A Service Bulletin SB is document released by manufacturers of product like aircraft, engines, APU, landing gear, appliance or any other components.

Service Bulletin SB may issue by the manufacturer to:

• • Fix safety issue (Mandatory & Alert SB)
• • Avoid potential maintenance errors
• • Increase product reliability.
• • Ease product maintenance ability.
• • Add a new feature.
• • Introduce a wholly new product exchange old one.
• • Enhance aircraft, engine or any other product design.
• • Enhance aircraft, engine or any other product performance.
• • A modification which extend product life.