MONTREAL – Air Transat has been ordered to change its rules to compensate passengers when flights are advanced by more than 45 minutes.

Passengers would be eligible to a refund or alternative flights if they can’t accommodate earlier flight times.

The Canadian Transportation Agency ruled in favour of passenger rights advocate Gabor Lukacs, who has challenged various rules of several airlines.

In a ruling issued Thursday, the regulator determined that Air Transat’s existing rules aren’t reasonable or balanced.

It says the Montreal-based airline — a division of tour company Transat A.T. (TSX:TRZ.B) — should give passengers the same remedies when flights are advanced as when they are delayed.

It ordered Air Transat to make the changes by Sept. 23.

Air Transat proposed changes that wouldn’t have protected passengers whose flights are advanced by less than six hours or who were notified by more than 48 hours in advance. Compensation would depend on individual circumstances.

It wasn’t immediately clear how often Air Transat advances flights.

Lukacs says Sunwing — another vacation package company — voluntarily changed its rules earlier this summer after he launched a similar challenge.