Airlines cannot blame factors they “should have known about” to deny passengers compensation for poor service, federal regulators said yesterday. The Canadian Transportation Agency itemized excuses it would no longer accept under Air Passenger Protection Regulations.

Compensation for flight delays must be paid “except in exceptional circumstances which regulations will identify,” the Agency wrote in a consultation paper. Exceptions must be spelled out for the benefit of travelers, it said.

“Circumstances that would not be considered exceptional: flight crew or cabin crew unavailability, staff shortages at the airline, technical problems that are an inherent part of normal airline operations, any situation the airline knew about or should have known about when it sold the ticket to the passenger, and any action or failure to act by the airline or others with which the airline has a contractual relationship,” wrote the Agency.