What should you ensure regarding Ng to prevent the loss of engine oil?

The focus on Ng, or gas generator speed, is critical for maintaining proper engine function and preventing oil loss. Ensuring that Ng is at 0% indicates that the engine is not operating. Operating at 0% is significant during specific emergency scenarios, where the engine might be at idle or not engaged at all, thus preventing the potential ejection of oil that could occur at higher operational speeds.

In typical operational settings, maintaining a certain Ng level can be vital to ensuring adequate oil pressure and minimizing leaks or loss of oil, but having Ng at 0% effectively prevents the engine from spinning, thereby containing the oil within the engine components and avoiding immediate loss.

The other options suggest various levels of Ng that imply engine operation, which could lead to scenarios where oil is susceptible to being displaced or lost if not managed properly. When Ng is stabilized and operational, there are risks of oil loss depending on various system pressures and temperatures, hence the emphasis on ensuring a lower Ng to maintain containment.