What is the fuel requirement if a second alternate is required?

In the context of flight planning, when a second alternate is required, the fuel calculation must account for several specific criteria to ensure safety and compliance with regulations. The correct choice, which includes fuel to the destination, the furthest alternate, and an additional 45 minutes at cruise, reflects the comprehensive approach necessary for adequate contingency planning.

This option recognizes that pilots must not only reach their primary destination but also have sufficient fuel reserves to divert to the most distant alternate airport, should that become necessary. The inclusion of 45 minutes of fuel at cruise speed is a standard precaution that provides a buffer for unforeseen circumstances, such as unexpected weather changes, airport congestion, or other factors that might delay the aircraft from landing.

This approach ensures that the aircraft has enough resources to handle potential emergencies or diversions, thereby prioritizing safety and regulatory compliance in flight operations. Thus, this choice embodies the best practice in aviation fuel planning for situations where second alternates are mandated.