Section 15(1) in The Indian Foreign Service Branch 'B' Rules, 2017
(1)Regular vacancies in the Principal Staff Officer Grade shall be filled as per the guidelines issued for Non-Functional Selection Grade applicable in case of organised Group `A' Services with officers of the Senior Principal Private Secretary Grade who have on the crucial date rendered not less than five years of approved service in that Grade failing which by promotion of Senior Principal Private Secretary with 10 years combined regular service in the Grade of Senior Principal Private Secretary and Principal Private Secretary out of which minimum three years shall be in the Grade of Senior Principal Private Secretary.
