Which of the following documents is required to be on board prior to flight?

The requirement to have weight and balance data on board prior to flight is critical for ensuring the safety and performance of the aircraft. The weight and balance documentation provides essential information on the aircraft's loaded weight and its center of gravity location, both of which significantly impact its handling characteristics and performance margins.

Correctly calculating weight and balance is vital for safe flight operations as an aircraft that is improperly loaded may stall at a higher airspeed or have diminished control effectiveness, potentially leading to hazardous situations. This document serves to verify that the aircraft is within its specified weight limits and that the distribution of weight does not adversely affect stability during flight.

While other documents may be important in the broader context of flying, such as insurance policies which are crucial for liability, pilot logbooks which track flight experience, and flight planning checklists that aid in pre-flight preparation, they are not legally mandated to be onboard the aircraft during the flight itself as weight and balance data is. For this reason, ensuring that appropriate weight and balance documentation is on board is a regulatory requirement that directly enhances flight safety.