FAA: Boeing Knowingly Installed Faulty 737 Parts

Boeing faces a $4 million fine for failing to ensure a supplier was delivering airworthy 737 slat tracks and then not rejecting them once the issue came to light, causing the FAA to issue an airworthiness directive to ensure the defective parts were removed from in-service aircraft, the agency said.

A civil penalty letter sent by FAA to Boeing Dec. 6 reveals that a plating process done by Southwest United Industries (SUI) introduced weakness, or hydrogen embrittlement, in 233 sets of slat tracks made in mid-2018. SUI informed slat track manufacturer Kenoca Industries, which told Spirit AeroSystems. Spirit contacted Boeing in September 2018, and recommended the OEM accept the parts “as-is,” the FAA letter said. Boeing rejected this and told Spirit to file a “notice of escapement,” or declaration by a supplier of a problem with its products.

During its work, SUI followed the wrong part-marking procedure, which meant a required protective coating was not applied. This caused some of the markings to be “partially or completely obscured,” the FAA said.

Despite the issues, the parts ended up on Boeing's 737 production lin in Renton, Wash., and some were apparently installed on 133 737NGs delivered from Aug. 16, 2018, to May 2, 2019—including at least one that went to a military customer. The rest may have ended up on 737 MAXs, Boeing determined.

Boeing issued an alert service bulletin on June 4, telling operators to inspect their aircraft for the defective slat tracks. The FAA mandated the checks in a June 10 directive that said the parts could be on 133 NGs and 179 MAXs. The directive did not explain why Boeing could not positively identify which aircraft had the parts. The civil penalty letter said that SUI’s improper coatings made it "difficult to identify the affected parts.”

Boeing said in a Dec. 6 statement that “all affected 737NGs have been inspected” and parts replaced where required. "Further, we will ensure that all inspections and any necessary part replacements are performed on all 737 MAXs before they return to service,” it added.

“Boeing failed to maintain its quality system by failing to detect improperly marked slat tracks, installing improperly marked slat tracks in aircraft, and not managing supplier quality,” the FAA letter said. Boeing used parts “that should have been rejected and subsequently [certified] that the aircraft were airworthy,” it added.

Neither the letter nor Boeing’s statement explain how the parts got into the 737’s production system once the manufacturer realized they did not conform.

Boeing has not received any in-service reports of slat track failures linked to the production issue.