I85PREP
⌘ K
CAAP CPL Knowledge Exam study materials
CAAP CPL Knowledge Exam study resources

CAAP CPL Knowledge Exam practice questions

One question at a time. Build your CAAP CPL Knowledge Exam understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Air Law and Regulations

Under CARs Part IV, what is the minimum age for a person to be issued a private pilot licence?

  1. 14 years
  2. 17 years Correct answer.
  3. 16 years
  4. 18 years

Explanation

Transport Canada requires an applicant to be at least 17 years of age for the issue of a private pilot licence, although solo flight may begin earlier under a student permit. The 17-year minimum applies at the time the licence is actually issued.

Question 2Air Law and Regulations

Which document must a pilot carry on board an aircraft during flight in Canada?

  1. The aircraft journey log
  2. The pilot licence and medical certificate Correct answer.
  3. The aircraft maintenance manual
  4. The company operations manual

Explanation

CAR 401.03 requires the holder of a licence or permit to carry it, together with the required medical certificate, while exercising the privileges of that licence. The journey log, maintenance manual and operations manual are not documents the pilot must personally carry for every flight.

Question 3Air Law and Regulations

What class of Canadian airspace generally requires an ATC clearance for all IFR and VFR flight?

  1. Class F advisory airspace
  2. Class C airspace Correct answer.
  3. Class G airspace
  4. Class E airspace

Explanation

Class C controlled airspace requires an ATC clearance for both IFR and VFR aircraft, and VFR aircraft must also meet the equipment and communication requirements. This distinguishes it from Class E, where VFR aircraft do not need a clearance, and Class G, which is uncontrolled.

Question 4Air Law and Regulations

When must a pilot file a flight plan or flight itinerary before departing on a cross-country VFR flight?

  1. When the aircraft carries more than four occupants
  2. When the flight will operate beyond 25 nautical miles from the departure aerodrome Correct answer.
  3. Only when flying above 12,500 feet ASL
  4. Only when the flight will enter Class C airspace

Explanation

CAR 602.73 requires a flight plan or itinerary for VFR flights that will be more than 25 nautical miles from the departure aerodrome, or that will operate in designated areas. This ensures search-and-rescue authorities are aware of the flight.

Question 5Air Law and Regulations

What is the standard VFR minimum flight visibility for aircraft operating in Class G airspace at or below 1,000 feet AGL during the day?

  1. Five statute miles
  2. One statute mile
  3. Three statute miles
  4. Two statute miles Correct answer.

Explanation

In Class G airspace at or below 1,000 feet AGL during the day, the minimum flight visibility is two statute miles and the aircraft must remain clear of cloud. Higher minima apply at night and at higher altitudes.

Question 6Air Law and Regulations

What does a steady red light signal directed at an aircraft in flight mean?

  1. Cleared to land
  2. Airport unsafe, do not land
  3. Give way and continue circling Correct answer.
  4. Return for landing

Explanation

A steady red light directed at an aircraft in flight means the aircraft must give way to other traffic and continue circling. A flashing red light means the airport is unsafe and landing is prohibited.

Question 7Air Law and Regulations

Under the CARs, what is the required cruising altitude for VFR flight in the Southern Domestic Airspace when tracking between 0 and 179 degrees magnetic?

  1. Even thousands plus 500 feet Correct answer.
  2. Odd thousands plus 500 feet
  3. Odd thousands only
  4. Even thousands only

Explanation

In the Southern Domestic Airspace, VFR aircraft tracking 0 to 179 degrees magnetic use even thousands plus 500 feet, while tracks from 180 to 359 degrees use odd thousands plus 500 feet. This semicircular rule separates opposing traffic.

Question 8Air Law and Regulations

A pilot holds a private pilot licence and wishes to fly a passenger on a cost-sharing basis. Which condition must be met for the flight to remain lawful?

  1. The passenger must hold a valid medical certificate
  2. The pilot must not advertise the flight to the public Correct answer.
  3. The pilot must hold a commercial pilot licence
  4. The flight must be conducted under an air operator certificate

Explanation

Cost-sharing is permitted for private pilots provided the pilot does not advertise to the public and the costs are shared proportionally among the occupants. It cannot be used to generate profit, which would require a commercial licence.

