Systems operational at Montreal Trudeau airport after hours of ‘connectivity problems’

“Connectivity problems” on several Montreal-Pierre Elliott Trudeau International Airport systems that caused a slowdown in operations Tuesday, including flight delays for several hours, is over.

Aéroports de Montréal (ADMTL) said just before 10:30 p.m. on Tuesday that their systems were back in operation.

“The ADM team and those of its service providers would like to thank all passengers and airport community partners,” they said. “Including carriers, for their patience in this exceptional situation.”

A total of 118 flights were delayed — 57 at arrival and 61 at departures.

As the resumption is gradual, they recommend travellers validate their flight schedule before travelling to YUL.

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The YUL systems serving our passengers are back in operation. We still recommend that travellers validate their departure and arrival information on their airline's website, before coming to YUL. Thank you for your understanding.

— YUL Aéroport international Montréal-Trudeau (@yulaeroport) March 26, 2025

Earlier in the day, ADMTL said the airport was operational, but travelers saw hours-long delays at check-ins and security checkpoints.

ADMTL media relations advisor Eric Forest told CityNews, that “a contingency plan has been deployed and our teams are working to restore the situation as soon as possible.”

However, the airport saw around 12 hours worth of delays or even flights pushed to Wednesday.

“The service provider in charge of telecoms for YUL carried out a software update on the equipment last night,” explained Forest. “Which caused several systems to fail.”

In a statement posted to X, Bell Canada said that they were conducting these network upgrades with the airport team and encountered “unexpected behaviour” with the final upgrades which then took the connection offline.

“We recognize that this has greatly inconvenienced people travelling through and working at [the airport] and are fully aware of the impact this has on those affected,” they said.

An investigation is underway to determine the source of the problem that caused the outage.

Forest explains that “corrective and preventive measures will be deployed in the network architecture in conjunction with the suppliers concerned.”

More on the delays earlier in the day

As of 9:00 a.m. Tuesday morning, the wait and delays were mainly at check-in for Air Canada and Sunwing domestic/international flights.

“We recommend as usual that all passengers, regardless of destination or airline, plan ahead and arrive at the airport well in advance with that in mind,” Forest explained.

In an update at 9:21 a.m. posted to social media, the airport said that the situation was still ongoing, which was considerably slowing down passenger processing, particularly at check-in.

Adding that flight schedules on their website were not being updated.

“Please make sure to validate your departure or arrival information on your airline’s website,” they wrote. “Our teams are currently working with our supplier’s team to rectify the situation.”

At 11:27 a.m. the airport, once again sharing on social media, said that the situation was still ongoing at YUL.

“Plan your travels, regardless of your destination,” they added. “And if possible, please register online, before coming to YUL.”

“The ADM website chat service is also accessible,” said Forest. “Agents are available to respond to travellers.”

As of 3:30 p.m. Forest told CityNews that the system connectivity problems affecting operations at YUL were still ongoing.

“Alternative solutions have been deployed, enabling some systems to be operational again,” he said. “But delays are to be expected due to this exceptional situation.”

“This outage does not affect air navigation systems, so aircraft continue to take off and land, despite schedule delays.”

For those next few hours, travellers were advised to:

1. Check their flight schedule on their air carrier’s website.

2. Arrive at least 4 hours early.

3. Check in online before arriving at the airport.

4. For those without checked baggage, proceed directly to the security checkpoint.