Which of the following is NOT a requirement to hold an SCA?

To hold a Sport Pilot Certificate with a Light-Sport Aircraft endorsement, it is crucial to fulfill specific training and certification requirements. The option stating "Completion of a solo cross-country flight" is indeed NOT a requirement. While solo cross-country flights are an important component of the training for a broader pilot certificate or certain endorsements, they are not mandated for specifically holding an SCA.

On the other hand, completing 15 hours of training, obtaining an endorsement from a certified flight instructor, and possessing a student pilot certificate are all essential parts of the process. The requirement ensures that the pilot has received enough instructional time, is qualified through instructor assessment, and has met the legal prerequisites to operate as a pilot in training. Thus, each of these elements plays a vital role in ensuring that the student pilot is well-prepared for solo flying, unlike the specific requirement of a solo cross-country flight, which is not obligatory for holding an SCA.