What is the test for determining whether a trial judge's findings and conclusions of fact have been shown to be wrong?

So a Court of Appeal must decide whether the trial judge's findings and conclusions of fact have been shown to be wrong in a way which either must have altered the result or may well have altered the result. Surely what is meant by the descriptive adjectives "palpable" and "manifest" must be that the error can be identified and can be shown to be an error. The importance of identifying the error is stressed in Beaudoin-Daigneault v. Richard, 1984 CanLII 15 (SCC), [1984] 1 S.C.R. 2 at p. 9. Surely, also, what is meant by the adjective "over-riding" must be that the error is one which either must have altered the result or which may well have altered the result.

If the question is one of mixed fact and law, including the question of whether conduct was negligent, involving, as it does, the application of a legal standard to a set of facts, the task before a Court of Appeal is to determine whether the legal aspect of the question is "extricable" from the factual aspect of the question. If the legal aspect can be extracted, then the factual aspect remains subject to the test of whether it contains a palpable and overriding manifest error, but the legal question is subject only to the test of correctness. See Housen v. Nikolaisen at paragraphs 26 to 37. If the legal aspect can not be extracted then the whole question is subject to the test of palpable and overriding manifest error. IV. The Penticton Airport Procedures