Question 9Air Law and Regulations

An aircraft is operating in Class C airspace under VFR. Which equipment is required for this flight?

  1. A Mode C transponder and two-way radio Correct answer.
  2. A 406 MHz ELT only
  3. A GNSS receiver only
  4. A Mode A transponder only

Explanation

VFR flight in Class C requires a serviceable two-way radio and a Mode C transponder, along with an ATC clearance. These allow the aircraft to communicate and to be identified and separated by radar.

Question 10Air Law and Regulations

A pilot is planning a flight that will cross into the United States. What document must the pilot ensure is on board to satisfy Canadian requirements for the aircraft?

  1. A pilot operating handbook only
  2. An aircraft bill of sale
  3. A certificate of airworthiness Correct answer.
  4. An insurance binder

Explanation

CAR 605.03 requires that a certificate of airworthiness be carried on board the aircraft during flight. This document confirms the aircraft meets its type design and is maintained in accordance with the regulations.

Question 11Air Law and Regulations

Under CAR 602.19, when must a pilot report a potentially hazardous weather condition to ATC?

  1. Immediately upon encountering it Correct answer.
  2. At the next scheduled position report
  3. Only if requested by ATC
  4. Only after landing

Explanation

Pilots are required to report hazardous weather, such as severe turbulence, icing or wind shear, to ATC as soon as practicable so other aircraft can be warned. Delaying the report reduces its safety value.

Question 12Air Law and Regulations

What is the minimum fuel reserve required for a day VFR flight in a piston-engine aeroplane under CAR 602.88?

  1. 30 minutes Correct answer.
  2. 60 minutes
  3. 45 minutes
  4. 90 minutes

Explanation

Under CAR 602.88, a piston-engine aeroplane on a day VFR flight must carry enough fuel to reach its destination and then fly for at least 30 minutes at normal cruising speed. The corresponding night VFR reserve is 45 minutes.

Question 13Air Law and Regulations

A pilot is flying at 9,500 feet ASL without supplemental oxygen. What is the maximum time allowed above 10,000 feet without oxygen for the crew?

  1. 20 minutes
  2. 30 minutes Correct answer.
  3. 45 minutes
  4. 10 minutes

Explanation

CAR 605.31 permits flight above 10,000 feet without supplemental oxygen for a maximum of 30 minutes for the flight crew. Beyond that, oxygen must be used.

Question 14Air Law and Regulations

An aeroplane is being operated at night in VFR conditions. Which lighting is required on the aircraft?

  1. Landing lights only
  2. Anti-collision lights only
  3. Navigation lights only
  4. Navigation lights and anti-collision lights Correct answer.

Explanation

Night operations require both navigation lights and anti-collision lights to ensure the aircraft is visible to other traffic. These lights allow other pilots to determine the aircraft's position and direction of travel.

Question 15Air Law and Regulations

Under the CARs, what is the required action when a pilot receives a TCAS resolution advisory?

  1. Disable the TCAS and advise ATC
  2. Request a new clearance before manoeuvring
  3. Continue the current flight path
  4. Follow the RA immediately, even if it conflicts with ATC instructions Correct answer.

Explanation

A TCAS resolution advisory requires immediate compliance to avoid a collision, and the pilot must advise ATC as soon as practicable. ATC instructions do not override a resolution advisory.

Question 16Air Law and Regulations

What is the purpose of the Canadian Aviation Regulations' requirement for a weight and balance check before flight?

  1. To verify the aircraft's fuel grade
  2. To confirm the aircraft is within its approved centre of gravity and maximum weight limits Correct answer.
  3. To calculate the aircraft's insurance premium
  4. To determine the pilot's duty time

Explanation

A weight and balance check ensures the aircraft's weight and centre of gravity remain within the limits specified in the aircraft flight manual. Operating outside these limits can degrade performance and control.

Question 17Air Law and Regulations

A commercial pilot is logging flight time in an aircraft that requires two crew members. How is the pilot's flight time recorded?

