- CAX Test Overview: What You're Actually Signing Up For
- The 12 Domains and Where They Bite
- Scheduling, Fees, and Endorsement Paperwork
- A Domain-Sequenced Study Timeline
- Where First-Time Test Takers Lose Points
- After You Pass: Validity, Experience, and the Practical Test
- Who Actually Cares About This Certificate
- Frequently Asked Questions
- The CAX has 100 scored questions plus 5 unscored ones, 150 minutes, 70% to pass.
- PSI Services LLC administers the test for $175 plus tax under FAA-S-ACS-7B.
- 2025's national pass rate was 99.17% across 20,530 tests - preparation matters more than luck.
- Part 61 airplane applicants generally need 250 flight hours before certificate issuance.
CAX Test Overview: What You're Actually Signing Up For
The Commercial Pilot Airplane knowledge test - everyone in the training world just calls it the CAX - is a computer-based exam administered through PSI Services LLC on behalf of the FAA. You'll sit for 105 total multiple-choice questions: 100 that count toward your score and 5 unscored "validation" items the FAA uses to test future questions. You get 2 hours and 30 minutes to finish, and you need 70% correct to pass. The current standard governing the question pool is FAA-S-ACS-7B, effective since May 31, 2024, which replaced the older PTS-based approach with a more explicit list of knowledge, risk management, and skill elements.
This isn't a certificate test by itself - it's the knowledge component that clears you to move toward the practical (checkride) portion. If you want the full picture of how this knowledge test fits into the larger certification path, our CPL Requirements 2026 guide lays out eligibility and prerequisites in detail, and the ../ practice platform lets you simulate the actual test format before test day.
The 12 Domains and Where They Bite
The CAX question bank is organized around twelve knowledge domains. Some domains are dense with regulatory memorization; others test your ability to interpret charts, graphs, and performance tables under time pressure. Knowing which domain you're weak in - not just "studying everything" - is what separates efficient prep from panic-cramming the week before your test date.
Domain 1: Federal Aviation Regulations
Commercial operating rules under Part 61 and Part 91 dominate here, including currency, carriage-for-hire limitations, and pilot-in-command requirements specific to commercial privileges.
- Know the differences between private and commercial operating limitations
- Memorize recent flight experience and logging requirements
Domain 2: Aerodynamics and Principles of Flight
Expect questions on load factors, stalls in various configurations, and how commercial-category maneuvers stress airframes differently than private-level flying.
- Understand load factor charts and bank-angle relationships
- Review high-performance stall and spin aerodynamics
Domain 3: Aircraft Systems and Flight Instruments
Turbocharging, retractable gear systems, constant-speed propellers, and pitot-static instrument errors show up frequently since commercial training often involves more complex aircraft.
- Study constant-speed prop and turbocharger operating logic
- Know pitot-static and gyroscopic instrument failure modes
Domain 4: Weight and Balance
This domain is calculation-heavy. Expect to compute CG shifts, use loading graphs, and determine whether a configuration is within envelope limits.
- Practice moment and arm calculations until they're automatic
- Learn to read loading graphs quickly, not just formulas
Domain 5: Aircraft Performance and Limitations
Density altitude, takeoff/landing distance charts, and climb performance tables are tested with real numbers you must interpolate.
- Practice chart interpolation under a timer
- Understand how temperature and altitude interact with performance
Domain 6: Weather Theory
Stability, frontal behavior, icing conditions, and thunderstorm development form the theoretical backbone tested here.
- Review air mass stability and frontal passage effects
- Study icing types and the conditions that produce them
Domain 7: Weather Reports and Forecasts
METARs, TAFs, and other aviation weather products require fast, accurate decoding - this domain rewards repetition over theory.
- Decode METAR/TAF strings until it's second nature
- Practice reading winds-aloft and area forecast products
Domain 8: Navigation and Flight Planning
Cross-country planning, fuel reserves, and navigation log construction for commercial operations are tested with scenario-based questions.
- Build full flight plans by hand, not just with an app
- Know fuel reserve requirements for commercial operations
Domain 9: Airspace Classes and Requirements
Class B through G airspace, special use airspace, and entry requirements are tested with chart-reading questions.
- Memorize entry requirements for each airspace class
- Practice identifying special use airspace on sectional excerpts
Domain 10: Airport Operations and Procedures
Runway markings, lighting systems, and traffic pattern procedures at towered and non-towered fields appear frequently.
- Review runway/taxiway signage and lighting systems
- Know right-of-way and pattern entry rules cold
Domain 11: Aeromedical Factors
Hypoxia, spatial disorientation, and physiological stressors specific to sustained commercial flying are the focus.
- Study hypoxia symptoms and time of useful consciousness
- Review vestibular illusions during instrument conditions
Domain 12: Aeronautical Decision Making
Scenario-based judgment questions test risk management frameworks rather than pure recall.
- Practice applying risk-management models to scenario questions
- Recognize hazardous attitudes described in question stems
For a deeper walkthrough of each area with sample question styles, see our CPL Exam Domains 2026 guide. If you're still deciding whether the workload is proportionate to the difficulty, How Hard Is the CPL Exam? breaks down the difficulty curve domain by domain.
Scheduling, Fees, and Endorsement Paperwork
Before you can even sit for the CAX, you need to be at least 16 years old and present an accepted ground-school completion document or an instructor endorsement confirming you're prepared for the test. The test itself costs $175 plus applicable tax, paid directly through PSI when you schedule.
Certificate issuance is a separate bar entirely - you must be 18, demonstrate English proficiency, already hold at least a private pilot certificate, complete the required endorsements, log the necessary aeronautical experience, and pass a practical test. Part 61 airplane applicants generally need 250 flight hours logged before that certificate can be issued.
