Section 2(4) defines adjudicating authority to mean any authority appointed or
authorized to pass any order or decision under this Act. However, following are not covered under the ambit of adjudicating authority:
(a) Central Board of Customs and Excise (Board),
(b) Revisional Authority,
(c) Authority for Advance Ruling,
(d) Appellate Authority for Advance Ruling,
(e) the Appellate Authority
(f) Appellate Tribunal
Therefore, an order passed by any officer other than the revisionary authority as well as other authorities mentioned above could be contested before the Appellate Authority.
(ICAI FAQ PUBLICATIONS 06-09-2017 APPEALS AND REVISIONS : FAQ NO. 2)