Boeing Ordered to Replace 737 Wing Parts Prone to Cracking

Airlines worldwide must inspect 312 of Boeing Co.’s 737 family of aircraft, including some of the grounded 737 Max, because they have wing components that are prone to cracking and must be repaired within 10 days, U.S. aviation regulators said Sunday.

Boeing informed the Federal Aviation Administration that so-called leading edge slat tracks may not have been properly manufactured and pose a safety risk, the agency said in an emailed statement. The parts allow the wing to expand to create more lift during takeoff and landing.

While less critical than the global grounding of its 737 Max since March, Boeing’s latest production issue adds another headache for a management team trying control the fallout from two deadly crashes and get the U.S. manufacturer’s top-selling plane flying again. The head of the International Air Transport Association warned airline CEOs at the industry’s annual gathering this past weekend that the plane-approval process is damaged and the industry is under scrutiny.

The FAA plans to issue an order calling for operators of 737 planes worldwide to identify whether the deficient parts were installed and to replace them, if needed. A complete failure wouldn’t lead to a loss of the aircraft, the FAA said, but could cause damage during flight.

Boeing has notified operators of the planes about the needed repairs and is sending replacement parts to help minimize the time aircraft are out of service, the company said in a statement. The slat tracks in question were made by a supplier to Spirit AeroSystems Holdings Inc., Boeing said in an email.

Boeing has identified 148 parts made by a subcontractor that are affected. The parts may be on a total of 179 737 Max aircraft and 133 737 NG planes worldwide, including 33 Max and 32 NG aircraft in the U.S., the FAA said.

The NG, or Next Generation, 737s are a predecessor to the Max family.

Southwest Airlines Co., which had 753 Boeing 737s in its fleet at the end of March, is waiting on additional guidance from the aircraft maker as it prepares for any needed inspections, said Chris Mainz, a spokesman for the Dallas-based carrier.

“This impacts about a handful of our aircraft, and we do not anticipate any impact to our operation,” Mainz said in an email. Southwest’s fleet includes 34 grounded Max aircraft.

American Airlines Group Inc. said the inspection requirement will not affect its 737 NG fleet or its flight schedule. American has one of the 20 Max planes identified as being most likely to have the parts in question, said Ross Feinstein, a spokesman for the airline. It hasn’t determined whether its remaining 23 Max aircraft are among those that will need to be checked, he said. American has about 300 737-800s in its fleet.

United Continental Holdings Inc., Delta Air Lines Inc. and Alaska Air Group Inc. didn’t immediately comment on their 737 fleets.

The deficient parts may be on fewer of the identified planes, Boeing said. While the full number of jets must be inspected, 20 Max and 21 NG aircraft are “most likely” to have the suspect parts installed, according to the company.

The 737 Max has been grounded worldwide since March 13 after two fatal crashes tied to a malfunction that caused a flight control system to repeatedly drive down the plane’s nose. Boeing is finalizing a software fix along with proposed new training that will be required before the planes fly again.