Pakistan reported that it had lost 31 combat aircraft in the last four years, all to accidents during training flights. This is a loss of about 2.2 percent (of all combat aircraft) a year. Only seven pilots were lost. The aircraft loss rate is more than twice what it is in  Western air forces. The main reason is the older, and Russian designed, aircraft. These warplanes were designed to be used little in peacetime, and to last long enough to useful, and not much longer, in combat. But the Pakistanis train their pilots to Western standards, meaning 200 or so hours a year in the air. The Russian designed (and often Chinese made) aircraft were not built for that kind of use. India has had the same problem with its Russian designed MiG-21s. The Russian Cold War era designs were cheaper to build and maintain, but were less effective than the Western designs (which were more than three times as expensive, more capable in combat and much more reliable.) By the end of the Cold War, Russian warplane design was switching to the Western model. But many countries, like Pakistan, China and India, still have many of those older Russian designs.