What occurs when there is a loss in engine oil during operation?

When there is a loss of engine oil during operation, one of the critical responses is that the propeller will feather. Feathering the propeller is a process that adjusts the blade angle to minimize drag and optimize performance when the engine is shut down or if it is not producing power. This is particularly important in multi-engine aircraft, where one engine may fail, allowing the pilot to maintain control and reduce drag on the aircraft.

Feathering helps to maintain altitude and glide capability, thus enhancing the safety of the flight despite the engine oil loss. The ability to feather is crucial for maintaining performance in the event of an engine failure or oil loss.

The other options involve effects that are not typically related to the loss of engine oil. An immediate shutdown of the engine may occur, but not in all cases, and it doesn't encompass the feathering action that helps maintain control. The propeller taking off is not a technically plausible scenario, and the landing gear malfunctioning does not directly relate to engine oil loss. Therefore, feathering is the most applicable response to an engine oil loss situation.