Operations and requirements for airliners fall under which FAR part?

The operations and requirements for airliners are primarily governed by FAR Part 121. This section of the Federal Aviation Regulations deals specifically with the certification and operation of scheduled air carriers, which includes airlines conducting commercial passenger and freight flights. It establishes safety standards that airlines must adhere to, including maintenance, operations, crew qualifications, and safety procedures.

FAR Part 121 outlines the rules for larger commercial aircraft and those that operate on scheduled routes, ensuring that such operations are consistent and standardized across the industry in order to enhance safety and reliability. This regulatory framework is crucial for ensuring that air transportation remains safe and efficient, and it encompasses a wide range of operational aspects necessary for airliners.

In contrast, the other parts mentioned pertain to different types of operations. For instance, FAR Part 133 deals with rotorcraft external load operations, Part 135 covers commuter and on-demand operations for smaller aircraft, and Part 141 relates to pilot schools. These distinctions clarify why FAR Part 121 is the correct answer when it comes to airliner operations.