WICHITA, Kan. (KSNW) — Spirit AeroSystems says it has identified a quality issue on the aft fuselage section of certain models of the 737 fuselages built in Wichita. Spirit says it has notified Boeing about the issue.

Forrest Gossett, senior manager of Spirit AeroSystems Corporate Communications, said it is “not an immediate safety of flight issue.”

Boeing sent KSN News a statement agreeing it is not an immediate safety of flight issue.

It said, “A supplier has notified us that a non-standard manufacturing process was used during the installation of two fittings in the aft fuselage section of certain 737-7, 737-8, 737-8-200 and P-8 model airplanes, creating the potential for a non-conformance to required specifications.”

Boeing said the in-service fleet can continue operating safely. But it said the issue will probably affect “a significant number of undelivered 737 MAX airplanes, both in production and in storage.” It also expects the issue will affect some upcoming 737 MAX deliveries.

“We regret the impact that this issue will have on affected customers and are in contact with them concerning their delivery schedule,” Boeing said in a statement. “We will provide additional information in the days and weeks ahead as we better understand the delivery impacts.”

Boeing has notified the FAA and is working to inspect and replace the fittings as needed.

Gossett said that Spirit has processes to address its production issues, which the company follows.

“Spirit is working to develop an inspection and repair for the affected fuselages,” Gossett said. “We continue to coordinate closely with our customer to resolve this matter and minimize impacts while maintaining our focus on safety.”

Spirit makes approximately 70% of the 737 for Boeing, including fuselage, pylon, wing leading edges, thrust reverser, and engine nacelle.