To empanel is to select a group of people for a jury. If you’re empaneled, you’re part of a jury. Congratulations. Jury duty is one of those things all adults have to do as members of a democracy — show up in court to possibly be a member of a jury in a trial. When you’re added to a jury, you’re empaneled.
Empanel - Definition, Meaning & Synonyms | Vocabulary.com
www.vocabulary.com/dictionary/empanel
Variant
a way of writing a word which is used by some people as an alternative to the standard or generally accepted form
Seeing as how this is a federal case we should go by the spelling in federal code spelling of impanel.