Boeing has reported a manufacturing defect that will require replacing the leading edge slat tracks on a small subset of 737NG and MAX aircraft.
Airlines that are affected by the issue have ten days to identify and remove the faulty parts, as instructed by an airworthiness directive issued by the FAA.
“Boeing has informed the FAA that certain 737NG and 737 MAX leading-edge slat tracks have been improperly manufactured and may not meet the applicable requirements for strength and durability,” it states.
“The affected parts may by susceptible to premature failure or cracks resulting from the improper manufacturing process. Although a complete failure of a leading-edge slat track would not result in the loss of the aircraft, a risk remains that a failed part could lead to aircraft damage in flight.”
The FAA added that Boeing has identified up to 148 parts produced by an unidentified ‘sub-tier supplier’ as being affected. Globally, the issue affects 133 NG and 179 MAX aircraft.
A statement from Boeing said it had identified 21 737NGs most likely to have the parts fitted. In the interest of being thorough has called all airlines to check an additional 112NGs.
“A separate service bulletin will go to 737 MAX operators to do inspections before the MAX fleet returns to service,” adds Boeing. It appears that at east 20 MAX aircraft are affected, but operators will be asked to check an additional 159 of the type to ensure a full assessment.
Boeing will send replacement parts to customers to help minimise downtime, To replace the slat tracks takes about two days.