The potential electrical problem that prompted airlines to take dozens of 737 MAX jets out of service last week is affecting more parts of the aircraft’s flight deck than was previously known, Boeing Co. said.
The aviation giant said last week that it had instructed 16 MAX operators to inspect their aircraft for a possible electrical problem identified during an aircraft meeting in Seattle. The manufacturing issue, which according to Boeing is now affecting components in some places, will have to be addressed in about 90 aircraft in aircraft fleets as well as in many aircraft that have not been delivered.
Airlines were eager to put their MAX jets back into use if they were ready for a busy summer, but carriers said they could largely do without the planes by replacing other planes. Nevertheless, the newly discovered shortcoming threatens the efforts of airlines and Boeing to restore passenger confidence in the aircraft. The challenge comes because the aircraft maker is also working on resolving quality issues caused by some of its other commercial and military aircraft.
The issue, which was announced last week, relates to the electric grounding circuit for the assisted power unit in certain electronic systems in the aircraft. A change in the way the unit was installed during production in early 2019 could have interrupted the grounding; in some circumstances, it could affect how the backup power source works, Boeing, the Federal Aviation Administration and airlines said last week.
The same production changes also had an impact on the grounding path of the aircraft’s main instrument panel and on the rack that houses the auxiliary power unit, Boeing found during its recent assessments. The areas also need to be explored and adapted, Boeing said.