- The CAX has 105 total questions (100 scored, 5 unscored) in 2 hours 30 minutes; 70% passes.
- The test costs $175 plus tax through PSI and is built from FAA-S-ACS-7B, effective May 31, 2024.
- You must be 16 to sit the knowledge test but 18 to receive the certificate, plus 250 Part 61 flight hours.
- A passing knowledge-test report stays valid for 24 calendar months before your practical test.
CAX Exam Snapshot: The Numbers You Need
Before you memorize a single V-speed or weather symbol, get the mechanics of the Commercial Pilot Airplane knowledge test (CAX) locked into memory. This is the one-page version - the numbers that decide how you schedule, how you budget, and how you pace yourself during the exam.
- Administrator: FAA, delivered through PSI Services LLC testing centers.
- Fee: $175 plus applicable tax per sitting.
- Question count: 105 total questions - 100 scored, 5 unscored validation questions you cannot identify during the test.
- Time allowed: 2 hours 30 minutes.
- Passing score: 70%.
- Current standard: FAA-S-ACS-7B, effective May 31, 2024.
For a deeper breakdown of exactly what that 70% threshold means in raw question terms, see CPL Passing Score 2026: Exactly What You Need to Pass. If you want the full cost picture - knowledge test plus checkride plus training - check CPL Certification Cost 2026: Complete Pricing Breakdown.
Eligibility and Registration Mechanics
The CPL has two separate age gates, and mixing them up trips up more applicants than you'd expect.
- To sit the knowledge test: you must be at least 16 years old and present an accepted ground-school completion document or an instructor endorsement.
- To receive the certificate: you must be at least 18, demonstrate English proficiency, hold at least a private pilot certificate, complete required endorsements, meet aeronautical experience requirements, and pass a practical test.
- Flight hours: Part 61 airplane applicants generally need 250 flight hours.
This layered structure means you can - and often should - knock out the knowledge test well before you finish building hours toward the checkride. For the complete eligibility breakdown, including how endorsements and experience combine, read CPL Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Key Takeaway
Book your PSI testing slot as soon as your ground-school endorsement is signed. Your passing report stays valid for 24 calendar months before the practical test, so there's no rush penalty for testing early relative to your flight-hour progress.
The 12 Domains: One-Line Summaries
The ACS organizes the CAX into twelve content areas. Here's the one-line version of each - enough to jog your memory the morning of the test, but not a substitute for full review. For the expanded walkthrough of every domain with sample topics, see CPL Exam Domains 2026: Complete Guide to All 12 Content Areas.
| Domain | One-Line Summary |
|---|---|
| 1. Federal Aviation Regulations | Part 61/91/119/135 privileges, limitations, and duty rules |
| 2. Aerodynamics and Principles of Flight | Lift, drag, stability, load factor, and stall behavior at commercial maneuvering speeds |
| 3. Aircraft Systems and Flight Instruments | Powerplant, electrical, pitot-static, and gyroscopic instrument logic |
| 4. Weight and Balance | CG computations, loading graphs, and envelope limits |
| 5. Aircraft Performance and Limitations | Density altitude, takeoff/landing charts, and cruise performance |
| 6. Weather Theory | Fronts, stability, icing, turbulence, and thunderstorm hazards |
| 7. Weather Reports and Forecasts | METAR, TAF, prog charts, and AIRMET/SIGMET interpretation |
| 8. Navigation and Flight Planning | Cross-country planning, fuel reserves, and dead reckoning with electronic aids |
| 9. Airspace Classes and Requirements | Class A through G, special use airspace, and entry requirements |
| 10. Airport Operations and Procedures | Markings, lighting, traffic patterns, and towered/non-towered communication |
| 11. Aeromedical Factors | Hypoxia, spatial disorientation, fatigue, and physiological limits |
| 12. Aeronautical Decision Making | Risk management, single-pilot resource management, and commercial-operations judgment calls |
High-Yield Facts by Domain
Not all twelve domains carry equal weight in day-to-day study time. These four consistently cause the most missed questions and deserve extra attention beyond a quick skim.
Domain 4: Weight and Balance
Commercial-level weight and balance problems go beyond private-pilot arithmetic - expect loading graphs, moment envelopes, and shifting-cargo scenarios.
- Practice plotting CG on both tabular and graphical charts, not just one method
Domain 5: Aircraft Performance and Limitations
Density altitude and runway performance charts appear repeatedly, often with interpolation required between chart lines.
