What are the grounds for appeal against a decision by a judge at the Court of Appeal to overturn a support order?

Before addressing the alleged errors, I emphasize that an appeal court will not overturn a support order unless the reasons disclose an error in principle, a serious misapprehension of the evidence, or a material error: Hickey v. Hickey, 1999 CanLII 691 (SCC), [1999] 2 S.C.R. 518 at para. 11. The rationale for this deference is set out at para. 12: 12 There are strong reasons for the significant deference that must be given to trial judges in relation to support orders. This standard of appellate review recognizes that the discretion involved in making a support order is best exercised by the judge who has heard the parties directly. It avoids giving parties an incentive to appeal judgments and incur added expenses in the hope that the appeal court will have a different appreciation of the relevant factors and evidence. This approach promotes finality in family law litigation and recognizes the importance of the appreciation of the facts by the trial judge. Though an appeal court must intervene when there is a material error, a serious misapprehension of the evidence, or an error in law, it is not entitled to overturn a support order simply because it would have made a different decision or balanced the factors differently.

The purpose of a spousal support order, and any subsequent variation, is to fairly and equitably share the economic consequences resulting from the marriage and its breakdown: Moge v. Moge, 1992 CanLII 25 (SCC), [1992] 3 S.C.R. 813 at 864-866.