Which system provides fuel reading in the T-6A when the low fuel warning lights are activated?

The correct answer is that the system providing fuel readings when the low fuel warning lights are activated is the one that uses optical sensors. In the T-6A, optical sensors are employed to determine the fuel quantity in the tanks. These sensors utilize light to measure the level of fuel directly rather than relying on mechanical movement or pressure changes, which can be less accurate or slower to respond.

When the fuel level falls below a certain threshold, the optical sensors prompt the activation of the low fuel warning lights. This method offers a quick and effective means of notifying the pilot regarding fuel status, enabling proactive management of fuel reserves.

Other systems such as mechanical gauges might not provide readings specifically linked to the low fuel warning due to their reliance on moving parts, and digital displays generally present information as interpreted by the sensors rather than generating the data. Pressure sensors, while often used in other applications within an aircraft, do not directly provide the specific fuel readings in response to low fuel alerts in the T-6A.