Boeing 737s must now be checked for cracks near the drain mast

The US aviation regulator proposes new mandatory inspections for all Boeing 737-600, -700, -800, and -900 series airplanes. Airlines will have to repeatedly check the fuselage skin around the aft drain mast for cracks and corrosion.

This is a routine safety update, but it adds to the ongoing scrutiny of Boeing's manufacturing quality. Airlines will now face additional maintenance costs and potential grounding time for these inspections. It means more work for maintenance crews and more potential delays for passengers.