A deviation in the operation of a system on the F-16 Block 70 fighter has been identified during the aircraft acceptance process, according to the Bulgarian Air Force Commander, Major General Nikolay Rusev. He clarified that the issue was discovered after the aircraft landed in Bulgaria, though it remains uncertain whether the deviation occurred during the flight or after its arrival. Rusev emphasized that the detection of a system deviation does not mean the aircraft is defective.

The acceptance of the aircraft is still ongoing and involves two distinct stages—technical and flight acceptance. Rusev noted that the process is lengthy, and the aircraft will only be officially accepted into service once both stages are successfully completed. As part of the flight acceptance phase, at least two flights must be carried out with a Bulgarian pilot. Only after the pilot confirms the aircraft is airworthy will it be introduced into operational service with the Bulgarian Air Force.

Defense Minister Atanas Zapryanov added that all financial resources for the acquisition of the aircraft have been secured, including funds for infrastructure development at the Third Air Base, which is currently under construction. He also confirmed that negotiations are ongoing with the United States government to ensure the supply of spare parts and support the aircraft's life cycle.

The first Bulgarian F-16 Block 70 was officially welcomed during a ceremony on March 13 at the Third Air Base and landed there on April 2. The aircraft, delivered by Lockheed Martin, is a combat training (two-seater) version. Its operational deployment will follow the completion of technical and flight acceptance procedures. The rest of the aircraft under the initial contract are expected to be delivered in phases through the end of 2025. An additional eight aircraft, part of a second contract, are scheduled to be delivered by 2027, at which point Bulgaria will have one complete F-16 Block 70 squadron.

The aircraft’s status has become the center of political controversy following remarks from GERB leader Boyko Borissov. He accused President Rumen Radev of informing journalists that the F-16 was not operational, prompting Borissov to demand the dismissal of the Air Force Chief if this claim proved true. In response, President Radev refrained from directly confirming the fighter jet’s inability to fly but suggested that the issue reflects broader shortcomings in defense planning and funding.

Former Defense Minister and current Presidential Secretary for Defense Dimitar Stoyanov, who is also an aircraft engineer, confirmed that the aircraft cannot fly due to a technical failure involving a damaged unit. He stated that the necessary spare part is not available in Bulgaria because it was not included in the initial order package. According to Stoyanov, this omission was made to lower the overall cost of the deal.

He explained that such failures are common in newly manufactured aircraft, especially during their initial phase of operation, when the highest number of malfunctions typically occurs. Stoyanov emphasized that the defect needs to be repaired before the aircraft can be flown and that this situation is normal in aviation. However, he criticized the lack of readily available spare parts and blamed former Prime Minister Borisov and then-Defense Minister Karakachanov for approving a reduced package that excluded these parts.

Stoyanov also accused current Defense Minister Atanas Zapryanov, who was involved in the negotiations at the time, of misrepresenting the completeness of the package. He pointed out that the current problem could have been avoided if the offer with guaranteed 24-hour delivery of spare parts had been accepted. Instead, Bulgaria opted for a cheaper deal, which led to longer delivery times and a shortage of critical components.

In addition, Stoyanov denied Zapryanov's claim that a second F-16 is already en route to Bulgaria. He stated unequivocally that no such aircraft has departed and none is expected to arrive in the coming days, contradicting the defense minister’s previous public statements. He also reminded the public that the F-16 will not be flying during the military parade on May 6, despite earlier assurances from Minister Zapryanov.

During an extraordinary briefing, the Ministry of Defense admitted the presence of a technical issue preventing the aircraft from flying. Air Force Commander Rusev reiterated that a deviation had been detected in the operation of one of the systems. Minister Zapryanov again emphasized that funds for infrastructure and operational readiness, including spare parts, had been planned for and are being coordinated with the U.S. government.

The first F-16 Block 70 aircraft remains grounded as the Bulgarian Air Force continues its acceptance procedures and awaits the arrival of necessary spare parts to resolve the technical issue.