Because you’ve determined that the aircraft can be legally and safety operated without it, you have chosen to deactivate it and placard it “inoperative.” As a result of the above, you are confident that the aircraft is airworthy until the next required inspection, but then what happens? Must you have that broken ADF repaired, replaced, or removed at annual, or can you leave it in place until you do your planned panel upgrade?
FAR 91.405(c) requires that equipment permitted to be inoperative under § 91.213(d)(2) must be “repaired, replaced, removed, or inspected at the next required inspection.” Last year I wrote about the FAA’s De Joseph (2017) legal interpretation which addressed the question of whether an aircraft could continue to be operated “indefinitely” with inoperative equipment installed. The answer was “no.” In other words, it would not be an option to reevaluate the inoperative equipment at the next inspection to confirm that it was still inoperative and determine that it would not negatively affect safety.
The FAA has revisited this position in the Peri (2018) legal interpretation. The question posed in Peri was about the meaning of the term “inspected” in the context of § 91.405(c). The requesting party sought clarification as to whether the discrepancy must be resolved the next time the aircraft undergoes a required inspection, or alternatively, whether an inspection could confirm that the aircraft is still in compliance with § 91.213(d) and the inoperative equipment continues to have no impact on safety.
In order to answer this question, the FAA went back to the original rulemaking. Relying on the preamble for the final 1988 rule, the interpretation reaches the conclusion that “if the inoperative equipment is not repaired, replaced, or removed at the next required inspection, the inoperative item must be inspected again (reevaluated) at that inspection in order to ensure that the discrepancy will not have an adverse effect on the safe operation of the aircraft.” It goes on to explain that operations with inoperative equipment could continue “indefinitely” as long as the reevaluation is appropriately conducted and logged each time the aircraft undergoes a required inspection.
What does this mean for you and your aircraft? As long as the inoperative ADF remains appropriately placarded, and is periodically reassessed as detailed above, it can remain in the panel until such time as you deem it appropriate to remove it.