Gen. Augusto Pinochet filed an appeal today against a British magistrate's ruling that he can be extradited to Spain to be tried on human rights charges. In the meantime, diplomats from Chile, Britain and Spain continued exchanges that could lead to freedom for the former Chilean president.

Pinochet's appeal of the extradition ruling allows him to buy time while politicians and diplomats confer on his status. While the appeal is pending--which could last a year--he will remain under arrest in a rented house outside London.

Pinochet, who ruled Chile with an iron hand for 17 years, was arrested here 53 weeks ago on a warrant from Spain, where a prosecutor has charged him with torture and conspiracy to torture thousands of his political adversaries following the military coup he led in 1973. He has challenged Spain's legal right to charge him and Britain's right to hold him, and has fought the case twice up to Britain's highest court.

Pinochet lost that legal battle in March, when Britain's Law Lords ruled that a former head of state accused of violating international human rights treaties can be brought to trial in almost any country. That principle of "universal jurisdiction" has been described as a key precedent in the emerging field of human rights law.

Pinochet's fate now probably rests with diplomats and doctors. Approaching his 84th birthday, he says he is suffering from various ailments and could not survive a trial. Accordingly, the Chilean government is pushing hard to persuade Britain and Spain to free him on humanitarian grounds.