by air.
• Commission Regulation (EC) No 1358/2003 of 31/07/2003.
• Commission Regulation No 546/2005 of 8 April 2005.
• Commission Regulation No 158/2007 of 16 February 2007.

Not applicable.

National level:

• Official Statistics Act (OG, No. 25/2020.)

European level:

• Regulation (EC) No 223/2009 on European statistics (recital 24 and Article 20(4)) of 11 March 2009 (OJ L 87, p. 164), stipulates the need to establish common principles and guidelines ensuring the confidentiality of data used for the production of European statistics and the access to those confidential data with due account for technical developments and the requirements of users in a democratic society.

Only the airline information data is subject to confidentiality. Before providing the data to Eurostat, the region where they are licensed is coded accordingly either as European Union (EU) or outside the European Union (non-EU).

The data provided to Eurostat in the data sets A1, B1 and C1 contain no confidential information.

Data confidentiality problems: 

Information on airlines is confidential.

Air transport statistics is published monthly 45 days after the reference month in the form of a first release.

Release dates are publicly available in the release calendar of the CBS. Since release dates are planned sometimes far in advance, changes of dates might occur in both directions. Therefore, the Release Calendar is updated continually. Consult CBS web site under Calendar of Statistical Data Issues.

Statistical information is disseminated according to the Publication porgramme available under Calendar of Statistical Data Issues part at the web site of Croatian Bureau of Statistics.

In line with the Community legal framework and the European Statistics Code of Practice Croatian Bureau of Statistics disseminates statistics on traffic in airports respecting professional independence and in an objective, professional and transparent manner in which all users are treated equitably. Main results of commercial aviation statistics are available free of charge to all users. At the release data air transport statistics is available to all users at the same time.

Air transport statistics first results are published monthly 45 days after the reference month and annual publication of detailed data.

The First Release "Traffic in airports" - monthly data

Aggregated data on the level of the Republic of Croatia on the total number of aircraft operations, number of passengers and tons of freight, passenger traffic at airports and top ten countries by traffic of passengers realised with Croatian airports.

Exemple of First Release publication: Traffic in Airports, 2023.

More publications can be found under First Releases and Stat. Reports by Subject part at CBS web site.

• The First Release "Traffic in airports" - monthly data.
• Statistical Information - annual data

All the publications can be found under RELEASED DATA part on the CBS web site.

Data is not published in online databases.

Not applicable to air transport statistics.

Statistics in Line – monthly data on passenger and freight traffic at the level of the Republic of Croatia, annual detailed data on aircraft, passenger and freight traffic in airports, commercial traffic in airports, airport performance and employees at airports.

Statistical information – annual data on traffic of passengers

Publications with corresponding methodological explanations available at CBS web site, which is prepared for the data collection at national level.

The data on quality are stored in the CBS database of quality information (DBQI).

The main tool for the systematic quality assessment and quality management is the CBS database on quality information (DBQI). The DBQI has in first stage the Basic analytical tool for comparative analyses of quality indicators and later will contain Advanced analytical tool for comparative analyses of quality indicators.

An organisational structure and tools are in place to deal with quality. There are procedures in place to plan, monitor and improve the quality of the statistical processes. Procedures based on quality reporting are in place to internally monitor product quality. Results are analysed regularly and improving actions are undertaken, if needed (for example after obtaining annual summary results and mirror checks reports from Eurostat). There is a regular and thorough review of the key statistical outputs.

Implementation and compliance with the SDMX standards: 

The CBS delivers monthly datasets in the SDMX standard since June 2014 (for reference month April 2014) onwards.

Original data are generated from the data production system as Excel files that are modified to comply with the SDMX structure, converted and delivered to Eurostat.
SDMX standard for data exchanges is not used with data providers. Data providers deliver data as a flat file via e-mail.

The key users of air transport statistics are National Accounts Department, State institutions, enterprises, research and scientific community, journalists etc.

User satisfaction survey is not conducted.

The data collection on air transport statistics follows the provisions of the Regulation 437/2003. All variables in all three data sets are provided including the voluntary variable – transfer passenger.

External users expressed interest in true O/D data, but for the time being they are not collected by CBS.

