The 1970s was a time of great change in commercial aviation. By 1979 Air Canada, like all major airlines, was radically different in the way it operated from 1970, with the introduction of the B747, INS navigation, longer range and mass air travel generally.
Your brief description of a four-man crew and passenger disembarkation via steps points more to the late sixties than the late seventies, by which time airlines were heading uncertainly towards today's style (lack of style) of air travel. I recommend you chose one or other period to avoid conflicting advice and errors in your text.