Pilot Your Dreams: Conquer the FAA Ground School Exam 2025!

Passengers can be advised to unfasten their safety belts at cruising altitude when the seatbelt sign is off. This is the standard procedure, as it indicates that the aircraft is in a stable flight phase where it is safe for passengers to move about the cabin.

Typically, the seatbelt sign is turned off once the aircraft reaches cruising altitude and the pilots determine that the flight conditions are calm and safe. It allows for better passenger comfort, as it gives them the freedom to get up, use the restroom, or move around the cabin.

While flight attendants are responsible for ensuring the safety and comfort of passengers, advising them to unfasten their seatbelts is related to aircraft conditions rather than the presence or instructions of flight attendants. Therefore, passenger safety would not depend solely on attendants' instructions, which is why the other options don't adequately capture the correct context for when passengers can safely unfasten their safety belts. The aircraft being on the ground or during ascent would not be appropriate times for this guidance since safety protocols require that seatbelts remain fastened during those phases of flight when conditions may be less stable.