When should the flow meter be reset to zero during servicing?

Resetting the flow meter to zero when connecting the pre-oiler is essential for obtaining an accurate measurement of the oil being introduced into the system. The pre-oiler is designed to circulate oil through the engine components before starting, ensuring that all moving parts are adequately lubricated. By resetting the flow meter at this point, you can track the exact amount of oil being used during the pre-oiling process, which is crucial for maintenance and checking the health of the engine.

This practice ensures that once you begin adding oil, you have a clear starting point to measure against, allowing for more precise monitoring and avoiding overfilling or underfilling the oil system. Accurate readings from the flow meter also contribute to effective maintenance records, which are important for the overall performance and reliability of the aircraft.