closed . ▁MR - 6 ( Mor sk oj ▁raz vy ed ch ik ▁– ▁mar itime ▁reconna issance ) ▁R - 6 , ▁tor ped o ▁bom ber ▁version , ▁ 1 9 3 2 . ▁P - 6 ( Pa ass az h ir sk ii ▁– ▁passenger ▁transport ) ▁Civil ▁cargo ▁and ▁passenger ▁transport ▁version . ▁R - 6 ▁Lim uz in N ine - se at ▁civil ▁transport ▁version ▁with ▁a ▁closed ▁co ck pit ▁and ▁a ▁seven - se at ▁cabin ▁with ▁glass ▁windows ▁and ▁a ▁lug g age ▁compart ment . ▁Power ed ▁by ▁two ▁ ▁B MW ▁VI ▁V - 1 2 ▁engines . ▁First ▁flow n ▁in ▁July ▁ 1 9 3 3 , ▁the ▁sole ▁R - 6 L ▁crash ed ▁on ▁ 5 ▁September ▁ 1 9 3 3 ▁as ▁a ▁result ▁of ▁a ▁maintenance ▁error . ▁AN T - 1 8 Gr ound ▁attack ▁version ▁with ▁two ▁Mik ul in ▁M - 3 4 , ▁arm or ▁protection , ▁and ▁two ▁d ors ally - mount ed ▁machine ▁guns . ▁ ▁Oper ators ▁Military ▁operators ▁ ▁Soviet ▁Air ▁Force ▁Soviet ▁Naval ▁A viation ▁ ▁Civil ▁operators ▁ ▁Aer of lot ▁A via ▁Ar kt ika ▁ ▁Acc idents ▁and ▁inc idents ▁June ▁ 2 3 , ▁ 1 9 4 1 : ▁A ▁Dal st ro i ▁A viation ▁PS - 7 ▁crash ed ▁on ▁take off ▁from ▁Ch ok urd akh ▁after ▁the ▁left ▁float ▁struck ▁a ▁sub mer ged ▁log