Which maintenance list tracks maintenance due items based on hours, cycles and landings?

• A. ACMS Maintenance Due List (MDL)
• B. AMMIS Reports
• C. OPNAV 4790
• D. Maintenance Schedule List

Answer: (A)

Usage-based maintenance is tracked by the Aircraft Condition Monitoring System’s Maintenance Due List. The ACMS gathers flight usage data—hours, cycles (takeoffs/landings), and sometimes landings count—and compares it to life limits for each item. When a threshold is reached or approaching, the Maintenance Due List flags that item so maintenance can be scheduled before it becomes overdue. This is the specific, usage-driven tool used to plan and execute maintenance tasks.

AMMIS reports and OPNAV 4790 serve other purposes—AMMIS provides various maintenance data reports, and OPNAV 4790 is the governing manual/document format for maintenance records. Maintenance Schedule List is not the standard usage-based list generated from flight data.