1. For the purposes of proceedings under article 81 and this article, the Appeals Chamber shall have all the powers of the Trial Chamber.
Proceedings on appeal
2. If the Appeals Chamber finds that the proceedings appealed from were unfair in a way that affected the reliability of the decision or sentence, or that the decision or sentence appealed from was materially affected by error of fact or law or procedural error, it may:
For these purposes, the Appeals Chamber may remand a factual issue to the original Trial Chamber for it to determine the issue and to report back accordingly, or may itself call evidence to determine the issue. When the decision or sentence has been appealed only by the person convicted, or the Prosecutor on that person's behalf, it cannot be amended to his or her detriment.
3. If in an appeal against sentence the Appeals Chamber finds that the sentence is disproportionate to the crime, it may vary the sentence in accordance with Part 7.
4. The judgement of the Appeals Chamber shall be taken by a majority of the judges and shall be delivered in open court. The judgement shall state the reasons on which it is based. When there is no unanimity, the judgement of the Appeals Chamber shall contain the views of the majority and the minority, but a judge may deliver a separate or dissenting opinion on a question of law.
5. The Appeals Chamber may deliver its judgement in the absence of the person acquitted or convicted.