Overall accuracy of the air transport statistics data is good. The processing with implemented logical and computational control, plausibility checks as well as checks done before transmitting data to Eurostat provides a high accuracy of the data. Comparisons with published data by the airports as well as mirror checks for national flights are regularly made and show a high level of comparability.

Not applicable for air transport data collection.

By working closely with the relevant departments of the airports and using all the implemented checks during data processing (logical computational controls, coherence checks and inter-dataset checks performed as well as mirror analysis of national traffic) and the legal obligation of airports to cooperate and report the data, misclassifications, under- or over-coverage can be excluded.

All the statistics required by the provisions of the Regulation 437/2003 are transmitted to Eurostat 2 months after the reference month.

No difficulties in respecting deadlines for the data transmissions.

All the statistics required by the provisions of the Regulation 437/2003 are available 4 months before the deadline for the data provisions set up in the legal act.

Since the statistical survey is fully harmonized with the statistical standards in the European Union: the Regulation (EC) No 437/2003 of the European Parliament and of the Council of 27 February 2003 on statistical returns in respect of the carriage of passengers, freight and mail by air as well as with all its amending regulations and as the common concepts and rules are applied, as well as in other Member States, it is possible to compare the statistical data between the Republic of Croatia and other Member States.

Comparable data harmonized with the statistical standards in the European Union the Regulation (EC) No 437/2003 are available since 2008 for all datasets. Aggregated airport data (dataset C1) are available from 2004.

Comparisons with other transport statistics are possible to some extent and used in monthly data production.

Source of comparison: monthly figures on the total number of aircraft operations and passenger and cargo traffic published on the airport web sites are partially comparable with the statistics on traffic of aircrafts, passengers and cargo in airports. Variables for comparison: total movements of aircrafts, passengers carried, transit passengers, cargo carried.

When comparing Croatian air transport statistics data published by Eurostat with the results of the National Statistics Institute, it has to be considered, that national published data include two of the airports that are under 15 000 units threshold (Brač and Mali Lošinj).

The response burden is put on airport operators that use operational airport software to generate the data required for statistical purposes. The use of operational data minimises the burden, data are delivered via e-mail and reporting units are contacted only to clarify the errors that cannot be solved by the CBS.

Provisional figures are not published in this survey and therefore regular revisions are not planned.

Deadline for the publication of first monthly results of traffic in airports is 45 days after the end of the month.

Provisional figures are not published in this survey and therefore regular revisions are not planned. Unplanned revisions are caused by events that could not be predicted and that are impossible to prevent (subsequent changes in data sources or subsequently identified errors in previously submitted data) are generally disseminated as soon as possible.

Data on traffic in airports are provided by airport operators. Data for statistics are generated from the operational airport information system and records containing all necessary variables and classifications.

Data are collected monthly.

Data are transmitted to the Croatian Bureau of Statistics in electronic form following the agreed data structure and format.

In statistical data processing, the CBS implements control of the data coverage for the purpose of checking the completeness of the submitted data. Logical-computational controls, data consistency between data sets and controls of used codes are checked at the lowest level of received data (aggregated to flight level).

Overview of data series, mirror analysis and comparison of results with other sources are carried out at the aggregate level of the airport.

Data validation procedure:

The validations are following:
- airport, aircraft, airline code check
- accordance between passenger/freight service and number of passengers/freight tonnage check
- accordance between passenger seats and number of passengers check
- accordance between passenger seats and type of aircrafts check
- codes ZZZZ (unknown aircraft, airline or destination) for big aircrafts and schedule air service check
- data series checks for three consecutive years at airport level check
- indices on the same period of the previous year at airport level check
When errors are detected results are sent back to the airports for explanation or correction and new files are provided after correction at airport level.

Description of consistency checks:

Data coherence between datasets A1, B1 and C1 at airline and airport level is checked.

Mirror check of the national traffic.

After various plausibility checks, the data received from the airports are compiled into monthly data following the structure of the data sets which are present by regulation (EC) 1358/2003.

Data codification practices:

Airports use IATA/ICAO codes alternatively, so trans-codification is made by airports before delivery to the CBS.

Problems on data compilation, validation and delivery:

There are no problems in the data compilation and validation process at the CBS and in the data transmission to Eurostat.

Not applicable for air transport data collection.

There are no additional comments.