A Boeing 737 MAX sits outside the hangar during a media tour at the Boeing plant in Renton, Washington.
Matt Mills McKnight | Reuters
An electrical problem that led to the suspension of operations of dozens of Boeing 737 Max planes has spread after engineers found similar defects in the ground elsewhere in the cabin, industry sources said on Friday.
Airlines fired dozens of Max planes a week ago after Boeing warned of a production-related electrical grounding problem in a backup power control unit located in the cockpit on some newly built planes.
Since then, suspected grounding problems have been found in two other places on the flight deck, sources said.
These include the storage shelf in which the affected control unit is kept and the pilot-oriented instrument panel.
Boeing had no immediate comment on the larger issue, which was first reported by Aviation Week.
Boeing shares closed 1.2%.
The problem – which affects about a fifth of Max aircraft on the market – is the latest issue to hit the best-selling Boeing model, but it is not related to design issues that have contributed to a global safety ban of 20 months after two fatal accidents. .
Boeing is expected to develop bulletins advising airlines on how to address grounding or electrical problems designed to maintain safety in the event of a surge.
US 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 reports needed to begin work on about 90 aircraft affected by the suspension.
The planner initially told airlines that a repair could take several hours or days on the plane, according to a notification seen by Reuters when the partial suspension was first announced.
The problem was followed by a change in the material layer, once the production of the 737 Max model was resumed last year.
Almost all of the affected aircraft were built before Max’s deliveries resumed in December, shortly after US regulators lifted the fleet-level ban caused by the 2018 and 2019 accidents.
Boeing said it plans to gradually increase production of the 737 Max from an unspecified current “low rate” to a target of 31 aircraft per month by early 2022. Industry sources estimate that it currently produces about four aircraft per month.
Airlines sources say Boeing has not delivered any Max planes since the electrical problem was identified last week.