Which statement correctly describes the acceptable methods to deactivate installed equipment (not under MEL)?

Which statement correctly describes the acceptable methods to deactivate installed equipment (not under MEL)?

• A. It can be deactivated if there is an Engineering Order or Service Bulletin
• B. It can be deactivated by MEL authorization or an Engineering Order or Service Bulletin
• C. It can be deactivated only with MEL authorization
• D. It cannot be deactivated

Answer: (B)

Deactivating installed equipment that isn’t on the MEL must be done under proper authority to keep the aircraft airworthy and compliant. MEL authorization provides documented permission to operate with certain equipment inoperative as allowed by the MEL, while an Engineering Order or Service Bulletin can authorize a deactivation when the MEL doesn’t cover that item or condition, outlining the exact steps, limitations, and rationale. Together, these are the formal pathways to safely deactivate equipment: MEL-approved procedures or engineering-directed deactivation via an EO or SB. That is why the statement that it can be deactivated by MEL authorization or an Engineering Order or Service Bulletin is the best choice. The other options are incomplete or incorrect because they omit one of these valid avenues or claim deactivation isn’t allowed.

Deactivating installed equipment that isn’t on the MEL must be done under proper authority to keep the aircraft airworthy and compliant. MEL authorization provides documented permission to operate with certain equipment inoperative as allowed by the MEL, while an Engineering Order or Service Bulletin can authorize a deactivation when the MEL doesn’t cover that item or condition, outlining the exact steps, limitations, and rationale. Together, these are the formal pathways to safely deactivate equipment: MEL-approved procedures or engineering-directed deactivation via an EO or SB. That is why the statement that it can be deactivated by MEL authorization or an Engineering Order or Service Bulletin is the best choice. The other options are incomplete or incorrect because they omit one of these valid avenues or claim deactivation isn’t allowed.