The full reasons for the separation between Russian freight carrier Volga-Dnepr Airlines and the Ukraine’s Antonov Airlines remain unclear almost a week after the former announced it would end their 10-year-old Ruslan International joint venture from Dec. 31, 2016. Through Ruslan, the partners operate specialist charter flights carrying bulky items of cargo in Antonov An-124-100 widebodies, and the arrangement has continued since tensions erupted between the Ukraine and Russia over the latter’s annexation of the Crimea region in 2014.

According to Dennis Gliznoutsa, Volga-Dnepr’s vice president for development and special projects, the separation will leave the Ulyanovsk-based company “free to take commercial decisions that are in the best in interests of our group and our customers.” The company will continue to operate a fleet consisting of 12 Ukrainian-built An-124s, as well as five Ilyushin Il-76s and an unspecified number of Boeing 747s and 737s.

According to Volga-Dnepr, Antonov Airlines, which operates as part of the Ukraine’s Antonov design bureau, “will continue to collaborate in regards to the technical aspects of [the] An-124 fleet.” However, the Russian carrier has not explained how it will maintain the An-124s and ensure a supply of spare parts. Volga-Dnepr holds the controlling 51 percent stake in Ruslan.

“We have the advantage of the experience we gained from the end of our An-124 joint venture with HeavyLift Cargo Airlines in 2001, and the subsequent growth of our outsize and heavyweight cargo business in the international market. We emerged from that JV stronger and now, 15 years later, we will do so again,” said Tatyana Arslanova, Volga-Dnepr’s vice president for strategic management and charter cargo operations. “We now have an even more diverse and capable product offering for our customers under our ‘Cargo Supermarket’ concept, which combines our growing An-124, IL-76TD-90VD, Boeing 747 and 737 freighter fleet and logistics services.”