[6] During the first four months of the War in Donbas in 2014, Ukraine suffered considerable losses, including four Mi-24 gunships and two Mi-8 helicopter transports.[7] Due the widespread availability of surface-to-air missiles amongst the separatist militias, the UAA was forced to restrict the use of its assets.[8] While most of the Army Aviation fleet was old, the salaries were poor, and pilots received very few annual training hours (fewer than 44 hours in 2019, and only 50 in 2020), their combat experience during the War in Donbas and peacekeeping operations in Africa as part of United Nations missions in Liberia and the Democratic Republic of Congo (DRC), along with the fact that several Ukrainian pilots and ground crews served as private military contractors in Chad, Ivory Coast, and Equatorial Guinea, made the UAA as one of the most battle-hardened elements of the Ukrainian Armed Forces prior to the Russian invasion of Ukraine in 2022.[9] During the invasion, the UAA Mi-24s conducted ground attacks against advancing Russian columns,[10] while Mi-8s (supported by Su-24MRs or Mi-24s) took part during the siege of Mariupol, ferrying reinforcements and supplies for the beleaguered defenders and evacuating wounded personnel, until an increase in Russian air defenses made further resupply missions too dangerous.Overall, the UAA made 18 successful flights to Mariupol, delivering 30 tons of cargo, 72 soldiers, while evacuating 64 wounded.