Which document must you have readily accessible while piloting a helicopter?

The requirement to have your license and medical certificate readily accessible while piloting a helicopter is grounded in aviation regulations. The pilot certificate serves as proof that you are legally allowed to operate the aircraft, while the medical certificate verifies that you meet the necessary health standards to ensure safe flight. Both documents must be available either physically or electronically to demonstrate compliance with FAA regulations during any flight operation.

In contrast, while recent logbook entries and a flight instructor's endorsement are important for tracking flight experience and ensuring currency for specific operations, they are not mandated to be readily accessible during flight. The other option concerning tax identification is unrelated to aviation safety or pilot qualifications and thus does not hold relevance while piloting an aircraft.