On Sunday, Boeing Co. (NYSE: BA) notified the U.S. Federal Aviation Administration (FAA) that the company had determined that as many as “148 parts manufactured by a Boeing sub-tier supplier” may be defective. The parts, known as slat tracks, may develop premature failure or cracks “resulting from the improper manufacturing process.”
Boeing told the FAA that it has identified 65 of its 737 aircraft in the United States and a total of 312 worldwide that may have the “suspect” parts installed. In a statement, the FAA noted: “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 fight.”
The issue involves both the 737 MAX aircraft and the prior 737 NG (next generation) models. The FAA said it would issue an airworthiness directive that would “mandate” the steps Boeing must take to identify and remove the defective parts. Airlines operating the affected aircraft will be required to take action within 10 days.
Boeing’s current issues with its 737 MAX aircraft began following a crash that killed 189 passengers and crew in Indonesia last October. A second crash in Ethiopia in March killed 157 people, and the cause of both crashes has resulted in changes to the anti-stall system Boeing used for the 737 MAX family. The entire worldwide fleet of 737 MAX airplanes, some 371, has been grounded since March 13, when the FAA finally grounded the plane in U.S. air space. Boeing’s 737 MAX family is the company’s bread-and-butter plane.
The problem with the slat tracks is not the first time these parts have been an issue for Boeing. In 2007, a China Airlines 737 burst into flames in Okinawa shortly after 165 passengers were safely evacuated. The cause of the blast, according to the FAA report, was the failure by maintenance workers to replace a part following a routine inspection. The loose part was pushed through the barrier between the slat track and the wing fuel tank, creating a major leak once the plane had landed. The slats are the hinged panels at the front of a plane’s wing that are raised during landing.