54. Persons authorised to certify- The certification required under Parts VI, XIIB, and XIIIA of these rules shall be signed by appropriately licensed engineers or authorised persons qualified under the terms and conditions of the licence, authorisation or approval, as the case may be, to carry out or inspect the manufacture, process, modification, repair, replacement, overhaul or maintenance, to which the certificate relates or by an approved person or by a person or persons holding written authorisation for certification from an approved organization in accordance with the criterion specified by the Director-General and the certificate is signed as per the authorisation, or when these have been carried out at a suitably equipped Indian Air Force Establishment, by its Officer-In-Charge :

Provided that in one or more class of aircraft, such of the work, if performed in accordance with approved procedures, practices and methods as may be specified by the Director-General, need not be supervised or certified by the approved organisation, licensed engineers or authorised persons in this behalf.