Section 289(12)(b) in The Naval Ceremonial, Conditions Of Service And Miscellaneous Regulations, 1964
(b)In the case of Engineering Branch candidates :(i)They must have passed the Preliminary Examination for Upper Yardmen (E);(ii)Engine Room/Aircraft/Aircraft (Weapon) /Ordnance /Shipwright Artificers must have held the [Rank] [Substitued by S.R.O. 192, dated 10th September, 1973] of Artificer 4th Class (acting and confirmed) for 18 months, and must not be older than 26 years on the 30th June of the year in which the Preliminary Selection Board is held;(iii)Mechanicians and Aircraft Mechanicians must have served at least 18 months after successfully completing the Mechanician's course, and must not be older than 29 years on the 30th June of the year in which the Preliminary Selection Board is held.