Which of the following is NOT considered elementary work?

Overhauling an aircraft engine is a complex task that involves extensive disassembly, inspection, refurbishment, and reassembly of engine components. This type of work requires advanced skills, specialized knowledge, and often significant time and tools, and it is indicative of major maintenance activities rather than basic or elementary ones.

In contrast, routine servicing usually involves scheduled maintenance procedures that help keep the aircraft operating safely and efficiently, and are straightforward enough to be classified as elementary work. Minor repairs, while they might involve some disassembly or adjustment, typically do not require sophisticated skills or extensive time. The replacement of light bulbs is also considered elementary work because it is a simple task that typically involves basic hand tools and straightforward techniques. Thus, the differentiation between elementary work and more complex tasks like overhauling an engine is key to understanding why this specific answer is appropriate in the context of maintenance classifications.