THE People's Liberation Army (PLA) is testing its newly acquired fleet of Russian-made jet fighters, the Su-27s, at an air base near the border between Anhui and Jiangsu provinces. Military analysts said Beijing had only acquired 24 of the state-of-the-art aircraft and was likely to try to buy additional ones from Moscow. ''Twenty-four is a small number and does not provide for economies of scale in areas like maintenance and servicing,'' a military analyst said. ''Moreover, for logistics reasons, only around 70 per cent of a fleet could be deployed in times of war.'' It is understood that Russian military and aviation experts are helping to train the Chinese pilots and technicians who will operate the Su-27s. ''Ideally, the Chinese would like to acquire the technology from the Russians to manufacture the Su-27s,'' another source said. ''However, since Moscow is desperate for hard currency, it is unlikely to agree to Chinese production under Russian licensing.'' The Chinese have also discussed the purchase of other Russian-made fighters, including MiG-29s. Western diplomats in Beijing said the PLA was eager to hire the large number of Russian military and weapons experts laid off in the wake of the massive cutback in Moscow's defence capacities. However, the Russian Government is known to have prevented some of its military experts from leaving for countries including China and North Korea. The diplomats said Sino-Russian talks on a wide range of military co-operation, including the exchange of technology, were taking place on a ''continuous basis''. Meanwhile, the New China News Agency has reported that the Central Military Commission, China's highest military council, has issued a legislative package for the Eighth Five-Year Plan period (1991-1995), to ''further stress and improve the legal construction of the armed forces''. It was the first time the commission had issued such a comprehensive plan. Military analysts said the laws would legitimise the special status of the PLA in national life, including the devotion of a large chunk of national resources to ''military modernisation''.