Key Takeaway
Don't schedule your CAX the week your ground school ends. Book it once your instructor confirms you're ready and after you've run at least one full-length timed practice session on ../ to confirm your pacing across all 105 questions.
For a full cost accounting beyond just the $175 exam fee - including training, checkride, and materials - read CPL Certification Cost 2026. And if you want exact scoring mechanics spelled out, including how the 70% threshold interacts with the 100 scored questions, check CPL Passing Score 2026.
A Domain-Sequenced Study Timeline
Generic study advice - spaced repetition, timed drills, weekly review cycles - only helps if it's mapped to the CAX's actual domain weighting. Below is a sequencing approach built around tackling calculation-heavy domains early (while your brain has bandwidth) and saving fast-recall domains for the final week before your test date.
Regulations and Aerodynamics Foundation
- Work through Domain 1 (Federal Aviation Regulations) with a focus on commercial-specific Part 61/91 differences
- Pair it with Domain 2 (Aerodynamics and Principles of Flight) since load factor concepts reappear in regulation-based scenario questions
Systems and Calculations
- Drill Domain 3 (Aircraft Systems and Flight Instruments) alongside Domain 4 (Weight and Balance) and Domain 5 (Aircraft Performance and Limitations)
- These three domains reward repetition on charts and formulas - do timed problem sets daily
Weather and Navigation
- Cover Domain 6 (Weather Theory) and Domain 7 (Weather Reports and Forecasts) together since they build on each other
- Follow with Domain 8 (Navigation and Flight Planning) using full cross-country planning exercises
Airspace, Airports, and Human Factors
- Finish with Domain 9 (Airspace Classes and Requirements), Domain 10 (Airport Operations and Procedures), Domain 11 (Aeromedical Factors), and Domain 12 (Aeronautical Decision Making)
- Run at least two full 105-question timed simulations before test day
This isn't the only valid order, but it front-loads content that benefits from deep, slow thinking and ends with material that's mostly pattern recognition - which holds up better under exam-day fatigue. If you'd rather follow a more general master plan first, start with our CPL Study Guide 2026 and layer this domain sequencing on top of it.
Where First-Time Test Takers Lose Points
Even with a near-99% pass rate, missed points cluster in predictable places. The domains that combine numeric precision with time pressure - Weight and Balance, Aircraft Performance and Limitations, and Weather Reports and Forecasts - are where candidates most often burn extra minutes or second-guess a correct answer.
| Domain | Common Struggle | Fix |
|---|---|---|
| Weight and Balance | Misreading loading graphs under time pressure | Practice graph-based problems, not just formulas |
| Aircraft Performance | Interpolating between chart values incorrectly | Drill interpolation with a timer daily |
| Weather Reports/Forecasts | Slow METAR/TAF decoding costs exam time | Decode products until it's automatic, not analytical |
| Aeronautical Decision Making | Overthinking scenario-based judgment questions | Apply a consistent risk-management framework each time |
None of this requires new content knowledge - it requires converting slow, deliberate calculation into fast pattern recognition. That's exactly what repeated timed practice on a question bank modeled after the real CAX format does better than passive reading. Our CPL Pass Rate 2026 breakdown digs further into where the national numbers suggest candidates lose the most ground.
After You Pass: Validity, Experience, and the Practical Test
Passing the CAX gets you a knowledge test report, which is generally valid for 24 calendar months before you sit for the practical test. That's a real deadline - if your flight training stretches longer than two years, you may need to retake the knowledge test before your checkride.
Passing the knowledge test doesn't make you certificated. You still need the 250 flight hours (Part 61, airplane), the required instructor endorsements, English proficiency, and a completed practical test with an examiner. Once issued, exercising commercial privileges stays subject to flight-review, recency, and medical requirements - the certificate isn't a permanent unlock, it's an ongoing responsibility.
For the exact eligibility chain from private pilot certificate through commercial issuance, our CPL Requirements 2026 article maps every prerequisite in sequence. If you're unclear on what the certificate itself even represents before you invest the hours, What Is CPL? and CPL Meaning cover the basics plainly.
Who Actually Cares About This Certificate
The CPL is the credential that legally allows you to be paid for flying - it's the line between flying as a hobby and flying as a job. Regional airlines, charter operators, banner-tow and aerial survey companies, flight schools hiring instructors (with the appropriate add-on), and corporate flight departments all require it as a baseline. None of them care how you scored on the CAX beyond pass/fail, but they absolutely care that you hold the certificate and meet the experience minimums behind it.
If you're weighing whether this whole process is worth the time and money before you commit to a ground school, Is the CPL Certification Worth It? runs the numbers, and CPL Salary Guide 2026 covers realistic earnings trajectories after certification. For a look at what actual roles look like once you're certificated, see CPL Jobs.
Key Takeaway
The knowledge test is a gate, not the destination. Treat CAX prep as the first controllable milestone in a longer experience-building process toward certificate issuance and paid flying work.
Whichever stage you're at, running full-length practice sessions on ../ before your scheduled PSI test date is the single most reliable way to convert domain knowledge into exam-day speed.
Frequently Asked Questions
The CAX has 105 total questions: 100 scored multiple-choice items and 5 unscored validation questions used by the FAA for future test development.
The CAX costs $175 plus applicable tax, paid through PSI Services LLC when you schedule your test session.
You need 70% or higher on the 100 scored questions to pass the CAX.
A passing knowledge test report is generally valid for 24 calendar months, during which you must complete the practical test.
No minimum flight hours are required to sit for the knowledge test itself, but you must be at least 16 and have an accepted ground-school completion document or instructor endorsement. Certificate issuance, separately, generally requires 250 flight hours under Part 61 for airplane applicants.