What are the two categories of heavy maintenance?

• A. Limited and unlimited
• B. Major and minor
• C. Overhaul and repair
• D. Deferred and non-deferred

Answer: (A)

In turbine engine overhaul practice, heavy maintenance is categorized by scope into two levels: limited and unlimited. Limited heavy maintenance covers a predefined, restricted set of tasks that can be completed within an approved time frame and with a defined tooling and process plan. Unlimited heavy maintenance allows the full range of tasks permitted by the maintenance data, including extensive disassembly, thorough inspection, and component replacement, often leading to a complete overhaul.

This distinction matters because it guides the depth of work, required resources, and certification steps. The other options describe aspects like severity (major vs minor), type of work (overhaul vs repair), or scheduling (deferred vs non-deferred), which are not the standard way this maintenance category is defined.