What type of training report is used to document additional training accomplishments?

The correct choice documents additional training accomplishments effectively. AF Form 1522 is specifically designed to record various forms of training completed by personnel, including those that are not part of the standard training curriculum. This form helps to ensure that all relevant training achievements are officially recognized and tracked, allowing for a comprehensive overview of an individual's qualifications and skills.

AF Form 1521, while also related to training, is primarily used for documenting the completion of formal training courses which may not encompass the broader range of additional training sessions that AF Form 1522 covers. Similarly, AF Form 1520 serves a different administrative function, often dealing with training evaluations or assessments, and does not focus exclusively on additional accomplishments. AF Form 1523 might relate to other training activities, but it does not align with the specific purpose of recording additional training accomplishments as defined in the question. Thus, using AF Form 1522 makes it ideal for capturing and recognizing these important supplementary training achievements.