If a new safety belt is to be installed in an aircraft, it must conform to the strength requirements in which document?

The correct answer is based on the fact that TSO C22 specifically pertains to the design, construction, and testing of safety belts and harnesses used in aircraft. This TSO (Technical Standard Order) outlines the minimum performance standards for safety belts to ensure they can withstand the forces encountered during turbulence or an emergency landing, thus ensuring passenger safety.

Choosing options other than TSO C22 would not align with the established requirements for safety belts as these other TSOs are related to different components or functions within an aircraft. This highlights the importance of knowing the specific documents that apply to particular aircraft safety equipment. Familiarity with TSO C22 ensures that any safety belt installed in an aircraft meets the necessary strength and safety standards mandated by aviation authorities.