What are the indications of mechanical failure in the T-6?

Unusual vibrations and loss of control responsiveness are key indicators of mechanical failure in the T-6. When the aircraft experiences mechanical issues, it often results in abnormal sensations that a pilot can feel, such as vibrations that are out of the ordinary. This could signal problems with the aircraft's systems, such as the engine, control surfaces, or other critical components. Additionally, a loss of control responsiveness can indicate that the aircraft is not performing as expected due to potential mechanical malfunctions. This lack of responsiveness may make it difficult for the pilot to maintain control, which can be a serious safety concern that requires immediate attention.

The other options provide indications that may be related to aircraft performance or operational changes but are not specific indicators of mechanical failure. Increased fuel consumption can occur for various reasons, but it does not directly point to a mechanical issue. The appearance of warning lights may indicate various system alerts, but not all are necessarily indicative of mechanical failures—some may simply be routine alerts. Similarly, altitude fluctuations could result from atmospheric conditions or pilot input rather than a direct mechanical problem.