The potential electrical problem that caused airlines to take dozens of 737 MAX aircraft out of service last week affects more areas of the aircraft’s flight deck than previously known, Boeing Co. said.
The aerospace giant said last week that it had told 16 MAX operators to inspect their planes for a possible electrical problem identified during the assembly of a Seattle plane. The issue of production, which Boeing now says affects components at several locations, will have to be addressed in about 90 aircraft in the air fleets, as well as in many undelivered aircraft.
Airlines have been keen to get their MAX planes back on track as they prepare for a busy summer, but carriers say they have largely managed to cope without planes by replacing other planes. However, the newly discovered defect threatens to undermine the efforts of airlines and Boeing to restore passenger confidence in the aircraft. This challenge comes as the aircraft manufacturer is also working to address the quality issues that have plagued some of its other commercial and military aircraft.
The problem revealed last week involved the electrical grounding route for the backup power supply unit in certain electronic systems on the plane. A change in the way that unit was installed during production in early 2019 could have disrupted that grounding path; In some circumstances, this could affect the way the backup power supply works, Boeing, the Federal Aviation Administration and airlines said last week.
The same production changes also affected the grounding path of the aircraft’s main instrument panel and the shelf that houses the backup power supply unit, Boeing found during its recent assessments. These areas need to be inspected and modified as well, Boeing said.