Bulgaria Air Meintenance EAD


Tehnoimporteksport AD


Plan 31 Ltd, Arch. Plamen Tsvetkov


Energoproekt Jsc. and Plan 31 Ltd., Arch, Svetoslava Andreichin



Within the certified investment project: „West Wing Extension Project: Expanding the aircraft repair & maintenance facilities of Lufthansa Technik Sofia Ltd., implemented jointly by Bulgaria Air Maintenance and Lufthasa Technik Ltd, who received the prestigious award “Investor for the Year 2017” namely because of the construction of such a unique facility, Hangar 1 was built, being the largest facility on the territory of Eastern Europe for aircraft service and repair. With the construction of the hangar the possibility of a linear and base service of the largest aircraft in the passenger aviation - Airbus 380 was created for the first time outside the main base of Lufthansa in Germany.. The site is exclusive also for its importance, enabling the opening of new workplaces places, as well as training highly qualified staff, including  other airfields in Europe.

Hangar 1 embodies the innovations in the aerospace industry realized in its design, structure,  performance and technical equipment. Its construction changed also the Sofia Airport appearance, adding its vision to a modern aviation center.

The building completes the Lufthansa Technik Sofia complex and turns it into a key center in Europe for line and base aircraft service - including Wide body type airplanes of the Airbus A330/340 and A380 family.

Hangar 1 is built in a restricted area with special access regime.

The hangar building is one-storey, single volume, without a basement, with steel frame structure , spanning the impressive 91.70 without intermediate support.. In the volume of the hangar, monolithic internal buildings for service, technical premises and offices for the administrative staff are situated. The internal building, located along the western façade of the hangar, is a four-storey building, housing the offices, staff rooms and technical premises. The internal building, located along the eastern façade of the hangar, is a two-storey building, housing the toolcrib and service area to the hangar.

The cornice height of the main building of Hangar 1 is + 27.60 m. The maximum elevation of the service staircase to the roof of the building is + 30.00m and the maximum elevation of the highest point of the hangar building facilities are at + 32.50 = 566.60. Hangar 1 is connected to the technological corridor to the east of the workshops located on the ground floor of the newly built multi-functional administrative building. By the same technological connection hangars 1A, 2 and 3 of the complex and the related workshops can also be accessed ..

The main area of the hangar is designed for aircraft repairing and provides simultaneous operation on three narrow-body aircrafts located between axles 4 and 5 on axis 9 and between axles 13 and 14 or for repairing one wide-body aircraft on axis 9.  Two main cranes are operating in the area between axes 3 and 10-11, covering the western and the midline lines, and between axles 10-11 and 15,  the eastern repair line, as well as two track paths for tails of each of the narrow-body aircrafts on axles C and J . The main crane has triple supports and a lifting capacity of 12 tons and a clearance – to the crane hook =17.00 mThe second crane has the same lifting capacity and a clearance – to the crane hook =14.00 m Specialized installation manholes are  constructed under the flooring along with the corresponding technological terminals for operation in the three positions, as well as on the forth position of the wide-body aircraft.

Along the entire northern facade length of Hangar 1, an eclectically-driven segmented lifting hangar door is mounted, with the option for full or partial opening and entrance of one or three aircrafts individually. The door segments are with an aluminum lifting structure and trenches for stepping and fixing in the hangar pavement. A facility of that type has been delivered and mounted for the first time in Bulgaria,, given the size of the hangar door, as well as the specific requirements for its sustainable weather conditions. The terrain in front of the hangar door is at the same level with the hall flooring, and in the last axis, a drainage steel grid is constructed.

The hangar has large-scale glazed curtain walls along the southern and western facades to provide natural lighting in the repair areas. Natural lighting is complemented by evenly spaced strips of  diffuse lighting along the roof plane. The lighting strips have modules with opening parts to provide the necessary smoke extraction and natural ventilation. The curtain walls of the hangar are openable to allow  natural ventilation of the hangar volume.

The clear area of the main hangar volume is 5 676 sq.m.

The flooring in the main hall of the hangar is designed with a minimum slope of 0.5% from the south to the north to provide natural drainage and connection to the existing terrain on the two hangar facades, ensuring both reliability and safe work.

