[dragnet2]

If aircraft flights are being cancelled for serious issues, “All the time” at the last minute just prior to take offs, maybe they should go out of business. Engine failures during take off at low altitudes can lead to death for all.

[volare737]

Yes they are cancelled “all the time”. It it simply precautionary. It is called an over abundance of caution.

The vast majority of the time, they are not cancelled, though, but the flight is just switched to a different aircraft. That is precisely why flying is the still the safest mode of transportation by far.