Regulation 8
If any goods of the following descriptions are imported into any part of the United Kingdom other than the Isle of Man for the purposes hereinafter mentioned—
spare parts or equipment imported solely for the purpose of being incorporated in, or used with, any aircraft which is—
registered outside the United Kingdom,
owned and operated by a person whose principal place of business is outside the United Kingdom, and
used in international air transport services and in compliance with the provisions of Regulation 3 of these Regulations;
aircraft, special tools, spare parts and equipment imported solely for the purpose of being used in the search for, or in the rescue, examination, repair or salvage of, an aircraft which is of the kind referred to in paragraph (a) of this Regulation and which has been accidentally lost or damaged;
and if the importer satisfies the Commissioners that the goods will be re-exported as soon as the purpose for which they were imported has been served or before the expiration of such period as may be allowed by the Commissioners, whichever is the earlier, and that the provisions of this Part of these Regulations and such other conditions as may be imposed by the Commissioners are and will be complied with, the goods may be delivered without payment of duty, and duty shall not be payable so long as the Commissioners continue to be so satisfied.