335Special powers of appeal courts in appeal involving conviction, sentence, or contempt

1. This section applies to an appeal or application for leave to appeal under subpart 3, 4, or 5.

2. For the purposes of an appeal or application for leave to appeal, an appeal court may, if it thinks it necessary or expedient in the interests of justice,—

3. order any witnesses who would have been compellable witnesses at the trial to attend and be examined before the court, whether or not they were called at the trial:
4. order the examination of those witnesses to be conducted before any Judge of the court or before any officer of the court or other person appointed by the court for the purpose, and allow the admission of any formal statements before the court:
5. receive the evidence, if tendered, of any witness (including the appellant) who is a competent but not compellable witness:
6. order that a question arising on the appeal be referred to a special commissioner appointed by the court if the court thinks the question involves prolonged examination of documents or accounts, or any scientific or local investigation, and cannot conveniently be conducted before the court, and act on the report of the commissioner so far as the court thinks fit to adopt it:
7. order the production of any document, exhibit, or other thing connected with the proceeding if the court considers that its production is necessary:
8. appoint any person with special expert knowledge to act as assessor to the court if the court thinks that special knowledge is required for the proper determination of the case.

9. Subsection (2)(a) to (d) and (f) do not apply if an appeal or application is determined just on the basis of written material before the appeal court.