What does a combined roll and yaw indicator help a pilot understand?

A combined roll and yaw indicator provides critical information about the aircraft's balance and coordination during flight. It visually represents the aircraft's roll attitude and yaw movement, which are essential for maintaining controlled flight and proper aerodynamics. When pilots observe the readings from the indicator, they can assess whether the aircraft is coordinated properly – meaning the ailerons and rudder are working together effectively to maintain straight flight without skidding or slipping.

In practical terms, if the pilot sees the roll indicator deflected without the yaw indicator being aligned, it indicates a potential uncoordinated flight condition, prompting the pilot to correct the inputs accordingly. By addressing any discrepancies between the roll and yaw values, a pilot can ensure that the aircraft remains stable, enhancing safety and performance during maneuvers.

This understanding is vital, especially during turns and maneuvers that involve banking, as it helps in maintaining the aircraft on the intended flight path. The other options focus on aspects like altitude changes, turbulence, and ground speed, which are not the primary functions of a combined roll and yaw indicator.