  1. Only the time during takeoff and landing
  2. Only the time spent in the left seat
  3. Only the time the pilot is manipulating the controls
  4. The entire time the pilot acts as a required crew member Correct answer.

Explanation

A pilot may log flight time for the entire period during which they act as a required crew member of an aircraft in flight. This includes time when not physically manipulating the controls.

Question 18Air Law and Regulations

What is the minimum visibility required for a special VFR clearance in a control zone?

  1. Three statute miles
  2. Five statute miles
  3. One statute mile Correct answer.
  4. Two statute miles

Explanation

Special VFR may be authorized when flight visibility is at least one statute mile and the aircraft remains clear of cloud. ATC issues the clearance, which allows operation within the control zone despite below-VFR weather.

Question 19Air Law and Regulations

A pilot operating a glider in Canada must meet which requirement regarding the carriage of documents?

  1. The pilot must carry a glider pilot licence and medical certificate Correct answer.
  2. No licence is required for glider flight
  3. A commercial licence is required for all glider flights
  4. Only a student permit is required

Explanation

Glider pilots are required to hold the appropriate licence or permit and to carry it, along with the required medical certificate, while exercising its privileges. The specific medical standard may differ from that for aeroplanes.

Question 20Air Law and Regulations

An aircraft is being ferried for maintenance with an expired annual inspection. Which document or authorization is required?

  1. A special flight permit Correct answer.
  2. A standard certificate of airworthiness
  3. A private pilot licence only
  4. A maintenance release only

Explanation

A special flight permit may be issued to allow an aircraft that does not meet all airworthiness requirements to be flown for maintenance, modification or disposal. It specifies the conditions under which the flight may occur.

Question 21Air Law and Regulations

A pilot is operating under VFR in Class E airspace above 3,000 feet AGL. What cloud clearance is required?

  1. Clear of cloud only
  2. One mile horizontally and 500 feet vertically Correct answer.
  3. Two miles horizontally and 1,000 feet vertically
  4. Three miles horizontally and 1,000 feet vertically

Explanation

In controlled airspace above 3,000 feet AGL, VFR aircraft must maintain at least one mile horizontally and 500 feet vertically from cloud, with the required flight visibility. These minima provide separation from IFR traffic.

Question 22Air Law and Regulations

A pilot receives a routing that would require flight through restricted airspace that is active. What is the correct action?

  1. Ignore the restriction if flying VFR
  2. Enter the airspace and advise ATC after passing through
  3. Obtain permission from the controlling agency before entering Correct answer.
  4. Enter only if visibility is greater than five miles

Explanation

Active restricted airspace may not be entered without permission from the controlling agency, regardless of flight rules or weather. The pilot must obtain authorization or remain clear of the area.

Question 23Air Law and Regulations

An aircraft operating under IFR in Canada must be equipped with which of the following for flight in controlled airspace?

  1. An autopilot only
  2. A radar altimeter only
  3. A Mode C transponder and appropriate navigation equipment Correct answer.
  4. A handheld GPS only

Explanation

IFR flight in controlled airspace requires a Mode C transponder and navigation equipment appropriate to the route and airspace. These support ATC surveillance and ensure the aircraft can navigate as cleared.

Question 24Air Law and Regulations

A pilot is asked by a passenger to fly below the minimum safe altitude to view wildlife. What is the pilot's obligation under the CARs?

  1. Comply if the aircraft is under 1,000 feet AGL
  2. Comply if the passenger signs a waiver
  3. Comply only if ATC approves the manoeuvre
  4. Refuse, because flight below the minimum altitude is prohibited except for takeoff, landing or emergencies Correct answer.

Explanation

CAR 602.14 prohibits flight below the minimum safe altitude except during takeoff, landing or in an emergency, and passenger requests do not create an exception. The pilot remains responsible for compliance regardless of passenger wishes.

Question 25Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

On a light aircraft, which component of the landing gear assembly absorbs the energy of a hard landing and prevents it from being transmitted directly into the airframe structure?

  1. The wheel bearing race
  2. The steering torque link
  3. The brake caliper assembly
  4. The shock strut or spring assembly Correct answer.

