Since the creation of Pakistan, 14 army chiefs have headed the powerful institution yet only three have successfully completed their tenure of service. According to data colected over time, of the 14 army chiefs, only four were appointed on the basis of seniority. Seven army chiefs got extensions in service either by removing the civilian governments and occupying a position of power or through other means. President Ayub Khan, after becoming Field Marshal remained chief of army staff from January 1951 to October, 1958. General Musa Khan was Commander in Chief from October, 1958 to September, 1966 and General Agha Muhammad Yahya Khan occupied this post from September 1966 to December, 1971. The minimum tenure as C-in-C was that of General Gul Hassan who was the acting C-in-C between 20th December, 1971 and 21 January, 1971 and regular C-in-C up to 2nd March, 1972. He was removed by former President Zulfikar Ali Bhutto under the claim that he was trying to dislodge the elected government. General Tikka Khan headed the army from March, 1972 to March, 1976. After him, General Muhammad Zia-ul-Haq remained army chief from March, 1976 to 17th August, 1988 when his plane crashed near Bahawalpur. General Mirza Aslam Beg was COAS from August, 1988 to August, 1991. General Asif Nawaz Janjua was appointed army chief in August, 1991 and he died on 12th January 1993. General Abdul Waheed headed the army from January, 1993 to January 1996. General Jehangir Karamat was army chief from January, 1996 to October, 1998 and he resigned prematurely. General Pervez Musharraf was made COAS from 7th October, 1998 and he relinquished the charge on 28th November, 2007, after heading the institution for nine years. General Ashfaq Parvez Kayani took over in November, 2007 and after expiry of his tenure and three years extension, he is due to retire by the end of this year
