CHINA could possess an aircraft carrier by the time of the Hongkong handover in 1997 with the aim of consolidating its claims over vast areas of ocean in the region. A Chinese naval delegation to Russia recently is thought to have discussed the purchase of the carrier Novorossiyak, currently awaiting disposal near Vladivostok. They also looked over her sister ship Minsk, and although both were found to be in a poor state of repair, bringing them up to operational effectiveness would not be impossible. Writing in the British newspaper The Observer yesterday, Mr Paul Beaver, of the authoritative Jane's Defence Weekly, said the ''blue water navy'' was aimed at consolidating territorial claims to areas of ocean from the Gulf of Tonkin to the Sea of Japan.It is ringing alarm bells in Tokyo where the Japanese Government is worried that an expanded Chinese navy might interfere with its trade routes in the South China Sea and beyond. There is also concern that it might lead to an escalation of the Spratly Islands dispute. The oil-rich islands are claimed by China and five other nations and have been the subject of three violent military incidents in the past decade. Mr Beaver said the flagship for the naval expansion plan was the development for airborne aviation masterminded in the 1980s by Admiral Liu Huaqing. He took the first steps by selecting officers for training in operating aircraft-carrying ships in 1987.