21.A.303 Compliance with applicable requirements
The showing of compliance of parts and appliances to be installed in a type-certificated product shall be made:
(a) in conjunction with the type-certification procedures of Subpart B, D or E for the product in which it is to be installed; or
(b) where applicable, under the UKTSO authorisation procedures of Subpart O; or
(c) in the case of standard parts, in accordance with officially recognised Standards.