Describe heavy maintenance.

• A. Quick daily inspections
• B. Whenever the engine must be removed from the airplane for shop maintenance or for test cell operation and troubleshooting
• C. Major engine overhauls during in-flight
• D. Cosmetic repairs on the nacelle

Answer: (B)

Heavy maintenance means work that takes the engine out of service and into a shop for extensive, in-depth care. It involves disassembly, inspection, replacement of components, overhauls, and troubleshooting, with testing in a test cell to verify everything is functioning properly. This level of work is done in a controlled shop environment because it requires thorough access to all parts and detailed procedures that aren’t feasible in the field or during flight.

That’s why the description that specifies removing the engine from the airplane for shop maintenance or for test cell operation and troubleshooting is the best fit. Quick daily inspections are considered light maintenance, not heavy. Cosmetic repairs on the nacelle don’t address the engine’s internals and aren’t heavy maintenance. Major overhauls aren’t performed in-flight; they’re conducted in the shop as part of the heavy maintenance process.