It can be confusing at St Hubert near Montreal as both languages are used at the same time, and there have been incidents. Of course if you understand French you still have to listen very carefully as Quebecois is not the same, but they still say it only once...
.. and at Gatineau, just across the river from Ottawa. At the OFC we sometimes flew across to it for circuit bashing if Ottawa International was particularly busy (rare, fortunately). And yes, despite being happy in European (Swiss) French since childhood, and working in a majority francophone office in Ottawa, it took me quite a while to attune myself to spoken Quebecois, even in formulaic aeronautical exchanges.
AIUI, in Canada all Federal (including military) and designated international airports should offer ATC in either language, although I suspect few pilots request French in BC! But elsewhere, only one need be available. This means that in more isolated parts of Quebec, anglophone pilots should theoretically assume that others in the air and on the ground may be able to use only French; we used to warn visiting US pilots of this when cleared Customs in Ottawa and parked on the OFC apron overnight before continuing to some posh hunting lodge in Northern Quebec! They were openly incredulous. However, I never met a Canadian francophone in aviation who was not fully competent in English.
Happy to be corrected or brought up to date by MichaelP or others, of course.
[In the Canadian Federal Civil Service, all internal promotions are probationary, and dependent on passing a language test appropriate to the higher grade in one's less familiar official language; failure means the promotion is lost, but paid one-to-one language tuition/refresher is available. The higher the grade, the tougher the test, so that seniors should be completely bilingual. And all employees are entitled to supervision and appraisal in their familiar language, so in DND I was expected to be able to do both written reports and interviews in French for francophone subordinates and promotion or job applicants. Fair enough.
All public-facing Federal employees are meant to be competent in both languages nationwide. One of my francophone colleagues, perfectly bilingual, once returned from vacation; he was indignant that on arrival in Vancouver from the US he had spoken to Customs/Immigration in French, and was delayed while the officer sought a more competent colleague. He was making a point, but his indignation was justified]
(mere guide at) Jet Age Museum, Gloucestershire Airporthttp://www.jetagemuseum.org/
TripAdvisor Excellence Award 2015http://www.tripadvisor.co.uk/Attraction ... gland.html