Explanation

The shock absorber element, whether an oleo strut or a spring/elastic unit, compresses to dissipate landing energy so that the airframe does not carry the full impact load. Brakes, bearings and torque links perform entirely different functions and do not absorb vertical impact energy.

Question 26Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

In a typical light aircraft fuel system, what is the primary purpose of the fuel selector valve?

  1. To filter water and sediment out of the fuel before it reaches the engine
  2. To automatically maintain a constant fuel pressure at the carburettor
  3. To prime the engine cylinders during start
  4. To allow the pilot to draw fuel from a selected tank and to shut off fuel flow Correct answer.

Explanation

The selector valve routes fuel from whichever tank the pilot selects and provides a positive shut-off position. Pressure regulation, filtration and priming are handled by separate components such as the engine-driven pump, gascolator and primer.

Question 27Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

What is the function of the magneto in a reciprocating aircraft engine ignition system?

  1. It steps down bus voltage to supply the avionics
  2. It generates a high-voltage pulse that fires the spark plugs without relying on the aircraft battery Correct answer.
  3. It regulates the charging rate of the battery during flight
  4. It converts AC from the alternator into DC for the electrical bus

Explanation

A magneto is a self-contained generator driven by the engine that produces its own high voltage for the spark plugs, so ignition continues even if the electrical system fails. Rectification, voltage regulation and avionics supply are functions of the alternator and electrical system.

Question 28Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

Which statement correctly describes the purpose of the empennage on a conventional light aeroplane?

  1. It stores the main fuel supply and balances the centre of gravity
  2. It houses the engine and absorbs engine torque
  3. It provides longitudinal and directional stability and carries the pitch and yaw control surfaces Correct answer.
  4. It generates most of the lift required for level flight

Explanation

The empennage comprises the horizontal and vertical stabilisers plus the elevators and rudder, giving stability about the lateral and normal axes and the means to control pitch and yaw. Lift generation, engine mounting and fuel storage belong to the wing, fuselage and fuel system.

Question 29Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

What does the red line on an aircraft tachometer indicate?

  1. The speed at which the engine should be idled
  2. The maximum continuous or maximum permissible engine speed Correct answer.
  3. The normal cruise RPM for best economy
  4. The RPM at which the magneto check is performed

Explanation

The tachometer red line marks the maximum RPM that the engine may be operated at, and exceeding it risks overstressing the engine and propeller. Idle, cruise and magneto-check speeds are all well below this limit and are not marked by the red line.

Question 30Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

A pilot notices that the ammeter shows a discharge with the engine running above idle and all electrical equipment switched off. Which is the most likely cause?

  1. The battery is fully charged
  2. The alternator or its drive belt has failed Correct answer.
  3. The master switch is selected off
  4. The voltage regulator is reducing output correctly

Explanation

With the engine running and no loads selected, the charging system should show a small charge; a sustained discharge indicates the alternator is not producing output, often through a broken belt or internal failure. A fully charged battery, an off master switch or correct regulation would not produce this indication.

Question 31Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

What is the primary function of the exhaust gas temperature gauge on a fuel-injected light aircraft engine?

  1. To indicate cylinder head cooling efficiency
  2. To help the pilot set the mixture to the desired strength by identifying peak EGT Correct answer.
  3. To measure manifold pressure at the throttle plate
  4. To show the oil temperature at the cooler outlet

Explanation

EGT responds to mixture strength, and the pilot leans by reference to peak EGT or a specified number of degrees rich or lean of peak. Cylinder head cooling, oil temperature and manifold pressure are indicated by separate CHT, oil temperature and manifold pressure gauges.

Question 32Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

During a preflight inspection the pilot finds that the brake fluid level in the reservoir is at the minimum mark and there is fluid on the inside of a main wheel. What is the most appropriate interpretation?

  1. The reservoir is overfilled and fluid is venting normally
  2. The brakes are serviceable because some fluid on the wheel is normal after landing
  3. A leak in the brake system is likely and the aircraft should not be flown until it is investigated Correct answer.
  4. The parking brake was left on and the fluid expanded

Explanation

Fluid on the wheel combined with a low reservoir indicates a hydraulic leak, which could lead to brake failure on landing or during taxi. Fluid on the wheel is not normal, and expansion from a parking brake would not lower the reservoir level.

