Free PPL aircraft general knowledge 020 questions: 10 with answers
10 aircraft general knowledge questions from the PPL bank of ForAllPilots, with no account and no sign-up. Answer in your head, then open the answer: the right letter and its explanation are under each question. The full bank has 530 questions for this subject.
The 10 questions
Question 1 · 1 Airframe and structure
The role of the elevator trim is to cancel out:
- Athe deflection of the elevator control.
- Bthe constant force on the elevator control surface.
- Cthe drag of the aircraft in a turn.
- Dthe variations in angle of attack experienced.
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Answer: B. the constant force on the elevator control surface.
The elevator is there to change the flight path in the vertical plane, certainly, but also to maintain the aircraft's angle of attack as desired. However, the position of the elevator required to fulfill this role depends on the aircraft's speed, weight, and center of gravity position. The trim is there to hold the elevator in the position where it fulfills this role. Remember, the intelligent pilot avoids unnecessary effort: they trim their aircraft.
Question 2 · 2 Systems
The role of the oleo strut of the landing gear is to:
- Areduce the aircraft's weight.
- Babsorb the energy of impacts upon landing.
- Ccool the brakes.
- Dincrease taxiing speed.
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Answer: B. absorb the energy of impacts upon landing.
The oleo strut absorbs and dissipates the vertical kinetic energy upon ground contact, reducing the forces transmitted to the structure.
Question 3 · 3 Electrics
The power supply source for the spark plugs is:
- Athe magneto.
- Bthe battery.
- Cthe alternator.
- Dthe generator.
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Answer: A. the magneto.
As the engine turns, it drives the magnetos, which are a type of generator, and which supply current to the spark plugs.
Question 4 · 4 Piston engines and propellers
With the ignition key set to OFF, the engine continues to run smoothly. You conclude that:
- Athe primary windings of the magnetos are grounded.
- Bthe engine is experiencing pre-ignition.
- Cthe ground wire of the magnetos is broken.
- Dthe mixture is too lean.
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Answer: C. the ground wire of the magnetos is broken.
To stop a magneto, its primary winding must be grounded. If the wire is broken, that magneto can no longer be grounded, and therefore the engine can no longer be stopped.
Question 5 · 4 Piston engines and propellers
On a piston engine, the altitude mixture control allows:
- Aincreasing the fuel/air mixture ratio as altitude increases.
- Bdecreasing the fuel/air mixture ratio as altitude decreases.
- Censuring a constant pressure of the mixture introduced into the cylinders at all altitudes.
- Dmaintaining the fuel/air mixture ratio constant regardless of altitude.
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Answer: D. maintaining the fuel/air mixture ratio constant regardless of altitude.
What is called the altitude mixture control is the mixture lever, which is used to adjust the richness of the mixture, that is, to keep the mixture ratio roughly constant as altitude changes.
Question 6 · 4 Piston engines and propellers
An important characteristic of the fixed-pitch propeller is:
- Aits rotation speed being too fast.
- Bits constant rotation speed.
- Cits rotation speed being too slow.
- Dits efficiency varying depending on the flight phase.
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Answer: D. its efficiency varying depending on the flight phase.
Like any airfoil, a propeller has an optimal angle of attack. The fixed-pitch propeller's angle of attack varies depending on engine rpm and aircraft speed. Optimal efficiency will therefore very rarely (if ever) be achieved.
Question 7 · 5 Instrumentation
While taxiing, you turn right:
- Athe turn indicator needle moves left and the ball moves right.
- Bthe turn indicator needle moves right and the ball moves left.
- Cthe turn indicator needle and the ball move left.
- Dthe turn indicator needle and the ball move right.
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Answer: B. the turn indicator needle moves right and the ball moves left.
When taxiing in a right turn, the turn indicator needle shows the direction of rotation, i.e. to the right. The ball, subject to centrifugal force with no bank to compensate for it, moves towards the outside of the turn, to the left.
Question 8 · 5 Instrumentation
The static port is blocked. What is the effect on the vertical speed indicator (VSI)?
- AIt permanently indicates zero, regardless of the actual flight path.
- BIt remains perfectly accurate.
- CIt indicates a constant climb.
- DIt indicates a constant descent.
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Answer: A. It permanently indicates zero, regardless of the actual flight path.
The VSI measures the change in static pressure over time; a blocked static port freezes this pressure, so the VSI remains stuck at zero.
Question 9 · 5 Instrumentation
The airspeed indicator measures:
- Aground speed.
- Bdynamic pressure, converted into indicated airspeed (IAS).
- Cpressure altitude.
- Dvertical speed.
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Answer: B. dynamic pressure, converted into indicated airspeed (IAS).
The airspeed indicator compares total pressure (Pitot) to static pressure; this difference, the dynamic pressure, is converted into indicated airspeed (IAS).
Question 10 · 6 Communication and alerting
By selecting the "ALT" function on a transponder:
- Ait transmits pressure altitude.
- Bit transmits the aircraft identification.
- Cit transmits the speed.
- Dit transmits the height relative to the transition level.
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Answer: A. it transmits pressure altitude.
In addition to the code, a mode C transponder transmits pressure altitude, i.e., your height above the 1013 hPa surface.
Each answer was checked again before publication; like every explanation on the site, these may contain errors. Some explanations were rewritten for this page, sometimes with the help of an AI. Spotted a mistake? Write to us at contact@forallpilots.com.
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