A Boeing 737 MAX is sitting outside the hangar during a media tour at the Boeing plant in Renton, Washington.
Matt Mills McKnight | Reuters
An electrical problem that caused the suspension of the service of dozens of Boeing 737 Max aircraft has widened after engineers found similar grounding defects elsewhere in the cockpit, industry sources said Friday.
Airlines took dozens of Max aircraft out of service a week ago after Boeing warned of a production-related electrical grounding problem in a backup power control unit located in the cockpit of some newly built aircraft.
Since then, suspicious grounding problems have been found at two other places on the flight deck, sources said.
These include the storage rack where the affected control unit is kept and the instrument panel facing the pilots.
Boeing made no immediate comment on the broader issue, which was first reported for Aviation Week.
Boeing shares closed up 1.2%.
The problem (affecting about a fifth of Max’s aircraft on the market) is the latest issue to plague Boeing’s best-selling model, but it is unrelated to design issues that contributed to the worldwide safety ban. for 20 months following two fatal accidents. .
Boeing is expected to draft bulletins to advise airlines on how to troubleshoot grounding problems or electrical paths designed to maintain safety in the event of a voltage surge.
U.S. regulators must first approve the bulletins.
While most analysts say the solution is expected to be relatively straightforward, no details were immediately available on the timing of the repair bulletins needed to begin work on some 90 aircraft affected by the suspension.
According to a notification seen by Reuters when the partial suspension was first announced, the aircraft manufacturer had initially told airlines that a repair could take hours or several days per aircraft.
The problem goes back to a change in material coating once production of the 737 Max resumed last year.
Nearly all of the affected aircraft were built before Max deliveries resumed in December, shortly after U.S. regulators lifted the ban on the entire fleet caused by the 2018 and 2019 crashes.
Boeing has said it plans to raise production of the 737 Max gradually, from an unspecified current “low rate” to a target of 31 aircraft a month in early 2022. Industry sources estimate it currently produces about four aircraft a month.
Airline sources say Boeing has not delivered any Max aircraft since the electrical problem was identified last week.