Question 33Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

Why is a constant-speed propeller able to maintain a selected RPM as airspeed or power changes?

  1. The propeller diameter changes with centrifugal force
  2. A slip clutch allows the propeller to slip at high power settings
  3. The blades are fixed and the engine changes RPM to match the propeller
  4. A governor varies blade angle to keep the propeller load matched to the selected RPM Correct answer.

Explanation

The propeller governor senses RPM and adjusts oil pressure to change blade angle, altering the load so that RPM stays at the selected value. Fixed blades cannot do this, and neither a slip clutch nor a changing diameter is used in constant-speed propeller operation.

Question 34Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

An aircraft has a 24-volt electrical system. What is the purpose of the voltage regulator in the charging circuit?

  1. To disconnect the battery from the bus during engine start
  2. To control alternator field current so that system voltage stays within limits Correct answer.
  3. To limit the current drawn by the starter motor
  4. To convert 24 volts DC to 110 volts AC for the avionics

Explanation

The regulator modulates field current so that alternator output voltage remains at the design value regardless of RPM or load. It does not perform DC-to-AC conversion, battery isolation during start or starter current limiting.

Question 35Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

Which material property makes aluminium alloy the predominant choice for light aircraft primary structure?

  1. Its low melting point, which simplifies riveting
  2. A higher strength than steel for the same cross-section
  3. Its ability to self-heal minor cracks in service
  4. A high strength-to-weight ratio with good resistance to corrosion when protected Correct answer.

Explanation

Aluminium alloys offer a favourable strength-to-weight ratio and, when clad or anodised, resist corrosion well, which is why they dominate light airframe construction. Steel is stronger per unit area, aluminium does not self-heal and a low melting point is not a design advantage.

Question 36Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

What is the function of the oil cooler bypass valve in a light aircraft engine lubrication system?

  1. It bypasses the oil filter if the filter becomes blocked
  2. It relieves excessive oil pressure at high RPM
  3. It allows oil to bypass the cooler when the oil is cold so that it warms up and flows properly Correct answer.
  4. It returns oil directly to the sump without passing through the engine

Explanation

When oil is cold and viscous, the bypass valve routes it around the cooler to prevent excessive pressure and to allow the oil to reach operating temperature. Filter bypass, pressure relief and return to sump are handled by separate valves.

Question 37Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

What is the purpose of the carburettor heat control in a piston engine?

  1. It increases the octane rating of the fuel
  2. It heats the engine oil during cold starts
  3. It supplies heated air to the carburettor to prevent or clear induction icing Correct answer.
  4. It warms the fuel before it enters the float chamber

Explanation

Carburettor heat directs air warmed by the exhaust or an exhaust shroud into the induction system, melting or preventing ice in the venturi and throttle area. It does not heat fuel, warm the oil or alter fuel octane.

Question 38Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

During a run-up magneto check, the engine RPM drops 175 RPM when switching from BOTH to the left magneto. What does this indicate?

  1. The left magneto is inoperative and must be replaced
  2. The right magneto is faulty because the drop occurs on the left selection
  3. The engine is running too lean and the mixture must be enriched
  4. The drop is within typical limits for many light aircraft and the ignition system is probably serviceable Correct answer.

Explanation

Many light aircraft manuals permit a drop of up to about 150 to 175 RPM on each magneto, so a 175 RPM drop is at the limit but not necessarily a fault. A dead magneto would cause a much larger drop or an engine stoppage, and the selection of the left magneto does not test the right one.

Question 39Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

An aircraft with a fixed-pitch propeller is climbing at full throttle and the pilot notices the manifold pressure gauge reading close to ambient pressure. What is the most likely explanation?

  1. The turbocharger wastegate is stuck closed
  2. The engine is normally aspirated and manifold pressure cannot exceed ambient pressure Correct answer.
  3. The throttle is only partly open
  4. The manifold pressure gauge is reading the wrong scale

Explanation

In a normally aspirated engine, manifold pressure at wide-open throttle approaches ambient pressure and cannot exceed it without forced induction. A stuck-closed wastegate would produce an overboost above ambient, and a partly open throttle would give a lower, not ambient, reading.

