The Bulgarian Border Police is among the latest frontier guard services in Europe to develop its own aviation unit. Specialised in patrolling and surveillance, the Sofia-based air unit currently operates modern law enforcement technologies to protect the increasingly problematic southern external borders of the European Union.

The Specialised Air Surveillance Unit (SASU) of the Bulgarian Ministry of Interior’s Border Police Chief Directorate is an airborne law enforcement operations unit established in April 2009. Its main base is located at Sofia Airport – North Area and the unit’s principal mission is to provide support to the ground and sea patrol forces employed in securing the Bulgarian borders with neighbouring non-European Union (EU) states.

Known as the so-called ‘Schengen borders’, it is also referred to as external EU borders, this category includes the country’s borders with Turkey, Serbia and North Macedonia. Another patrol areas for the SASU are the country’s Black Sea coastline and Danube River.

Fleet and technologies

The SASU fleet includes a trio of fully-equipped Leonardo AW109 Power light twin-engine helicopters, delivered between March and December 2010, in addition to a single AW139 medium twin, taken on strength in November that year. Three of these helicopters (the AW139 and two AW109Es) were procured by the Bulgarian government under the EU-funded so-called ‘Schengen Facility’ Aid Programme. They feature nearly identical mission equipment installations based on the FLIR Systems Star SAFIRE HD day/night sensor payload for around  the clock border surveillance and patrolling. These machines were originally procured by the Bulgarian Ministry of Finance on behalf of the country’s Ministry of Interior utilising European Union (EU) financial aid representing 75% of the cost while the Bulgarian government provided the rest. According to official information released by the Bulgarian government, the total price of these three helicopters exceeded Euro 29 million.

The third AW109E that initially lacked role equipment, was purchased with national funds. In 2019, it was finally outfitted with a full mission suite, based on the much more advanced FLIR Systems Star SAFIRE 380HD.   

Despite their sophisticated mission suites, both the 3t-class AW109 and 6.4t-class AW139 have proved to be easy to support and to date, have demonstrated good reliability. 


In mid-2015, SASU moved to a brand-new base complex, comprising of a large-size helipad, spacious maintenance hangar and administrative building at Sofia Airport – North Area. This is the unit’s main operating base, constructed thanks to the generous EU funding assistance granted to Bulgaria under the so-called External Borders Fund facility. The Sofia-based SASU helicopters are mainly responsible for air patrolling alongside the Serbian and North Macedonia borders (and are called upon to reinforce the Turkish border patrolling operation on as-needed basis) in addition to being tasked with a host of other law enforcement and general support missions.

Bezmer airfield in the south-eastern part of the country is the second permanent SASU base, which responsible for the border patrol operations alongside the problematic Turkish border and the Black Sea coastline.  The SASU commenced regular flight training operations in January 2011 with a pair of its band-new helicopters then being urgently deployed the following month to Bezmer, an active military airfield situated not far from the border with Turkey. At Bezmer, the flight crews start their initial in-country flight training, with the first operational border patrol missions reported during March 2011. Bezmer was declared a permanent SASU base in 2012.

NVG Operations

With the backbone of the unit formed in 2010-2011, it has seen little change since with most of the SASU pilots and technicians being ex-military personnel. The unit has matured to 24-hour border patrol capability following, in late 2015, the unit completing Night Vision Google (NVG) training courses for its most experienced aircrews. The training was undertaken by an instructor pilot from the German Federal Police, while there were also pilots with NVG experience gained during their service with the Bulgarian Air Force. Later, these local pilots became instructors to train the rest of the crews in NVG operations. The unit aircrews use exclusively the Bulgarian-made Optix Diana-A aviator NVG sets.

The SASU helicopters carry military-style serial numbers and its pilots and technicians hold military- licenses. All flying is undertaken under national military rules while the airworthiness of the fleet is supervised by the Bulgarian MoD’s military aviation authorities.

Border patrolling

SASU’s concept of border patrol operations were strongly influenced by the German Federal Police expertise and experience, and includes three main types of operational missions. The first of them calls for an urgent response, prompted by a developing emergency situation at the border and using a helicopter on quick reaction alert (QRA) at a forward operating location. The machine is scrambled to provide air support to the surface patrol forces engaged in hot pursuit of illegal migrants or smugglers after they cross the border. The second one represents a routine scheduled border patrol mission while the third includes undertaking reinforced surveillance operations within a pre-designated border sector, looking for signs of illegal activity such as border crossings of immigrants or smuggling of goods.   

Bulgaria has been an EU member state since 1 January 2007 and was originally slated to join the Schengen zone (where the citizens of 26 European countries are free to travel in and out of this zone as one single country sharing equal international travel rights) as a full-right member in 2011. Its acceptance, however, was indefinitely postponed and as of December 2022 there were still issues but there are hopes that entry into the Schengen zone will happen at last in 2023.

Regardless, it borders non-EU states. The Danube River and Black Sea borders are now considered as the outer borders of EU, and the well-kitted SASU helicopters provide high-tech support to the overall border protection effort against the sharply increased illegal migration wave in addition to countering the contraband smuggling of goods and drugs and all other forms of trans-border criminal activity Bulgaria may face as part of the united Europe.

In addition to the SASU core business represented by a variety of border patrol missions, its FLIR-equipped helicopters are seen as high-value assets of the Bulgarian Ministry of the Interior (MoI), useful for enhancing the nation’s overall law enforcement capabilities. Both the AW109 and AW139 have conducted various law enforcement operational missions on an on-demand basis day and night, on behalf of other MoI directorates and other ministries and government agencies in Bulgaria.

The most prominent of these non-core missions of the SASU are the wildfire monitoring and mapping as well providing the rapid delivery and other forms of air support of MoI’s Sofia-based specialised counter-terrorist unit dubbed the Red Berets.

The helicopters have also seen active employment in specialised operations against drug producers and smugglers in border areas, detecting fields planted with marijuana in otherwise inaccessible mountainous locations along Bulgaria’s south-western borders.