Federal Rule of Civil Procedure 39
Rule 39. Trial by Jury or by the Court
(1) the parties or their attorneys file a stipulation to a nonjury trial or so stipulate on the record; or
(2) the court, on motion or on its own, finds that on some or all of those issues there is no federal right to a jury trial.
(b) WHEN NO DEMAND IS MADE. Issues on which a jury trial is not properly demanded are to be tried by the court. But the court may, on motion, order a jury trial on any issue for which a jury might have been demanded.
(c) ADVISORY JURY; JURY TRIAL BY CONSENT. In an action not triable of right by a jury, the court, on motion or on its own:
(1) may try any issue with an advisory jury; or
(2) may, with the parties’ consent, try any issue by a jury whose verdict has the same effect as if a jury trial had been a matter of right, unless the action is against the United States and a federal statute provides for a nonjury trial.