How long can the oil temperature be at 99-110°C during operation?

The correct duration for which the oil temperature can be safely maintained at 99-110°C during operation is 10 minutes. This limitation is crucial for engine health, as higher oil temperatures can lead to decreased lubrication effectiveness and potentially premature wear or damage to engine components.

The manufacturer specifies this time limit based on the performance characteristics of the oil used in the King Air 350 engines. Exceeding this duration may result in overheating and oil degradation, impacting engine reliability and safety. Knowing and adhering to these operational limits is essential for maintaining optimal engine function and longevity, which is why this specific answer aligns with the operational guidelines for the aircraft.