Which regulation mandates the use of seat belts for passengers?

The regulation that mandates the use of seat belts for passengers is FAR 91.107. This regulation specifically outlines the requirement for each passenger on an aircraft to be properly secured in a seat belt during takeoff, landing, and whenever instructed by the pilot. This is crucial for ensuring passenger safety, as seat belts significantly reduce the risk of injury during turbulence or in the event of an emergency.

FAR 91.215 pertains to the use of transponders and does not address passenger safety equipment. FAR 91.13 relates to careless or reckless operation of an aircraft, focusing on the pilot's responsibilities and conduct during flight operations. FAR 61.53 deals with the duties and limitations for pilots who may not operate an aircraft when they are not fit to do so, which is unrelated to the use of seat belts in the passenger cabin. Thus, FAR 91.107 is the appropriate regulation concerning the securement of passengers with seat belts.