The U.S. Federal Aviation Administration has identified more than 300 Boeing Co. 737 aircraft that may have faulty wing parts, the regulator said June 2.
The FAA said 133 Next-Generation jets and 179 Max aircraft contain leading-edge slat tracks that "may have been improperly manufactured and may not meet all applicable regulatory requirements for strength and durability."
Slat tracks are part of an aircraft's wings.
The affected parts "may be susceptible to premature failure or cracks resulting from the improper manufacturing process" of an unnamed Boeing sub-tier supplier, the statement said.
The regulator will require Boeing to remove the said parts from service, while airlines will have 10 days to comply with the directive.
Boeing's 737 Max jets remain grounded globally due to two fatal crashes in the last 12 months.