Additional taxi-out time
|1.1 Contact organisation||EUROCONTROL: The European organisation for the safety of air navigation.|
|1.2 Contact organisation unit||Directorate Single Sky - Performance Review Unit (DSS/PRU)|
|1.3 Contact name||Performance Review Unit - EUROCONTROL|
|1.5 Contact mail address||96 Rue de la Fusée|
|1.6 Contact e-mail address||NSA-PRU-Support@eurocontrol.int|
|1.7 Contact phone number||+32 2 729 39 56|
|2. Metadata update|
|2.1. Metadata last certified||not applicable|
|2.2. Metadata last update||01 November 2016|
3. Statistical presentation
3.1. Data description
The additional taxi-out time is a proxy for the average departure runway queuing time on the outbound traffic flow, during congestion periods at airports.
It is the difference between the actual taxi-out time of a flight and a statistically determined unimpeded taxi-out time based on taxi-out times in periods of low traffic demand (see also related technical note).
Uncertainty of take-off clearance time and aircraft arriving time at runway holding stop bars makes traffic supply to runways a stochastic phenomenon. In order to ensure continuous traffic demand at runways and maximise runway usage, a minimum level of queuing is required. However, additional time is detrimental to taxi-out efficiency, fuel consumption and environment. Therefore, there exists a trade-off between taxi-out efficiency and runway throughput.
When monitoring taxi-out performance at airports, it is to be stressed that the goal is not to reduce taxi time to an unimpeded time - as this could negatively impact on runway throughput - but rather to reduce additional taxi-out time and associated fuel burn to the strict minimum.
As an output of the ATMAP Group, additional taxi-out time has been in use as a commonly agreed proxy for airport inefficiency in the taxi-out phase since 2008 and is compliant with the PI definition in the EU legislation.
3.2. Classification system
Additional taxi-out time is classified per Member State, with a breakdown for each airport subject to performance monitoring within the SES performance scheme.
3.3. Sector coverage
The measures pertain to the Air Transport and Air Traffic Management Sector of the economy.
3.4. Statistical concepts and definitions
The Taxi-out time is defined as the time spent by a flight between its actual off-block time (AOBT) and actual take-off time (ATOT).
The Unimpeded taxi-out time is an average taxi-out time when there is no congestion. There is one unimpeded time by departure airport, departure runway and departure stand.
The Additional taxi-out time is the difference between the actual taxi-out time and the unimpeded taxi-out time.
3.5. Statistical unit
The statistical unit is the airport. Airport level data is also aggregated to States.
3.6. Statistical population
The statistical population is the set of airports subject to performance monitoring within the SES performance scheme.
3.7. Reference area
The reference area is the Single European Sky Area.
3.8. Time coverage
2011 is the first year for which data is presented.
3.9. Base period
4. Unit of measure
Additional taxi-out time is measured in minutes per IFR departure [min/dep].
5. Reference period
- The first reference period (RP1) covers the calendar years 2012 to 2014 inclusive.
- The second reference period (RP2) covers the calendar years 2015 to 2019 inclusive.
Unless decided otherwise, the following reference periods shall be of five calendar years.
6. Institutional Mandate
Legal acts and agreements are established in the Performance Regulation (691/2010) and Commission Implementing Regulation (EU) No 390/2013.
- The information is disseminated in accordance with Article 21 of the Performance Regulation (691/2010).
- The information is disseminated in accordance with Article 22 of Commission Implementing Regulation (EU) No 390/2013.
8. Release policy
8.1. Release calendar
Taxi-out additional time data is released monthly with yearly aggregates.
8.2. Release calendar access
8.3. User access
Information is disseminated to the general public via the EUROCONTROL website.
9. Frequency of dissemination
Data is published monthly with the annual performance aggregate being available in January of the following year.
10. Dissemination format
The information is available on the EUROCONTROL website.
11. Accessibility of documentation
11.1. Documentation on methodology
As per the pertaining regulations (see Institutional Mandate).
