FAA Commercial Pilot Airplane Knowledge Test Practice Test
The FAA Commercial Pilot Airplane Knowledge Test (CAX) covers aeronautical knowledge used to operate airplanes commercially. This practice page samples decisions involving aircraft performance, weather hazards, airport light signals, engine indications, propeller controls, aerodynamic effects, and coordinated turns. These concepts connect flight planning and aircraft handling with safe responses to changing conditions.
Exam overview
About the FAA Commercial Pilot Airplane Knowledge Test Exam
Commercial airplane operations require pilots to interpret aircraft data and apply it to specific flight conditions. Performance planning involves using the POH with relevant operating conditions to estimate takeoff distance. Aerodynamic knowledge helps explain how extended landing gear affects handling, while coordination skills support balanced turns. Pilots also need to recognize hazards such as developing thunderstorms and instrument conditions in an airplane not approved for those operations. The question bank includes operational judgment involving tower and ground-vehicle light signals, abnormal engine indications such as rough running with low fuel pressure, and the controls used to manage a constant-speed propeller. These examples emphasize translating observations into appropriate actions rather than recalling isolated terms.
Sample Practice Questions
Review a selection from this exam's published US Practice Tests practice bank.
An airplane's landing gear is extended, and the pilot notices a change in handling during a descent. Which general aerodynamic effect is associated with extended landing gear?
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Correct answer: AExtended landing gear generally adds parasite drag. The magnitude and handling effects depend on the airplane, but gear extension does not eliminate induced drag, guarantee increased lift, or prevent a stall.
A pilot uses an aircraft's POH to determine the takeoff distance required for a planned departure. Which practice makes the performance estimate most useful?
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Correct answer: APerformance charts are based on stated assumptions and procedures. The pilot should use the correct chart, follow its instructions, and account for actual conditions such as weight, temperature, pressure altitude, wind, and runway characteristics where the POH directs.
A pilot encounters a developing thunderstorm near the planned route. Which action is the safest general strategy?
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Correct answer: BThunderstorms can produce severe turbulence, hail, lightning, strong updrafts and downdrafts, and rapidly changing conditions. The safest general strategy is to avoid them with ample lateral separation; attempting to fly beneath, through, or over a storm can be hazardous.
A pilot is approaching a runway and sees a ground vehicle displaying an illuminated red signal directed toward the airplane. What should the pilot do?
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Correct answer: BAn illuminated red signal directed at an aircraft on the ground means stop. The pilot should remain stopped until receiving an appropriate signal or instruction to proceed.
During cruise, the engine begins running roughly and the airplane's fuel pressure drops below its normal range. What should the pilot do first?
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Correct answer: ARough operation accompanied by low fuel pressure may indicate a fuel-supply problem. The pilot should promptly use the aircraft-specific checklist and check appropriate fuel-system controls and indications. The precise steps vary by airplane, so the checklist governs.
A pilot sees a steady red light from the control tower while the airplane is on the ground. What does the signal mean?
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Correct answer: BA steady red light signal directed to an aircraft on the ground means stop. The pilot should remain stopped until receiving a signal authorizing movement.
A pilot is preparing to fly through a cloud layer in an airplane not approved for instrument flight. What is the most important reason to avoid entering the cloud?
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Correct answer: BIn cloud, outside visual references such as the natural horizon may be lost. A pilot without the required instrument qualifications, aircraft capability, and clearance should avoid inadvertent instrument conditions because spatial disorientation can develop quickly.
How to use this practice test
Access is free. A session presents up to 20 random questions from the 50-question CAX practice bank, then shows your results. Use missed or uncertain items to identify concepts to revisit, such as POH performance calculations, light-gun signals, engine indications, or coordinated-flight control inputs.
Preparation tips
- Work through POH takeoff-performance examples, accounting for the conditions specified in the performance data and checking that the selected figures match the planned operation.
- Review airport light-gun signal meanings separately for aircraft on the ground and aircraft in flight, including signals directed at an airplane by a ground vehicle.
- For abnormal engine indications, practice identifying the immediate concern in combined cues such as rough running and low fuel pressure, then selecting the applicable aircraft procedure.
- Compare the roles of the propeller control and throttle when managing a constant-speed propeller, and stay within the aircraft's approved operating range.
- Practice recognizing thunderstorm and cloud-entry hazards, and connect ball displacement in a turn with the rudder input used to restore coordination.