Located on the western façade, the monolithic building in the hangar volume called 'West Offices' on the ground floor houses the crew office spaces - with direct access from the hangar and a separate connection through a corridor to the other premises inside the building. At the same level are built sanitary facilities and a resting room, as well as a connection through a communication staircase and an elevator to the upper three levels of the same building. Within the building, offices for administrative staff, a meeting room, a bathroom and a kitchen cabinet to the common room are located at each level. On the last level are located the spare office premises and a server room to the whole administrative part, as well as the installation premises for the main switchboard and structures, systems and components. The internal administrative monolithic building - west is serviced at all levels by an elevator suitable for disabled persons. The staircase, located south of the offices in a separate volume, serves all office levels, as well as the free area of the last slab of the inner building - as an auxiliary area to the hangar enclosed by a railing. The same staircase is used to access the hangar roof, to service and revise the facilities there, and to provide fire access to the roof of the building. The clear height of all office and auxiliary premises is 2.80 m, and of the ground floor rooms is 3.50 m. The sanitary facilities have a clear height of 2.60m. The area of the inner monolithic building - "Offices West" is 247.13 sq.m and the total area of all offices is 988.52m2.

All of the partition walls have windows for visual connection of the administrative staff with the hangar operations.

On the eastern façade of the hangar, the monolithic building is constructed on two levels - the "Service Building - East" and on the ground floor is located a toolcrib room, connected to the hangar volume through a counter for handing over and receiving the tools used, as well as with a double-wing door from the south to the connecting area with the transport corridor from the east. At upper level at elevation + 4.80 is located the service area to the hangar, with a double-wing sliding door on the western wall accessible from the lifting device at the ground-level. The connection between the individual levels is provided by an internal staircase with a direct evacuation exit outwards, reaching to the last platform, open to the hangar volume at elevation  + 9,60, enclosed by a guardrail. At the same level are located also two technical premises. The clear height in the toolcrib room and the service area to the hangar is 3.60m. The area of the inner monolithic building - east is 232.75m2 and the total area of all offices is 506.39m2.

Hangar 1 has a steel structure of single-span framework, spanning the impressive 91.70 without intermediate support . The main bearing columns are anchored in the monolithic, R.C. foundations. The structure of “offices-west” serves as support of the first framework. The roof of the building is double-pitched, with a minimum slope of 3%. The roofing is executed according to the layer-by-layer assembly method, from trapezoidal sheet T153, rigid mineral wool 16 cm with a volumetric weight of min. 160 kg/m3 and PVC waterproofing membrane. The drainage is internal, vacuum-type, in neck gutters along the axes 1 and 17, with emergency outlets in the boards on the eastern, western and southern facades of the building. Upper bordered lighting was built in 4 strips above the hangar repair areas, with built-in anti-fume valves.

Hangar 1 flooring is  reinforced concrete with epoxy paint coating - durable and resistant to active substances in the technical and the service rooms, the corridors on the ground floor, the monolithic indoor buildings and the staircases. In the sanitary and wet rooms and rest rooms the flooring is made of anti-slip terracotta - plates 20 / 20cm.. The office premises are covered with carpet flooring to provide the necessary soundproofing and comfortable working environments, in the server rooms, boards and control valves - epoxy paint on ground lightweight concrete leveling the room levels.

Hangar 1 heating is resolved in the most economical and environmentally friendly way - by installing thermal radiators on lines run under the roof of the hangar and powered by gas burners located on the roof. The administrative premises are air-conditioned, with ventilation system provided at of all premises.

The building is accessible by disabled persons both at the entrances of the repair base and at adjacent areas. The elevator is adapted for use by disabled people and provides access from the ground floor to all levels of the administrative building. A toilet for disabled persons is also provided in the administrative part on the ground floor.

The construction of Hangar 1 with a gross floor area of 7393 sq.m and an built-up area of 6189 sq.m is a significant contribution to the progress of the aviation industry in the Republic of Bulgaria and has acknowledged the position of the airbase as a dynamically developing and high-tech center in the region.