Wojskowe Zakłady Lotnicze Nr 1 (Military Aviation Works No. 1), with its head office in Łódź and branch in Dęblin, is a leader of aviation domain and one of the key companies of Polska Grupa Zbrojeniowa. For over 75 years the company has been strictly connected with aviation industry and for 60 years it has been specializing in helicopters maintenance and overhaul. WZL1 performs services for the Polish Armed Forces and domestic and foreign business partners. Its key activities cover: repair, maintenance and modernization of Mi family helicopters, TW3–117 family engines and services of military and civil aircraft. WZL1 has also been designated as an Center of Operation Sustainment (Service Center) for AW101 Merlin helicopters for the Polish Armed Forces.