Under the Federal Rules of Appellate Procedure, the deadline for requesting an en banc rehearing is 14 days after the panel’s entry of the order which was 24 June. So a request for an en banc hearing could come from Flynn or the COA on its own motion on or before 8 July- next Wednesday. At that point the mandamus order is final.
Circuit Rule 35Petition for Panel Rehearing and Petition for Hearing or Rehearing En Banc
(a) Time Within Which to File. In all cases in which a party is one of those listed in FRAP 40(a)(1)(A) - (D) [government], the time within which any party may seek panel rehearing or rehearing en banc is 45 days after entry of judgment or other form of decision. In all other cases, any petition for panel rehearing or petition for rehearing en banc must be filed within 30 days after entry of judgment or other form of decision. The time for filing a petition for panel rehearing or rehearing en banc will not be extended except for good cause shown.
The 21 day "deadline" appears to control this case because that is when the order from the Circuit Court becomes effective. If the order is put into effect, the Flynn case becomes closed.
Circuit Rule 41Issuance of Mandate; Stay of Mandate; Remand
(3) Writs. No mandate will issue in connection with an order granting or denying a writ of mandamus or other special writ, but the order or judgment granting or denying the relief sought will become effective automatically 21 days after issuance in the absence of an order or other special direction of this court to the contrary.
Rule 40 has a 14 day deadline to petition for a panel rehearing