(a) General rule. A person must file a petition when seeking:
(2) A declaratory order or rule to terminate a controversy or remove uncertainty;
(3) Action on appeal from a staff action, other than a decision or ruling of a presiding officer, under Rule 1902;
(4) A rule of general applicability; or
(5) Any other action which is in the discretion of the Commission and for which this chapter prescribes no other form of pleading.
(b) Declarations of intent under the Federal Power Act. For purposes of this part, a declaration of intent under section 23(b) of the Federal Power Act is treated as a petition for a declaratory order.