As Nudelhirsch pointed out, even some modern Russian aircraft have several crew stations more than on other aircraft. On some flights, the An-124 and 225 can carry a complement of 18 crew, 6 of which are responsible for flying the thing, while the other 11 + loadmaster are specialists in various aircraft systems and are equipped to fix basically any part of the plane that does not require big, highly-specialized tools.
While GPS has facilitated navigation a lot, it is still not very widespread in northern regions, Siberia to name one. Along with the lack of ground aids in the form of radio-nav stations, careful navigation is essential and to minimize errors, much as you would cross-check INS systems in old jetliners, two navigators are used on each flight. In this form, the essential flight crew on the big Antonovs is:
- communications officer
- two navigators
No plane, no gain.