Which statement is true regarding taxi operations?

The statement that both pilots must be task free when crossing runways is correct because runway incursions pose significant safety risks during taxi operations. When an aircraft is crossing a runway, it is critical for both pilots to be alert and focused on the task at hand, ensuring that they are fully aware of potential conflicting traffic and following air traffic control instructions. This joint focus enhances communication and decision-making, leading to safer taxi operations.

In contrast, while it may sometimes be acceptable for only one pilot to manage taxi operations, especially in single-pilot environments or with reduced crew, having both actively engaged during critical phases such as runway crossings maximizes safety. The other statements do not align with standard aviation procedures and regulations, which emphasize the need for diligence and teamwork during high-risk maneuvers like crossing runways and navigating busy airport environments. Additionally, while airport diagrams are extremely helpful and typically recommended for effective situational awareness during taxi operations, they are not technically optional in practical terms. Their use is critical for ensuring pilots can navigate safely and effectively.