What is a Service Bulletin (SB) in aviation?

A Service Bulletin (SB) is a crucial communication issued by an aircraft manufacturer that provides important information regarding safety or performance improvements for a specific aircraft model. This may include recommendations for modifications, inspections, or maintenance practices that need to be implemented to enhance the aircraft's reliability, safety, or efficiency.

Manufacturers release Service Bulletins in response to new information acquired from service experiences, regulatory changes, or advancements in technology. These bulletins help ensure that the aircraft operates within the most updated safety and performance standards.

The other choices do not accurately define a Service Bulletin. For instance, a mandatory service check refers to specific regulatory requirements, not general advisories, while financial reports and specifications do not pertain to safety or performance action but rather account for operational data or technical data about the aircraft.