Reference metadata describe statistical concepts and methodologies used for the collection and generation of data. They provide information on data quality and, since they are strongly content-oriented, assist users in interpreting the data. Reference metadata, unlike structural metadata, can be decoupled from the data.
Passenger, freight and flight traffic data is collected by State Airports Authority of Türkiye (DHMİ). In line with Regulation (EC) No 1358/2003, since reference year 2023 DHMI provides all datasets (A1, B1 and C1 datasets) to Eurostat.
There are responsible DHMI staff in the Airports for collecting air transport data. Main data suppliers are directly airlines or their handling agents. Commercial and total aircraft movement information is collected from the Air Navigation Service Units.
3.2. Classification system
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).
3.3. Coverage - sector
Data include commercial and civil air traffic of all Turkish airports.
Data of airports with less than 15,000 passenger units per year are also sent to Eurostat.
3.4. Statistical concepts and definitions
The main concepts used in this domain are the following:
Community airport - adefined 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.
3.5. Statistical unit
The data are collected at individual airport level. Statistics cover all airports in Türkiye open to commercial and civil air traffic.
For year 2021 data was collected from 56 airports in Türkiye.
3.6. Statistical population
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).
DHMI delivers all Airports including category ‘0’ in the statistics provided to Eurostat.
3.7. Reference area
Türkiye covering all regions of country.
3.8. Coverage - Time
Data has been reported starting from 2012 for flight stage A1 Dataset (passenger data only) and from 2001 for airport data C1 Dataset.
There is no data provided for on flight origin destination B1 Dataset.
Direct transit passenger data are available from 2001 and Transfer passenger data (monthly) are available from 2015.
3.9. Base period
Not applicable.
The units used depend on the variables collected within each data set and are: number of passengers, kilogrammes (for freight and mail), aircraft movements and passenger seats available.
According to the legal act the weight of freight and mail is transmitted in tonnes with three decimal places.
Reference period is the calendar year 2023.
Data is collected on a monthly basis for the purpose of data sets A1 and on annual basis for the purpose of data set C1.
6.1. Institutional Mandate - legal acts and other agreements
National level:
State Airports Authority (DHMI) Strategy and Planning Department Directive 11418 dated 2013 on data collection for air transport.
European level: until 2002, the data were provided to Eurostat on a voluntary basis; since 2002 data provision is based on an EP and Council framework legal act and on several implementing Commission Regulations:
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.
The data provided to Eurostat in the data sets A1 and C1 contain no confidential information.
Only the airline information data is subject to confidentiality. Before providing the data to Eurostat airline information is kept confidental .
The data provided to Eurostat in the data sets A1 and C1 contain no confidential information.
8.1. Release calendar
There is a national data release calendar announced by SAA and TurkStat on web to public covering airport data C1 dataset.
Statistics on Flight Stage data (Eurostat A1 Dataset) are not released to public on web and have no calendar release to public.
8.2. Release calendar access
Release Calendar is open to public access via TurkStat National Data Dissemination Calendar (UVYT) link under Airport Statistics title.
Also DHMI(SAA) provides timing of data release in a metadata file under Statistics section.
8.3. Release policy - user access
Data in scope of C1 Dataset is regularly released by DHMI for all public at same time in SAA web page as preliminary and final data.Also annual final data are provided by Turkstat on web to public. DHMI provides also Annual Statistical Book including data provided by Eurostat A1 Dataset free for its in-house use and with charged access to other users.
Release time and periodicity of DHMI data is pre-announced at TurkStat National Data Dissemination Calendar (UVYT): Tuik-gov website.). This is also announced by DHMI (SAA) via a metadata file presented within DHMI Statistics.
Air transport Statistics including A1, B1 and C1 datasets are delivered to Eurostat six months after the end of the reference period.
Preliminary monthly airport data of Turkey is published by DHMI every month after t + 45 days from end of reference month. Finalised monthly data published by SAA every 3 months after t+90 days from end of reference month.
Finalised annual data is published by DHMI and TurkStat once a year.
10.1. Dissemination format - News release
National monthly and annual data is published by DHMI as news releases.
DHMI also publish Annual Statistics Book which is not published on webbut available upon user request.
10.3. Dissemination format - online database
National monthly and annual data in scope of C1 dataset is published by DHMI as Excel files on-line: .
Annual final data of C1 datase are published also by Turkstat as Excel files.
10.4. Dissemination format - microdata access
Not applicable to air transport statistics.
10.5. Dissemination format - other
DHMI Annual Statistics Book cover detailed traffic data including data of Flight Stage A1 dataset as well as institutional data on airport infrastructure,budget , etc.
