KEA
With respect to 2024, the value of the indicator has been improving in terms of both the KEA (from 3.52% in 2024 to 3.38% in 2025) and the KEA corrected to take into consideration the effect of the conflict in Ukraine (from 2.18% to 2.10%). In terms of “ranking” those values place Bulgaria in 19th and 15th place among the States.
In terms of additional distance, the average per flight is 0.84km of internal additional distance out of 9.41km additional distance. This suggests the presence of “straight” internal portions which are not well aligned with the entire trajectories.
The additional distance for Bulgaria corresponds to 4.01% of the additional distance in the SES area (21st contribution). This value has been increasing from 3.79% in 2023 and 3.98% in 2024.
Regarding the assessment of the achieved level of actual performance in the environment KPA, the NSA reports: “The negative trend in KEA performance was registered at the end of 2015 and beginning of 2016. It was thoroughly analysed using detailed data, provided by the PRU. An analysis report outlines the major reasons for the deterioration in flight efficiency as a combination of the following:
1. The crisis in Crimea region and subsequent political developments (the Ukrainian ban on Russian Federation aircraft to operate in Ukrainian airspace - enforced on 25 October 2015), preventing traffic from flying optimum routes;
2. Airlines preferences for longer and more inefficient (from HFE methodology perspective) routes due to various reasons and their own assessment on the use/non-use of certain airspaces;
3. It was found out that the change in values was driven by an underlying change in the application of the HFE methodology, stemming from data accuracy and availability. The deterioration was not in anyway related to any change in traffic flow patterns or operational practices but was entirely due to inconsistencies in HFE measurement.
4. Additionally, the war in Ukraine, which began on 24 February 2022, brought about a ban of flights in vast portions of Russian airspace and the complete closure of Ukrainian airspace. This was a major factor which has not existed at the time of the RP3 performance plan preparation and environmental target setting but has had a major impact on the deviations of traffic flows.
These restrictions led to material and continuous traffic flow shifts and traffic increases above the plan, since airspace users are forced to fly far from optimal trajectories. Moreover in order to balance sector loads it became necessary to implement specific traffic flow rules. . Such implemented traffic flow rules should be regarded as capacity enablers by reducing the complexity or workload in particular hot spots and giving the opportunity to accommodate extra traffic that is not in favour of KEA at large.
5. Lack of sufficient capacity in neighbouring ACCs which results in additional traffic through Sofia FIR based on airlines' preferences to choose the next best routes to avoid delays.
In 2023 it was noted that revision of KEA methodology should be carried out so that circumstances beyond the ANSP's control are properly reflected. The shortcomings of the current KEA methodology are largely recognised. All these factors result in higher-than-planned KEA and are due to reasons beyond BULATSA control.”
Regarding the identification and analysis by the NSA of the underlying reasons or circumstances having led to the performance target not being achieved, the NSA reports: “The Analysis is as provided above. It should be noted that all possible measures are taken at local level
(such as the cross-border expansion of FRA airspace over several countries), but their impact on the overall trend remains limited.”
Regarding recommendations to the ANSP to rectify the situation, the NSA reports: “KEA values are to be monitored monthly through the data officially published by PRU. However, given the reasons
described above an improvement of KEA values will hardly materialise under the existing airspace restrictions.”
Regarding remedial measures that have been / will be taken by the ANSP to rectify the situation, the NSA reports: “As explained above.”
KEP
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KES
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Vertical flight efficiency
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