Boeing (BOE, Washington National) has said that deliveries of its B737 MAX family aircraft during the first quarter of 2026 could be delayed due to wiring flaws.

“Our B737 program is performing rework on a group of airplanes to fix wires that have small scratches due to a machining error,” the manufacturer said, as quoted by Reuters, adding that production on the narrowbodies nevertheless continues at the current rate of 42 jets per month.

Boeing intends to increase the rate to 47 per month later this year, as it opens a fourth assembly line at its Everett plant this summer. It expects to ramp up to a maximum of 63 aircraft a month over the next few years.

The company did not clarify if the scratches on the wires had been caused by a supplier or by Boeing itself. It has informed the US Federal Aviation Administration (FAA) and customers about the issue.

All in-service B737 MAX airplanes can continue to operate safely, Boeing said, and it does not expect the issue to impact its goal to deliver over 500 jets of the family in 2026.