This book is not provided on-line but available free for DHMI’s in-house usage as well as by charge access for other users upon request.
10.6. Documentation on methodology
A Standard-documentation with Meta information (Definitions, comments, methods, quality) on Air Transport Statistics is available at national level.
National metadata file including definitions, release and access policies, methods, etc. are shared with public in DHMI web page.
10.7. Quality management - documentation
Data provider DHMI (SAA) holds ISO 9001:2.2015 Quality Management System Certificate dated 2022 valid until 2025.
DHMI has its own institutional quality policy and standards (documented for in-house use) with a focus on data analytics to monitor and improve its performance.
Turkish Civil Aviation Authority and TurkStat also provided Quality Approval Certificates to DHMI.
11.1. Quality assurance
Data consistency checks among different data sources, outlier analysis and validation checks are made by DHMI staff.
Eurostat mirror checks with partner European airports check some part of data quality. Eurostat Annual Quality reports monitor overall data quality.
11.2. Quality management - assessment
Implementation and compliance with the SDMX standards:
Currently CNA is able to generate data files in the SDMX standard. But, the TR system does not support the format so CNA uses the SDMX converter. Furthermore, for data exchanges CNA does not use SDMX standard with its data providers.
Regarding air passenger and flight traffic data, those are in high quality as indicated by Eurostat Quality Reports. Punctuality problems sometimes occur for data delivery to Eurostat. This is due to delays caused by data sources (airlines, handlers,etc.) due to incomplete data, staff problems for data-entry, etc. Lack of air freight data demanded by Eurostat A1 stem from the unavailability of data collection for transit freight data in Turkish airports due to operational problems. Lack of B1 dataset stems from software problems in data collection and data process.
For improving data quality, a new software system to form a fully harmonised and faster data collection practice among data sources is being developed and tested by DHMI.
12.1. Relevance - User Needs
At national level, statistics are used by government bodies as Ministry of Transport and Infrastructure, as well as aviation companies, academic researchers and press.
Data requests of users in line with statistcs of C1 Airport Dataset are provided by each airport on DHMI web. Data requests within concept of A1 and B1 Datasets are answered by DHMI upon request.
12.2. Relevance - User Satisfaction
DHMI’s Call Center and online request applications receive user requests and opinions on data. User feedbacks are responded by DHMI to users and also used for the improvement of statististics.
No User Satisfaction Survey has been implemented yet within DHMI.
12.3. Completeness
Since reference year 2023, all Datasets A1, B1 and C1 have completeness for passenger and freight statistics are produced and those datasets are transmitted to Eurostat by DHMI.
Datasets A1 and B1- possibility to identyfy the true first origin/ final destination of a passenger.
13.1. Accuracy - overall
Accuracy of passenger and flight statistics provided are high.
Various checks made by DHMI’s own system and checks among alternative sources eliminate possible data errors. Eurostat data transmission checks also support the quality of data provided. High data quality can be seen in Eurostat Annual Quality Reports and related mirror checks indicating a high accuracy level. Few revisions are asked by Eurostat for seat availability and aircraft type.
13.2. Sampling error
Not applicable for air transport data collection.
13.3. Non-sampling error
Cooperation and checks among partner data sources minimise non-response and data errors for passenger and flight data.
14.1. Timeliness
All the statistics required by the provisions of the Regulation 437/2003 are transmitted to Eurostat 4 months after the reference quarter.
Difficulties to respect deadline for data transmission:
It is feasible to deliver the datasets with a shorter delay (e.g. T+5).
DHMI view:
A1, B1 and C1 datasets required by the provisions of the Regulation 437/2003 are transmitted to Eurostat 6 months after the reference year.
Current data system disable data transfer within 4 months after reference quarter, so delay issues can occur. For the following years it can be possible to shorten data provision period.
14.2. Punctuality
All the statistics required by the provisions of the Regulation 437/2003 are available 2 months before the deadline for the data provisions set up in the legal act.
DHMI view:
Punctiality problems occur. Difficulties to match with deadlines are stemming from problems from various data sources.
DHMI is working for fast data delivery of data sources through a single data system under DHMI control.
15.1. Comparability - geographical
Comparable for all airports in Türkiye also comparable with Eurostat countries by statistical definitions.
15.2. Comparability - over time
C1 Dataset is comparable since year 2001.
A1 Dataset is comparable since year 2012.
A1 Dataset includes number of passenger flights and freight&mail only flights; whereas it excludes freight and mail volume by tonnes.
