What kind of publications do manufacturers use to notify owners of design defects?

Manufacturers utilize service bulletins and service letters as official communications to notify aircraft owners of design defects. These documents serve as critical resources that provide essential information regarding safety issues, maintenance procedures, and modifications necessary for addressing identified defects in an aircraft's design or operation.

Service bulletins typically outline the problem, the potential risks associated with it, and recommended corrective actions, including inspections or modifications that owners or operators should undertake to ensure safety and compliance with airworthiness standards. Service letters, while similar to bulletins, may provide less critical information but still inform owners of relevant updates concerning aircraft operation or maintenance.

In contrast, maintenance updates and technical memos may provide general guidance but do not specifically focus on notifying about design defects. Owner's instructional guides are designed to provide operational information and safety practices but do not address defects or necessary corrective actions. Safety inspection reports are assessments of the current condition and compliance of an aircraft, but they are not primarily for communicating design defects.