CALGARY — WestJet, Sunwing and Transat said Thursday they were examining their fleets of Boeing 737 Next Generation aircraft for cracks after a U.S. regulator ordered the inspections.

WestJet says it has 43 aircraft that fall under an inspection directive issued by the U.S. Federal Aviation Administration.

The company says it has had no structural cracks in its 737 NG fleet and expects minimal disruptions from the inspections.

Sunwing said it had received the directive from the FAA and will be inspecting its fleet as appropriate but didn’t expect any disruptions to its schedule.

The company did not say how many of its planes require inspection, but it has more than 40 of the Boeing 737 NG aircraft in its fleet.

Transat said it has five 737 NG planes in its fleet plus a temporary one. It said two of the planes would require a visual inspection that would take about an hour, but none of its planes have flown enough to require a more extensive check.

Air Canada says it does not have any of the Boeing 737 NG planes.

The FAA said that if the cracking was not addressed it could lead to a loss of control of the airplane.

The inspection order comes as Boeing remains under scrutiny after two deadly crashes led to a grounding of its Boeing 737 Max aircraft in March.