C1 Dataset includes number of passenger flights and freight&mail only flights as well as freight and mail volume by tonnes
Number of flights disseminated in all dissemination tables in Eurostat’s on-line database includes flights with freight and mail only.
15.3. Coherence - cross domain
Coherent with other national data sources as airline companies, handlers reports as well as international sources as Eurocontrol, etc.
15.4. Coherence - internal
A1 and C1 passenger and flight traffic data are coherent.
Number of flights disseminated in all dissemination tables in Eurostat’s on-line database includes flights with freight and mail only.
A1 Dataset includes number of passenger flights and freight&mail only flights; whereas it excludes freight and mail volume by tonnes.
C1 Dataset includes number of passenger flights and freight&mail only flights as well as freight and mail volume by tonnes.
DHMI staff at DHMI Headquarters and Turkish airports work daily to collect and process air transport data. For statististical publications and dissemination to Eurostat, monthly and annual extra work is done by staff at DHMI Headquarter. TurkStat staff also work for checks, revisions and publications on final annual data.
17.1. Data revision - policy
DHMI has data revision policy provided in tandem with TurkStat standarts.
DHMI revision policy include routine periodic data revisions.
For every 3 months published monthly preliminary data are revised to be published as final data. This revision is made through checks on data consistency and validation.
In cases where any errors are detected in finalized data, information is to be given to the public through the statistical announcements section of the DHMI website including where it is published, the data corrected and revised.
18.1. Source data
Dataset A1 – Data Suppliers (Passengers on board/Freight and mail on board)
Passengers on board : Handling Companies and Major Turkish Republic Registered Airlines
Freight and mail on board : No FS freight and mail
Aircraft Information in A1 :
ICAO Doc.8643
Seats information information in A1 :
Civil Aviation Authority share its seat capacity data by aircraft with DHMI. Any update on CAA data is obtained by handlers and airlines.
Dataset B1 –Data Suppliers (Passengers carried/Freight and mail loaded/unloaded)
Passengers on board : Handling Companies and Major Turkish Republic Registered Airlines
Datasets A1 and B1 - Use of Air Waybill Data as information source of freight data :
Passengers on board : Handling Companies and Major Turkish Republic Registered Airlines
Dataset C1 – Bodies that supply the direct transit information to the CNA :
Main data suppliers are directly airlines or their handling agents.
Dataset C1 – Bodies that supply the commercial and total aircraft movement to the CNA :
Commercial and total aircraft movement information is collected by from the Air Navigation Services Units.
18.2. Frequency of data collection
Daily, weekly or monthly according airport traffic magnitude.
Large traffic airports daily data collection others weekly or monthly.
DHMI is working to collect daily data with its new data system.
18.3. Data collection
Dataset A1 – Data supplier’s information sources (Passengers on board/ Freight and mail on board)
Data are coming from in the content of load&treem sheet.
Dataset A1 – Data transmission to CNA – level of aggregation, system and periodicity (Passengers on board/ Freight and mail on board)
Data from all airports are transmitted by servers to CNA on a monthly basis and at individual flight level.
Dataset B1 – Data supplier’s information sources (Passengers carried/ Freight and mail loaded/unloaded)
Data are coming from in the content of load&treem sheet.
Dataset B1 – Data transmission to CNA – level of aggregation, system and periodicity (Passengers carried/ Freight and mail loaded/unloaded)
Information not available.
Datasets A1 and B1 - OFOD data derived from FS data or collected separately by the data supplier :
Information not available.
Implementation of the data collection and compilation process :
Datasets A1 and C1 (Airports) data submission was a straightforward extension of an existing single process.
B1 require the implementation of a new data process system.
18.4. Data validation
Data validation procedure :
There are many validation procedures adapted into the system by process control. Some of them have been realized by automatic checks, others by manual controls with the several SQL sentences (airport, aircraft, airline code, mirror-check, etc.). If an error is detected, CNA contacts Airports and other data suppliers and then corrects it.
Description of consistency checks :
In connection with consistency checks for each reporting airport CNA checks total flights and total commercial aircraft movements. Origin airport should differ from destination Airport, number of passengers or volume of freight and mail should be greater than 0 for commercial movements. The main problem about consistency checks is that all constant data sources and documents (JP Fleets, ICAO Documents etc.) do not include all aircraft types and seat capacity.
18.5. Data compilation
After various plausibility checks, the data received from the airports are compiled into monthly data following the structure of the data sets which are preset by regulation (EC) 1358/2003.
Data codification practices :
There is no any codification problem in A1, B1 and C1 (Airports) data.
