Anecdotally, Russian aircraft are difficult to maintain,particularly older types. Some idea of the challenges the IAF faces can begleaned from the tenders it regularly issues for spares.
The An-32 seems to be a particular culprit. At present there are four separate tenders fordozens of spare parts. These range from32 chains (part # 1-2-02(OST1-10806-72)) to 28 bridges (320207605100-0) and 112 lugs (32.02.9605.261.00).
A number of tenders relate to the IL-76transport and its IL-78 tanker variant. At present the IAF needs 35 wheel hubs(KT-199-100) for its IL-78 fleet. Indian defence pundits have told me that theIAF is rather displeased with its IL-78 fleet, hence its interest in tankersfrom Airbus.
The IAF also needs some serious tyres for its MiG-21s: 1,400tyre nose wheels without tube (500X180), 220 tube nose wheels (500X180A), and 400tyre main wheel with tubes. Tyres willnever be the coolest part of a fighter, but they are important.
All air forces (and vintage car owners, for that matter)face issues finding spares for older equipment.