Under what condition should the operator of a small UA establish a scheduled maintenance protocol?

Why: This is a published FAA UAG sample knowledge-test question. AC 107-2A explains that if the manufacturer does not provide scheduled maintenance instructions, "the operator should establish a scheduled maintenance protocol," documenting repairs and time-in-service to build a reliable maintenance schedule over time.

• AC 107-2A describes maintenance — scheduled and unscheduled — as necessary for every small UAS, not an optional practice that can be skipped.
• The AC does not describe the FAA mandating a maintenance schedule only reactively after an accident; the recommendation is proactive, applying whenever the manufacturer leaves a gap.