Credits: CRAIG ROBERTSON/QMI AGENCY
In his annual report, Official Languages Commissioner Graham Fraser called on the airline to improve its service as quickly as possible.
Fraser's audit found Air Canada failed to offer its employees enough language training so they could offer full bilingual service to clients.
In July 2011, Air Canada client Michel Thibodeau won a $12,000 settlement from the airline after employees for the carrier failed to serve him in French on a flight.
The airline appealed the decision and the Federal Court is expected to hand down its ruling later this year.
Fraser also released his findings on an investigation into the level of bilingualism in the national capital.
He found that most businesses in Ottawa greet customers in English only, but that customers can indeed receive service in both languages.
Fraser's office received 518 complaints relating to the federal language act in the year 2011-12.
The bulk of those complaints - 48% - originated in the National Capital Region.
Just 17% of Canadians are bilingual, according to Fraser's figures - despite the fact the Official Language Act is in its fifth decade.