Section 251 in The Naval Ceremonial, Conditions Of Service And Miscellaneous Regulations, 1964
251. Relative Seniority.
(1)The relative seniority of officers of the Indian Navy, Army and Indian Air Force, holding equivalent ranks, who serve together in an Inter-Service Organisation shall be determined as follows:(a)Officers holding equivalent substantive rank (and no acting rank) shall rank according to their seniority in the substantive rank, and(b)Officers holding acting rank shall rank after officers holding corresponding substantive rank. Officers of equivalent acting ranks in relation to each other shall rank according to their seniority in the substantive rank.(2)Joint Service with Land or Air Forces. - When officers of the Navy are employed on shore, on joint service with the land or air forces, their relative rank shall carry with it all the precedence and advantages, except command, attaching to the rank with which it corresponds, and shall regulate the choice of quarters.
