Which statement correctly describes the relationship between Airworthiness Directives (ADs) and Service Bulletins (SBs)?

Which statement correctly describes the relationship between Airworthiness Directives (ADs) and Service Bulletins (SBs)?

• A. ADs are legally enforceable safety directives; SBs are manufacturer recommendations, some may be made mandatory by ADs or FAA action.
• B. SBs are legally enforceable; ADs are merely recommendations.
• C. SBs apply only to military aircraft; ADs apply to civilian.
• D. SBs are always mandatory.

Answer: (B)

Understanding how Airworthiness Directives and Service Bulletins relate comes down to authority and enforceability. Airworthiness Directives are issued by the FAA to address identified unsafe conditions in an aircraft, and they are legally enforceable. Operators must comply to maintain the aircraft’s airworthiness; noncompliance can lead to grounding or penalties. Service Bulletins are published by manufacturers as recommended maintenance actions or corrective steps. They are guidance, not mandatory by themselves. They become enforceable only when the FAA adopts them into an AD or otherwise requires them through regulatory action. An AD can also cite an SB and require the actions described, effectively making those parts mandatory for the affected fleet. So SBs are not inherently legally enforceable, and ADs are not merely recommendations. SBs can be made mandatory through FAA action or an AD.

Understanding how Airworthiness Directives and Service Bulletins relate comes down to authority and enforceability. Airworthiness Directives are issued by the FAA to address identified unsafe conditions in an aircraft, and they are legally enforceable. Operators must comply to maintain the aircraft’s airworthiness; noncompliance can lead to grounding or penalties.

Service Bulletins are published by manufacturers as recommended maintenance actions or corrective steps. They are guidance, not mandatory by themselves. They become enforceable only when the FAA adopts them into an AD or otherwise requires them through regulatory action. An AD can also cite an SB and require the actions described, effectively making those parts mandatory for the affected fleet.

So SBs are not inherently legally enforceable, and ADs are not merely recommendations. SBs can be made mandatory through FAA action or an AD.