For technical questions not addressed in Statistical processing please contact: NSA-PRU-Support@eurocontrol.int.
Additional definitions of the terms used in the frame of the this KPI are available in the Glossary.
11.2. Quality documentation
There is no specific documentation on procedures applied for quality management and quality assessment.
12. Quality Management
Although data providers are responsible for data quality, the EUROCONTROL Performance Review Unit performs data validation and quality checks.
12.1. Quality assurance
Data validation is performed by CODA, on behalf of PRU, on each data delivery by airports, and data validation report are returned to the data providers.
12.2. Quality assessment
Raw data is cross-checked with various sources (Network Manager, ANSP's, airport operators, airport coordinators and air carriers). A quality threshold is established, and data that does not pass the quality threshold is rejected.
If a field is found to be blank, it is tried to fill the missing value from an alternative data source (i.e. a missing aircraft type in the airport data flow can be filled with information from the Network Manager.
The data is collected for all the airports subject to performance monitoring within the SES performance scheme. Data completeness is determined each month as per the above-mentioned quality checks. Any missing data is reported to the provider.
The information is published for performance monitoring purposes in accordance with the relevant EU legislation.
14. Accuracy and reliability
14.1. Overall accuracy
The accuracy of the measure is influenced by the availability of the stand/runway configuration and the type of AOBT recording at the airports (manual vs. automated).
14.2. Sampling error
There is no sampling and therefore no sampling error.
15. Timeliness and punctuality
The information is published each month - in general around 30 days after the end of the month in question.
The internal databases are updated daily. The statistical processing is performed once per month.
16.1. Comparability — geographical
The data is collected centrally by the EUROCONTROL Performance Review Unit with delegation to CODA, and computed consistently for all airports subject to performance monitoring within the SES performance scheme.
The interpretation of the measure and comparisons across airports require due consideration of prevailing local circumstances (airport infrastructure, etc.).
16.2. Comparability over time
Comparison over time is valid.
17.1. Coherence — cross domain
Checks have been carried out with a number of airports and there is generally a good level of coherence between the indicator results and the results from performance measurement systems of airport operators.
17.2. Coherence — internal
Data is fully coherent from an internal perspective.
18. Cost and burden
19. Data revision
Subject to changes (i.e. infrastructure), there might be a need to change unimpeded times accordingly.
20. Statistical processing
20.1. Source data
In accordance with EU legislation, the data is collected centrally for all airports subject to performance monitoring within the SES performance scheme.
The input variables used for the calculation are detailed in the Statistical concepts and definitions section.
20.2. Frequency of data collection
The data is collected and transmitted for statistical processing on a monthly basis.
20.3. Data collection
20.4. Data validation
The data is validation as described in the Quality Management section.
20.5. Data compilation
Calculation of the indicator
- c, a combination of departure runway and group of stands, as described in the technical note for unimpeded taxi-out time,
- f(c) a flight characterised by a combination c,
- AcTXOT(f(c)) the actual taxi-out time for a flight f(c), i.e. the elapsed time between the off-block time (AOBT) of the flight f(c) and its actual take-off time (ATOT),
- UTXOT(c) the unimpeded taxi-out time for a combination c.
The additional taxi-out time AdTXOT(f(c)) is calculated for each flight f(c) as the difference between the actual taxi-out time AcTXOT(f(c)) of the flight and the unimpeded taxi-out time UTXOT(c) :
AdTXOT(f(c)) = AcTXOT(f(c)) - UTXOT(c)
The additional taxi-out time AdTXOT(c) for a given combination c is the average of the additional taxi-out time AdTXOT(f(c)) of all the flight f(c) characterised by that combination c.
The additional taxi-out time AdTXOT for a given airport is the weighted average of the additional taxi-out time AdTXOT(c), for all the combinations c at that airport with their probability of occurrence.
Corrections may be made when issues are discovered as described in the Quality Assessment section of this document.
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