This is the best summary I could come up with:
The change stems from a directive released by the Federal Aviation Authority (FAA) in the U.S., which was prompted by the results of in-flight tests that showed using the engine anti-icing system in dry air for more than five minutes in certain conditions can cause overheating and result in "severe engine inlet cowl damage."
WestJet and Swoop did not respond to the CBC before publication with the number of planes affected in their fleets.
Air Canada, WestJet and Flair Airlines acknowledged the directive and said the changes would not have any effect on passenger service.
Air Transat is working with the lease provider of their two planes and also said that the changes would have no impact on their schedule.
The directive is just the latest issue faced by the 737 MAX, which Canadian airlines now refer to as the 737-8.
During the grounding, Boeing redesigned the plane's Manoeuvring Characteristics Augmentation System, which was blamed for two high-profile crashes.
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