Inspections of Boeing (BA 2.91%) 737 MAX jets grounded last week have reportedly turned up additional potential electrical issues, raising questions about the scale and size of a potential fix.

Boeing on April 8 requested that about 60 737 MAX jets be grounded temporarily to address potential electrical system problems in the jets, a move that impacted 16 airlines, including Southwest Airlines (LUV 0.24%), American Airlines Group (AAL -0.21%), and United Airlines Holdings (UAL -1.02%).

Boeing's 737 MAX in flight.

Image source: Boeing.

Boeing, according to an Aviation Week report, has since discovered the issues extend beyond the area originally flagged. The initial issue was said to be a problem with the electrical insulation, which could lead to grounding issues.

There is not yet any indication the investigation will lead to a wider recall, though it is possible the planes affected could require a costly overhaul of their electrical systems.

The reports come at a difficult time for both the 737 MAX and Boeing. The plane was pulled out of service for more than 18 months after a pair of fatal accidents, only returning to the air last fall. So far, there has been little talk of consumer hesitancy to board the plane, but both Boeing and the airlines would prefer to avoid a fresh round of negative headlines concerning the plane.

The issue also adds to Boeing's laundry list of recent manufacturing issues. In addition to its 737 MAX problems, Boeing's 787 Dreamliner recently dealt with a delivery halt to address issues with its carbon fiber skin, and a new version of the 777 has been delayed by a few years due in part to development issues.

On the military side, Boeing's long-troubled KC-46 tanker in recent years has dealt with issues including debris left inside after manufacture and cargo-fastener issues.