CU Phosco supports award-winning Sofia Airport with high mast retrofit programme

CU Phosco, working in partnership with Bulgarian contractor LOG Siberia, has completed a high mast retrofit scheme at Sofia Airport (SOF Connect). The project involved replacing the raising and lowering systems in 11 existing high masts to restore full functionality, safety, and reliability. This approach extends the life of the airport’s infrastructure, reduces material waste, and minimises disruption to airfield operations. 

Sofia Airport, officially named Vasil Levski Sofia Airport, is Bulgaria’s largest international gateway and a key transport hub for Southeast Europe. Operated by SOF Connect, the airport was recently recognised by ACI EUROPE as Best Airport in Europe (5–10 million passengers), celebrating its ongoing transformation and sustainable development.

The retrofit programme focused on the main aircraft apron serving Terminal 2, where a series of high masts provide essential lighting for aircraft stands, taxiways, and ground operations. Over time, several of these masts had developed faults in their raising and lowering systems, affecting maintenance access and operational efficiency.

To maintain safety and ensure reliable illumination across the airfield, SOF Connect decided to refurbish the existing masts rather than replace them entirely, a sustainable approach that reduces material waste and preserves the airport’s operational infrastructure.

CU Phosco was appointed by specialist contractor LOG Siberia to design, supply, and supervise the installation of new raising and lowering systems, ensuring compatibility with the existing mast structures and compliance with relevant safety standards.

The project centred on the replacement of the existing raising and lowering mechanisms within 11 high masts, restoring safe ground-level access for maintenance without the need for elevated working platforms or extended airside closures.

The retrofit approach enabled Sofia Airport to modernise critical infrastructure while maintaining continuity of operations in a live airfield environment. CU Phosco provided technical expertise throughout the project, working closely with the local contractor to ensure correct installation, system integrity, and long-term reliability.

Lee Sanderson, Export Manager at CU Phosco, describes: “CU Phosco supplied 11 sets of raising and lowering retrofit kits, comprising of winch, rigging, head frame and lantern carriage. We assisted the local contractor to put the existing high masts back into operation for maintenance at ground level using the CU Phosco In-Tension system. This is the first stage of a programme to retrofit all 36 masts airside at the airport.”

The retrofit programme has reinstated full raising and lowering capability across the airport’s high mast network, ensuring safe and efficient maintenance operations for years to come.

The project demonstrates the value of proactive maintenance and refurbishment in extending asset life and improving sustainability, particularly in safety-critical environments such as airports.

A representative at SOF CONNECT AD commented: “SOF CONNECT AD, the concessionaire of Sofia International Airport ‘Vasil Levski’, is undertaking a programme of airport modernisation with a strong focus on improving the functionality, reliability and energy performance of the apron lighting system.

As part of this programme, retrofit works were carried out on 11 existing steel tubular high masts located within aircraft parking, approach and taxiway areas, involving the replacement of the raising and lowering system components.

The works were delivered during the normal operation of the airport, with all necessary safety precautions in place, and without disruption to airport operations or passenger services. The retrofit was completed under the supervision of the manufacturer’s specialist and in accordance with approved installation procedures.

This approach has enabled the continued use of existing infrastructure while improving reliability and supporting our long-term operational and maintenance objectives.”