Under what condition may inoperative equipment deferred under a 14 CFR Part 91 MEL remain deferred?

The condition under which inoperative equipment deferred under a 14 CFR Part 91 Minimum Equipment List (MEL) may remain deferred is that it must be inspected regularly and pose no hazard to the safety of the operation. The MEL allows operators to maintain flight operations with certain equipment inoperative, as long as the procedures and operational limitations specified in the MEL are followed. This includes ensuring that the inoperative equipment does not compromise the safe operation of the aircraft, which is why ongoing inspections are critical.

Maintaining the aircraft's safety and adherence to regulatory requirements is paramount; hence, ensuring that the inoperative equipment is adequately managed and does not present a flight safety issue is key to deferring its maintenance for the duration allowed. This approach ensures that operational flexibility is balanced with a strong emphasis on safety during flight operations.