What should be checked for tightness on new engines during the first 50-hour inspection?

During the first 50-hour inspection of new engines, one of the critical items to check for tightness is the thrust bearing nuts. This is important because proper torque on these components is vital for ensuring that the engine operates smoothly and efficiently. The thrust bearings are responsible for handling the axial loads that occur during engine operation, and any looseness can lead to increased wear, potential failure, and catastrophic damage to the engine.

In contrast, while items such as propeller bolts, fuel lines, and oil filters are also important maintenance considerations, they are typically evaluated under different maintenance schedules or specific inspection routines. Proper checking of thrust bearing nuts is paramount in the early life of an engine to avoid any operational issues that could arise from improper assembly or settling of components. Ensuring these mechanical connections are secure helps maintain the engine's reliability and safety during operation.