What is the maximum altitude for operation without oxygen in the T-6?

The maximum altitude for operation without oxygen in the T-6 is indeed 10,000 feet MSL. This limit is established to ensure the safety and effectiveness of flight operations. Above this altitude, the risk of hypoxia increases significantly due to reduced partial pressure of oxygen available for breathing. The decision to set this limit is based on physiological factors and the need to maintain cognitive function and motor skills during flight. Therefore, pilots are required to use supplemental oxygen when operating above this altitude to help mitigate the risks associated with low oxygen levels in the atmosphere.