Airmen Certification Standards are detailed criteria for written exams, oral and practical exams, and everything you must know and be able to perform to earn the desired certificate/license. It also serves as a reference for instructors, examiners, and applicants during training and evaluation. There is a specific ACS for each rating so you must ensure that you utilize the proper document for your desired rating. You can look for a specific ACS through the following FAA link below.