The Airmen Certification Standards, commonly known at the “ACS” are a series of documents that define how testing for pilot certificates and ratings is conducted. There are separate documents for the various certificates, ratings and categories of aircraft for which a pilot can be qualified. For example, the first ACS that most pilots will encounter is known as “Private Pilot – Airplane: Airman Certification Standards.”
Within the Private Pilot ACS are standards for classes of aircraft such Airplane Single Engine Land (ASEL), Airplane Single Engine Sea (ASES), Airplane Multi Engine Land (AMEL) and Airplane Mult Engine Sea (AMES).
The ACS system started in 2011 as an effort to modernize the airmen knowledge tests, which had become larded with outdated questions. The ACS evolved into a replacement for the previous testing standards, which were known as Practical Testing Standards, or “PTS.”
By combining standards for the knowledge and practical portions of airmen testing into a single document, the FAA was hoping to create a more integrated and systematic approach to airman certification.
The ACS is broken into chapters such as Preflight Preparation, Preflight Procedures, Airport Operations, Takeoff, Landings and Go-Arounds, Emergency Operations and so on, depending on which the certificate or rating being tested for. Each chapter is separated into tasks to be evaluated. The Preflight Preparation chapter of the Private Pilot ACS for example starts with the task Pilot Qualifications and proceeds through other topics such as Airworthiness Requirements, Weather Information, Cross-Country Flight Planning and so on.
Each task consists of References pointing to FAA publications specifying how tasks are to be performed, and Objectives in the categories of Knowledge, Risk Management, and Skills.
Each skill to be demonstrated by the applicant specifies performance standards. The performance standard for a private pilot landing requires “Touch down at a proper pitch attitude, within 400 feet beyond or on the specified point, with no side drift, and with the airplane’s longitudinal axis aligned with and over the runway center/landing path.”
The logic behind the ACS is to make the certification process more objective, and less subject to examiner whim by defining the required knowledge and specifying skill performance standards.
Often overlooked in the ACS is the material in the front and back of the documents. There you will find information on how to use the ACS and how exams are to be conducted. There is also a handy checklist for what to bring with you to an exam as well as tables for what tasks are to be performed based on ratings sought or held.