Which regulation outlines solo flight requirements under the SCA?

The regulation that outlines solo flight requirements under the SCA is 14 CFR Part 61. This section of the Code of Federal Regulations specifically deals with pilot certification, including requirements for different types of pilot certificates, and sets out the training and testing necessary for pilots to achieve solo flight privileges.

In Part 61, you'll find detailed information on the training that must be completed before a student pilot can fly solo, including requirements for endorsements from certified instructors. Additionally, this part explains the privileges and limitations placed on student pilots, which directly pertains to the context of solo flying.

The other parts mentioned have different focuses. Part 91 primarily addresses the general operating and flight rules for all pilots, Part 91.151 is related to fuel requirements for flight in general aviation, and Part 141 pertains to flight schools and their training programs. While these regulations are important, they do not specifically outline the solo flight requirements for student pilots under the SCA, making Part 61 the correct reference for the question.