???? ??? ????????? ??? ??? ??? ???????? ?????, ???, ?? ?????????,????????? ?????? ??? ??????? ??????????? ??? ????? ??? ??????????? ??? -?????? ???????????? ????????? ????? ??? ?????????, ??? ??? ????????Coupled with twin gas tanks and twin batteries (which may very well be arrange to operate both or the two engines), the redundancy of two individu