What is the maximum allowable ground speed for turbulent air penetration?

The maximum allowable ground speed for turbulent air penetration is determined by the aircraft's operational guidelines, particularly to maintain safety and structural integrity during encounters with turbulence. In this case, the correct answer of 280 KIAS aligns with standard operating procedures for managing turbulence.

This maximum ground speed helps to reduce the risk of structural damage to the aircraft that can be exacerbated by excessive speed through turbulent conditions. Operating at or below this threshold ensures that the pilots can effectively maintain control and respond appropriately to sudden changes in air currents, which are common during turbulence.

Other values provided in the options would imply exceeding the recommended speed limits for turbulent air, which can lead to increased passenger discomfort and potential safety issues. Therefore, adhering to the maximum allowable ground speed of 280 KIAS is essential for safe flight operations in turbulent conditions.