The FAA Airman Certification Standards (ACS) define exactly what a pilot or aviation mechanic must know, consider, and do to earn an FAA certificate or rating. Developed as an evolution of the old Practical Test Standards (PTS), the ACS integrates knowledge, risk management, and skill elements into a single, unified framework that examiners and applicants both reference during certification testing.
Whether you are a student pilot working toward your Private Pilot Certificate, an experienced aviator pursuing an additional rating, or a maintenance technician seeking an Airframe and Powerplant (A&P) mechanic certificate, the ACS is the authoritative guide to your checkride. Downloading a printable ACS practice test PDF lets you review questions offline, annotate answers, and test yourself in conditions that mirror the actual FAA Knowledge Test environment—no internet connection required.
Aviation mechanic applicants face a particularly broad body of knowledge: from reciprocating and turbine engine theory to airframe structures, hydraulic systems, electrical circuits, avionics, and federal maintenance regulations. A well-structured PDF study guide organizes those topics in alignment with the ACS task codes so every page you study maps directly to an examinable task.
The Airman Certification Standards are organized around three core elements for every task an applicant must demonstrate. Knowledge items cover the factual and procedural understanding an airman must possess—regulations, aircraft systems, meteorology, navigation, and maintenance principles. Risk Management items assess the applicant's ability to identify hazards, evaluate probability and severity, and apply sound aeronautical decision-making (ADM). Skills items define the observable, measurable performance standards the applicant must meet during the practical test.
Each task is assigned an ACS code (for example, PA.I.A.K1 for Private Airplane Area I Task A Knowledge item 1). This coding system lets applicants, instructors, and designated pilot examiners (DPEs) communicate precisely about which specific competency is being evaluated. When you study from an ACS-aligned practice test PDF, every question is traceable to a specific task code, so you can identify and close knowledge gaps methodically.
Mechanics who service and maintain civil aircraft must hold an FAA Mechanic Certificate issued under Title 14 CFR Part 65. There are two ratings: Airframe and Powerplant. Most employers require both, which is why technicians are commonly called A&P mechanics. To qualify for either rating, an applicant must meet one of three paths: 18 months of practical experience for a single rating (30 months for both), graduation from an FAA-approved Aviation Maintenance Technician School (AMTS), or military service in an aviation maintenance role.
Once eligibility is established, the applicant must pass three tests for each rating sought:
Reciprocating Engines. Applicants must understand four-stroke engine theory, carburetion, fuel injection, ignition systems, engine instruments, and troubleshooting procedures. Topics include magneto timing, valve train inspection, oil system maintenance, and engine runup checks.
Turbine Engines. Gas turbine theory covers axial and centrifugal compressors, combustion sections, turbine stages, exhaust systems, and the Brayton cycle. Mechanics must know turbine engine inspections, hot section intervals, Foreign Object Damage (FOD) procedures, and engine trend monitoring.
Airframe Structures. Knowledge areas include sheet metal repair, composite materials, structural stress analysis, riveting techniques, corrosion control, welding fundamentals, and damage classification. Applicants are expected to read and apply aircraft structural repair manuals (SRMs).
Hydraulic Systems. Topics cover hydraulic fluid types, actuators, accumulators, pumps, selector valves, and brake systems. Seals, plumbing standards (MS flareless fittings), and system bleeding procedures are tested under the ACS.
Electrical Systems. Mechanics must understand DC and AC circuits, Ohm's law, battery systems, alternators, generators, wiring standards per AC 43.13-1B, circuit protection devices, and avionics bonding requirements.
Avionics. The ACS addresses VHF communication antennas, navigation receivers (VOR, ILS, GPS/GNSS), transponders, ADS-B Out compliance, and static wicks. EMI shielding, antenna placement, and interference troubleshooting are practical skill areas.
Federal aviation regulations governing maintenance are primarily found in 14 CFR Part 43 (maintenance, preventive maintenance, rebuilding, and alteration), Part 65 (certification of mechanics), and Part 91 (operating rules, owner responsibilities). The ACS tests whether applicants can locate, interpret, and apply these regulations correctly.
Airworthiness Directives (ADs) are legally enforceable rules issued under 14 CFR Part 39 to correct unsafe conditions in aircraft, engines, propellers, or appliances. An A&P mechanic must know how to research applicable ADs using the FAA's AD database, determine compliance status, and document AD compliance in aircraft maintenance records. Recurring ADs require interval tracking; one-time ADs require notation that they have been accomplished.
Proper documentation is as critical as the maintenance itself. Under 14 CFR Part 43, a certificated mechanic must make a maintenance record entry for each inspection or maintenance action that includes: a description of the work, the date it was completed, the aircraft total time in service, the signature and certificate number of the person approving the aircraft for return to service, and the kind of certificate held.
Annual and 100-hour inspection sign-offs require the inspector to state that the aircraft has been inspected and found to be in airworthy condition (or to list discrepancies). These records must be retained with the aircraft. The ACS tests applicants on what constitutes a complete logbook entry and what information must be retained versus what can be discarded.
Every aircraft must be operated within its certified weight and center-of-gravity (CG) envelope. Mechanics are responsible for performing weight-and-balance computations after modifications, repairs that remove or add equipment, or after any major alteration. The ACS covers empty weight CG calculations, moment arm concepts, and the use of weight-and-balance data sheets. An aircraft operated outside its approved CG limits is not airworthy regardless of other maintenance status.
Annual Inspection. Required every 12 calendar months for all aircraft not operated under a progressive inspection program. Must be performed by an FAA-certificated mechanic holding an Inspection Authorization (IA) or by an FAA-certificated repair station. The annual inspection follows a checklist conforming to the manufacturer's maintenance manual and 14 CFR Part 43, Appendix D.
100-Hour Inspection. Required for aircraft operated for hire or flight instruction (given for hire). Functionally equivalent to an annual inspection but may be performed by any A&P mechanic (IA not required for the 100-hour). The 100-hour limit may be exceeded by up to 10 hours to fly to a location where the inspection can be performed, but the next 100-hour limit is calculated from where the previous one was due, not from when it was actually completed.
Progressive Inspection. An alternative to annual/100-hour inspections that spreads the workload into smaller periodic segments. Must be performed under an approved program and administered by an IA or repair station.
Print the PDF double-sided and work through each section without referring to notes first, simulating actual test conditions. Mark questions you are unsure about, complete the entire set, then score your answers before reviewing explanations. This approach reveals which ACS task areas need the most attention before your scheduled Knowledge Test date.
For deeper practice with randomized questions, timed sessions, and instant scoring, visit our full ACS practice tests hub. The online tests draw from the same task areas covered in this PDF and let you filter by subject—General, Airframe, or Powerplant—so you can target the areas where you need the most improvement.