Flight Completeness Checks: A Verifier’s Perspective

The basic approach is common across the different aviation schemes: 

Operator flight data → Independent third-party data → Flight-level reconciliation → Investigation of discrepancies → Verification of scope and exemptions 

Although the regulatory scope differs between the European Union Emissions Trading Scheme (EU ETS), United Kingdom Emissions Trading Scheme (UK ETS), ReFuelEU Aviation, Non-CO₂ Aviation Effects and Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), the fundamental verification principle remains the same: the verifier needs to achieve reasonable assurance that the population of relevant flights is complete. 

Flight-Level Reconciliation 

 The verifier compares the flights within the relevant regulatory scope in the operator’s submitted data against the corresponding flights in the independent third-party dataset. 

 The comparison is normally performed at the flight level using information such as: 

• Flight date and time; 
• Flight number; 
• Departure and arrival airport; 
• Aircraft registration; 
• Operator information; 
• Other available flight identifiers. 

The verifier looks for differences in both directions: 

Third-party source → Operator data 

Are there flights in the independent source that are missing from the operator’s reported population? 

Operator data → Third-party source 

Are there flights in the operator’s data that cannot be identified in the independent source? 

Both types of differences require investigation. The absence of a flight from the third-party dataset does not automatically mean that the operator’s data are incorrect, just as the presence of a flight in the third-party dataset does not automatically mean that it should have been reported. 

This comparison forms part of the completeness assessment, which is performed for each dataset provided by the aircraft operator. The assessment is an iterative process and may continue throughout the verification activities as additional information, supporting evidence, or discrepancies are identified and addressed.  

The objective is to ensure that, by completion of the verification activities, the final dataset used for reporting is complete and appropriately reflects the applicable regulatory scope, with sufficient and appropriate evidence to obtain reasonable assurance that all flights required to be included under the applicable regulatory requirements have been identified and included in the reported flight dataset. 

Verification of Flight Exemptions 

Flight completeness can also help assess whether flights excluded from the reporting population have been correctly treated as exempt or outside the applicable scope. 

EUROCONTROL data can provide useful information on exemptions through different third-party data sources, including Pro Forma Route Charge invoices, EUROCONTROL ETS Support Facility data, and SB/SM data. These sources may contain exemption codes or indicators, with each code corresponding to a defined exemption category and meaning. The verifier can therefore compare the exemption code identified in the operator’s data against the corresponding code and its defined meaning in the relevant EUROCONTROL source to assess whether the flight has been correctly classified.

Where the operator’s data identifies a flight as exempt, but the available EUROCONTROL source does not support the same classification, the verifier requests the ATC flight plan from the operator to obtain additional evidence supporting the exemption. 

The primary supporting evidence shall be the ATC flight plan filed for the flight as required by the various regulations, particularly where the exemption depends on the purpose or operational characteristics of the flight. 

The verifier assesses whether the evidence demonstrates that the applicable exemption criteria were actually met. An exemption classification within the operator’s database is therefore not, by itself, sufficient; the classification needs to be supported by appropriate evidence where required. 

Conclusion 

The Flight Completeness Check is a critical first step in the verification of aviation environmental data. By comparing the operator’s reported flight population with an independent third-party source, the verifier can identify potentially missing, duplicated, incorrectly classified or incorrectly exempted flights before proceeding to the detailed assessment of fuel and emissions data.

Importantly, discrepancies are not automatically treated as errors and the operator is often contacted for clarifications and investigations. The verifier assesses the underlying operational circumstances, including diversions, revised flight plans, duplicate records and other legitimate differences. Where an exemption or discrepancy cannot be supported by the available data, the matter is raised with the operator for further evidence and resolution.

Ultimately, the purpose of the completeness check is to provide confidence that the flights reported by the operator represent the relevant flights actually operated and that any exclusions or exemptions are appropriately justified. A robust, independent and evidence-based completeness assessment therefore provides the foundation for reliable verification across the different aviation environmental schemes.