MONTREAL - An air passenger rights advocate has filed a lawsuit against the Canadian Transportation Agency and Air Transat over a decision related to incidents last summer that left hundreds of passengers stranded on the tarmac for hours.

Gabor Lukacs is asking the Federal Court of Appeal to overturn the regulator's decision in November to waive the $295,000 fine it imposed after finding the Montreal-based airline had committed several violations of transportation rules.

Lukacs says the fine was just a "slap on the wrist" that is far below the level included in its enforcement manual.

He says there is no deterrent value if fines are reduced by the amounts passengers receive in compensation.

Lukacs wants the penalty overturned and sent back to the CTA for reassessment. He is also asking the court to rule that the regulator doesn't have the authority to waive penalties for violations.

Passengers were kept on board two flights that were diverted to the Ottawa airport last July due to bad weather for more than five hours.

The Canadian Transportation Agency and Air Transat were not immediately available for comment.