- Drill interpolation on takeoff/landing distance charts until it's automatic
Domain 7: Weather Reports and Forecasts
Decoding raw METAR and TAF strings under time pressure is a common bottleneck, especially with less-common remarks codes.
- Memorize the standard METAR field order so decoding becomes pattern recognition
Domain 1: Federal Aviation Regulations
Commercial-specific regulatory distinctions - carrying passengers/property for compensation, Part 119 boundaries, and currency requirements - go beyond what private pilots memorized.
- Focus on where commercial privileges diverge from private pilot limitations
If you're unsure how these domains compare in difficulty or how test-writers weight them, How Hard Is the CPL Exam? Complete Difficulty Guide 2026 breaks down the difficulty curve domain by domain. And if you want to benchmark your own prep against how other candidates perform, CPL Pass Rate 2026: What the Data Shows puts the numbers in context.
Question Format and Test-Day Tactics
Every CAX question is multiple choice with three answer options. With 105 questions in 150 minutes, you have roughly 85 seconds per question on average - but scored and unscored questions are mixed together and indistinguishable, so treat every question as if it counts.
- Flag and move on: PSI's interface allows you to mark questions for review; don't let one chart problem eat ten minutes.
- Use provided references: Figures, charts, and legends are supplied on-screen or in a booklet - know how to navigate them quickly before test day.
- Watch for "least/most" wording: Many wrong answers are correct facts answering the wrong question - read the call of the question twice.
- Budget review time: Leave the last 15-20 minutes to revisit flagged items rather than rushing through new material at the end.
Final-Week Review Schedule
A generic weekly study template doesn't map well onto CPL prep because the domains carry uneven weight and different failure patterns. Here's a compressed final-week sequence built specifically around the domains that cause the most last-minute panic.
Charts and Numbers
- Weight and Balance (Domain 4) and Aircraft Performance and Limitations (Domain 5) - redo chart problems from scratch, timed
Weather Fluency
- Weather Theory (Domain 6) and Weather Reports and Forecasts (Domain 7) - decode fresh METAR/TAF samples daily
Rules and Airspace
- Federal Aviation Regulations (Domain 1) and Airspace Classes and Requirements (Domain 9) - focus on commercial-specific distinctions
Full Simulation
- Take full-length timed practice sets covering all 12 domains; review every miss the same day
For a longer-horizon version of this plan that starts months out rather than one week, see CPL Study Guide 2026: How to Pass on Your First Attempt. Running full-length timed sets on our practice test platform is the fastest way to simulate the real 150-minute, 105-question pressure before you sit the actual PSI exam.
After the Test: Validity and Next Steps
Passing the CAX is a milestone, not the finish line. Your passing knowledge-test report is generally valid for 24 calendar months before the practical test, so plan your flight training and checkride timeline around that window. Exercising commercial pilot privileges after certification also stays subject to flight-review, recency, and medical requirements - the knowledge test doesn't exempt you from those ongoing obligations.
Once certificated, many pilots ask what doors actually open. If you're weighing the investment against career outcomes, CPL Salary Guide 2026: Complete Earnings Analysis and Is the CPL Certification Worth It? Complete ROI Analysis 2026 lay out the return side of the equation, while CPL Jobs covers the roles a Commercial Pilot Certificate actually qualifies you for - banner towing, aerial survey, charter, and flight instruction pathways among them.
If any of the terminology in this cheat sheet still feels unfamiliar, start with the fundamentals: What Is CPL?, CPL Meaning, and What Does CPL Stand For? all cover the baseline definitions this article assumes you already know.
Key Takeaway
Print or save this page as a literal one-pager for your car ride to the PSI testing center - it covers the fee, format, timing, and domain list you'll want fresh in mind minutes before check-in.
FAQ
The CAX contains 105 total questions: 100 scored multiple-choice questions plus 5 unscored validation questions mixed in without any visible labeling.
The CAX fee is $175 plus applicable tax, paid through PSI Services LLC when you schedule your test.
A passing knowledge-test report is generally valid for 24 calendar months before you must complete the practical test.
Yes. Applicants must be at least 16 with an accepted ground-school completion document or instructor endorsement to sit the knowledge test, though the certificate itself isn't issued until age 18.
The CAX is built from FAA-S-ACS-7B, effective May 31, 2024, which organizes content into the 12 domains covered in this cheat sheet.
For scheduling windows and how far ahead to book your PSI slot relative to your ground-school completion, see CPL Exam Dates 2026: Testing Windows, Deadlines & Scheduling. And when you're ready to test your recall against realistic, timed questions across all 12 domains, head back to the main CPL practice test hub to start a full session.