(c)in the case of an aircraft imported by air, a certificate signed by [the Assistant Commissioner of Customs ] [Substituted by G.S.R. 813(E), dated 21.11.2008 (w.e.f. 21.11.2008). ]or any officer above the rank of Assistant Commissioner of Customs duty leviable in respect of it has been paid and stating the type and manufacturer's number of the aircraft and engine, and if the aircraft has been registered elsewhere, its registration markings.