Problems on data compilation, validation and delivery :
Purpose of flight should clearly be identified by the Airlines in a standardized way. Receiving freight data breakdowns from Airlines and Handling Companies.
18.6. Adjustment
Not applicable for air transport data collection.
Not applicable.
Passenger, freight and flight traffic data is collected by State Airports Authority of Türkiye (DHMİ). In line with Regulation (EC) No 1358/2003, since reference year 2023 DHMI provides all datasets (A1, B1 and C1 datasets) to Eurostat.
There are responsible DHMI staff in the Airports for collecting air transport data. Main data suppliers are directly airlines or their handling agents. Commercial and total aircraft movement information is collected from the Air Navigation Service Units.
20 February 2025
The main concepts used in this domain are the following:
Community airport - adefined 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. Statistics cover all airports in Türkiye open to commercial and civil air traffic.
For year 2021 data was collected from 56 airports in Türkiye.
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).
DHMI delivers all Airports including category ‘0’ in the statistics provided to Eurostat.
Türkiye covering all regions of country.
Reference period is the calendar year 2023.
Data is collected on a monthly basis for the purpose of data sets A1 and on annual basis for the purpose of data set C1.
Accuracy of passenger and flight statistics provided are high.
Various checks made by DHMI’s own system and checks among alternative sources eliminate possible data errors. Eurostat data transmission checks also support the quality of data provided. High data quality can be seen in Eurostat Annual Quality Reports and related mirror checks indicating a high accuracy level. Few revisions are asked by Eurostat for seat availability and aircraft type.
The units used depend on the variables collected within each data set and are: number of passengers, kilogrammes (for freight and mail), aircraft movements and passenger seats available.
According to the legal act the weight of freight and mail is transmitted in tonnes with three decimal places.
After various plausibility checks, the data received from the airports are compiled into monthly data following the structure of the data sets which are preset by regulation (EC) 1358/2003.
Data codification practices :
There is no any codification problem in A1, B1 and C1 (Airports) data.
Problems on data compilation, validation and delivery :
Purpose of flight should clearly be identified by the Airlines in a standardized way. Receiving freight data breakdowns from Airlines and Handling Companies.
Dataset A1 – Data Suppliers (Passengers on board/Freight and mail on board)
Passengers on board : Handling Companies and Major Turkish Republic Registered Airlines
Freight and mail on board : No FS freight and mail
Aircraft Information in A1 :
ICAO Doc.8643
Seats information information in A1 :
Civil Aviation Authority share its seat capacity data by aircraft with DHMI. Any update on CAA data is obtained by handlers and airlines.
Dataset B1 –Data Suppliers (Passengers carried/Freight and mail loaded/unloaded)
Passengers on board : Handling Companies and Major Turkish Republic Registered Airlines
Datasets A1 and B1 - Use of Air Waybill Data as information source of freight data :
Passengers on board : Handling Companies and Major Turkish Republic Registered Airlines
Dataset C1 – Bodies that supply the direct transit information to the CNA :
Main data suppliers are directly airlines or their handling agents.
Dataset C1 – Bodies that supply the commercial and total aircraft movement to the CNA :
Commercial and total aircraft movement information is collected by from the Air Navigation Services Units.
Air transport Statistics including A1, B1 and C1 datasets are delivered to Eurostat six months after the end of the reference period.
Preliminary monthly airport data of Turkey is published by DHMI every month after t + 45 days from end of reference month. Finalised monthly data published by SAA every 3 months after t+90 days from end of reference month.
Finalised annual data is published by DHMI and TurkStat once a year.
All the statistics required by the provisions of the Regulation 437/2003 are transmitted to Eurostat 4 months after the reference quarter.
Difficulties to respect deadline for data transmission:
It is feasible to deliver the datasets with a shorter delay (e.g. T+5).
DHMI view:
A1, B1 and C1 datasets required by the provisions of the Regulation 437/2003 are transmitted to Eurostat 6 months after the reference year.
Current data system disable data transfer within 4 months after reference quarter, so delay issues can occur. For the following years it can be possible to shorten data provision period.
Comparable for all airports in Türkiye also comparable with Eurostat countries by statistical definitions.
C1 Dataset is comparable since year 2001.
A1 Dataset is comparable since year 2012.
A1 Dataset includes number of passenger flights and freight&mail only flights; whereas it excludes freight and mail volume by tonnes.
C1 Dataset includes number of passenger flights and freight&mail only flights as well as freight and mail volume by tonnes
Number of flights disseminated in all dissemination tables in Eurostat’s on-line database includes flights with freight and mail only.
