Photo: The Canadian Press

TORONTO — Air Canada and WestJet encouraged travellers headed to or from the U.S. to check their flights before going to the airport after a key computer outage at the U.S. Federal Aviation Administration caused delays.

WestJet said six flights were delayed Wednesday morning because of the computer outage and none were cancelled, while Air Canada said the outage would have an effect on its transborder operations, but that it was not possible to determine the extent of the delays.

The FAA issued a grounding order for all departing aircraft Wednesday morning due to a problem with what is known as the Notice to Air Missions System (NOTAMs). The order remained in place until just before 6 a.m.

Before commencing a flight, pilots are required to consult NOTAMs, which list potential adverse impacts on flights, from runway construction to the potential for icing. The system used to be telephone-based, with pilots calling dedicated flight service stations for the information, but has moved online.

The NOTAM system broke down late Tuesday, leading to more than 1,000 flight cancellations and more than 6,000 delayed flights by 8 a.m. Wednesday, according to the flight tracking website FlightAware.

Separately, Canada’s NOTAM entry system also experienced an outage between 7:20 and 10:15 a.m., said Nav Canada’s manager of government and media relations, Vanessa Adams.

“We are still investigating the root cause of the failure,” she wrote in an email.  “At this time, we do not believe the cause is related to the FAA outage experienced earlier today.”

Nadine Ramadan, a spokesperson for Federal Transport Minister Omar Alghabra, said in an afternoon email that their office had been in touch with Nav Canada.

Earlier in the day, at a news conference in Port Colborne, Ont., Alghabra said he had reached out to his U.S. counterpart, Transportation Secretary Pete Buttigieg, about the U.S. NOTAM troubles.

“This was obviously a surprise. It was an unplanned interruption,” Alghabra said.

“We still don’t know all the facts yet, but good news is that I am hearing that traffic has restarted again, so we will stay in coordination with our U.S. partners to understand what had happened and what can we do to avoid similar interruptions.”