Boeing Admits Many 737 MAX Planes Have Defective Wing Parts

The Boeing Company on Sunday said it’s warning airlines of a defective wing part that might pose a danger to more than 300 of its 737 planes worldwide even as it struggles with anger from airlines, pilots and the flying public after two fatal crashes of its Boeing 737 MAX 8 jetliner.

Boeing said it had uncovered faulty “leading edge slat tracks” that don’t meet strength and durability standards and might affect the performance of a jet as it takes-off.

Leading edge slat tracks are rails that mount a plane’s leading edge slats. These slats are aerodynamic control surfaces that extend from the front of the wing during take-off to impart more lift.

The U.S. Federal Aviation Administration (FAA) said more than 300 Boeing 737 jetliners, including the MAX, might be affected by this problem. It found that up to 148 leading edge slat tracks manufactured by a single supplier are affected by the problem.

Boeing believes 20 737 Max and 21 737 NG planes could have defective slat tracks. On the other hand, the FAA advised airlines to check an additional 179 Max jetliners and 133 NGs to determine if their slat tracks are also faulty.

Of the total number of 737s with faulty slat tracks, 33 Max and 32 NG planes are in the United States.

“The affected parts may be susceptible to premature failure or cracks resulting from the improper manufacturing process,” said the FAA.

The FAA said a leading edge slat track failure won’t likely crash a 737 but it might damage an aircraft while in flight. It said some tracks that did not meet manufacturing standards might need to be replaced.

Boeing and the FAA said if the tracks are found to be defective, airlines should replace them before returning the 737s to service.

Boeing said it discovered the problem Friday after employees found some of the parts weren’t heat treated. This finding led Boeing to believe there might be a safety issue with the parts in question, hence the warning issued to airlines.

The FAA said it will issue an airworthiness directive mandating service actions to remove the slat tracks in question and that airlines will have to follow within 10 days. It said it’s also alerted other international civil aviation authorities about this new problem.

Boeing said it plans to provide replacement parts for airline customers affected by the slat track issue “to help minimize aircraft downtime while the work is completed.” The replacement process might take a day or two to complete.

The 737 NG is the model that preceded the 737 Max first delivered to airlines in 2017.