28 U.S.C. § 1292 : US Code - Section 1292: Interlocutory decisions

      (a) Except as provided in subsections (c) and (d) of this
    section, the courts of appeals shall have jurisdiction of appeals
    from:
        (1) Interlocutory orders of the district courts of the United
      States, the United States District Court for the District of the
      Canal Zone, the District Court of Guam, and the District Court of
      the Virgin Islands, or of the judges thereof, granting,
      continuing, modifying, refusing or dissolving injunctions, or
      refusing to dissolve or modify injunctions, except where a direct
      review may be had in the Supreme Court;
        (2) Interlocutory orders appointing receivers, or refusing
      orders to wind up receiverships or to take steps to accomplish
      the purposes thereof, such as directing sales or other disposals
      of property;
        (3) Interlocutory decrees of such district courts or the judges
      thereof determining the rights and liabilities of the parties to
      admiralty cases in which appeals from final decrees are allowed.

      (b) When a district judge, in making in a civil action an order
    not otherwise appealable under this section, shall be of the
    opinion that such order involves a controlling question of law as
    to which there is substantial ground for difference of opinion and
    that an immediate appeal from the order may materially advance the
    ultimate termination of the litigation, he shall so state in
    writing in such order. The Court of Appeals which would have
    jurisdiction of an appeal of such action may thereupon, in its
    discretion, permit an appeal to be taken from such order, if
    application is made to it within ten days after the entry of the
    order: Provided, however, That application for an appeal hereunder
    shall not stay proceedings in the district court unless the
    district judge or the Court of Appeals or a judge thereof shall so
    order.
      (c) The United States Court of Appeals for the Federal Circuit
    shall have exclusive jurisdiction - 
        (1) of an appeal from an interlocutory order or decree
      described in subsection (a) or (b) of this section in any case
      over which the court would have jurisdiction of an appeal under
      section 1295 of this title; and
        (2) of an appeal from a judgment in a civil action for patent
      infringement which would otherwise be appealable to the United
      States Court of Appeals for the Federal Circuit and is final
      except for an accounting.

      (d)(1) When the chief judge of the Court of International Trade
    issues an order under the provisions of section 256(b) of this
    title, or when any judge of the Court of International Trade, in
    issuing any other interlocutory order, includes in the order a
    statement that a controlling question of law is involved with
    respect to which there is a substantial ground for difference of
    opinion and that an immediate appeal from that order may materially
    advance the ultimate termination of the litigation, the United
    States Court of Appeals for the Federal Circuit may, in its
    discretion, permit an appeal to be taken from such order, if
    application is made to that Court within ten days after the entry
    of such order.
      (2) When the chief judge of the United States Court of Federal
    Claims issues an order under section 798(b) of this title, or when
    any judge of the United States Court of Federal Claims, in issuing
    an interlocutory order, includes in the order a statement that a
    controlling question of law is involved with respect to which there
    is a substantial ground for difference of opinion and that an
    immediate appeal from that order may materially advance the
    ultimate termination of the litigation, the United States Court of
    Appeals for the Federal Circuit may, in its discretion, permit an
    appeal to be taken from such order, if application is made to that
    Court within ten days after the entry of such order.
      (3) Neither the application for nor the granting of an appeal
    under this subsection shall stay proceedings in the Court of
    International Trade or in the Court of Federal Claims, as the case
    may be, unless a stay is ordered by a judge of the Court of
    International Trade or of the Court of Federal Claims or by the
    United States Court of Appeals for the Federal Circuit or a judge
    of that court.
      (4)(A) The United States Court of Appeals for the Federal Circuit
    shall have exclusive jurisdiction of an appeal from an
    interlocutory order of a district court of the United States, the
    District Court of Guam, the District Court of the Virgin Islands,
    or the District Court for the Northern Mariana Islands, granting or
    denying, in whole or in part, a motion to transfer an action to the
    United States Court of Federal Claims under section 1631 of this
    title.
      (B) When a motion to transfer an action to the Court of Federal
    Claims is filed in a district court, no further proceedings shall
    be taken in the district court until 60 days after the court has
    ruled upon the motion. If an appeal is taken from the district
    court's grant or denial of the motion, proceedings shall be further
    stayed until the appeal has been decided by the Court of Appeals
    for the Federal Circuit. The stay of proceedings in the district
    court shall not bar the granting of preliminary or injunctive
    relief, where appropriate and where expedition is reasonably
    necessary. However, during the period in which proceedings are
    stayed as provided in this subparagraph, no transfer to the Court
    of Federal Claims pursuant to the motion shall be carried out.
      (e) The Supreme Court may prescribe rules, in accordance with
    section 2072 of this title, to provide for an appeal of an
    interlocutory decision to the courts of appeals that is not
    otherwise provided for under subsection (a), (b), (c), or (d).