Question 40Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

What is the purpose of the squat switch on an aircraft with retractable landing gear?

  1. It automatically applies the parking brake after landing
  2. It locks the controls during ground handling
  3. It prevents the gear from being retracted while the aircraft is on the ground Correct answer.
  4. It disables the stall warning system during taxi

Explanation

The squat or weight-on-wheels switch senses that the aircraft is on the ground and inhibits gear retraction, protecting the airframe from a wheels-up landing on the ground. It does not control parking brakes, stall warning or control locks.

Question 41Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

How does a turbocharger increase the power output of a piston engine at altitude?

  1. It injects extra fuel directly into the exhaust stream
  2. It compresses intake air using exhaust-driven turbine energy, restoring manifold pressure as altitude increases Correct answer.
  3. It increases the engine compression ratio mechanically
  4. It cools the intake charge so that more fuel can be burned

Explanation

Exhaust gases drive a turbine coupled to a compressor that raises intake manifold pressure, offsetting the loss of ambient pressure with altitude. It does not change compression ratio, and charge cooling is done by an intercooler, not the turbo itself.

Question 42Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

What is the main advantage of a semi-monocoque fuselage over a pure truss structure?

  1. It allows the aircraft to be flown without a tail section
  2. It eliminates the need for a firewall
  3. It requires no rivets or fasteners
  4. The stressed skin carries a large share of the loads, giving a stiff structure with less internal bracing Correct answer.

Explanation

In semi-monocoque construction, formers, stringers and the stressed skin share the loads, producing a stiff, aerodynamically clean structure with little internal bracing. Fasteners are still required, firewalls are still fitted and the tail remains essential.

Question 43Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

During a flight, the pilot observes that the oil pressure gauge is reading near zero while the engine is running. What is the most appropriate immediate action?

  1. Increase power to raise oil pressure
  2. Ignore the gauge because oil pressure is not critical in flight
  3. Reduce power and land as soon as practicable, treating it as a possible loss of lubrication Correct answer.
  4. Continue the flight and monitor the gauge at intervals

Explanation

Loss of oil pressure can lead to rapid engine seizure and should be treated as an emergency, with power reduced and a landing made as soon as possible. Continuing the flight, increasing power or ignoring the indication would worsen the situation.

Question 44Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

Which of the following correctly describes the function of the master switch in a light aircraft electrical system?

  1. It connects or disconnects the battery and alternator from the main electrical bus Correct answer.
  2. It selects which magneto fires the spark plugs
  3. It sets the propeller blade angle
  4. It controls the fuel flow to the engine

Explanation

The master switch controls the contactors that tie the battery and alternator to the bus, allowing the whole electrical system to be energised or isolated. Magneto selection, fuel flow and propeller pitch are controlled by entirely separate systems.

Question 45Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

What is the purpose of the fuel strainer or gascolator in a light aircraft fuel system?

  1. To trap water and sediment before the fuel reaches the carburettor or engine-driven pump Correct answer.
  2. To measure the quantity of fuel in each tank
  3. To vent fuel vapour overboard during climb
  4. To increase fuel pressure for the injectors

Explanation

The gascolator is located at the low point of the fuel system and separates water and sediment so they can be drained during preflight and prevented from reaching the engine. It does not pressurise, measure or vent fuel.

Question 46Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

What happens to the mixture strength if the throttle is opened rapidly on a carburettor engine without an accelerator pump?

  1. The mixture becomes richer because manifold pressure rises
  2. The mixture momentarily leans because airflow increases faster than fuel flow Correct answer.
  3. The mixture remains constant because the float chamber regulates it
  4. The mixture momentarily richens because fuel is drawn in more easily

Explanation

When the throttle is snapped open, manifold pressure rises and airflow increases immediately, but fuel flow lags because of its inertia and the venturi effect, producing a temporary lean condition. An accelerator pump is fitted precisely to counter this.

Question 47Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

Why must the propeller be statically balanced before installation?

  1. To allow the propeller to turn faster at idle
  2. To reduce the noise level of the engine
  3. To increase the thrust produced at a given RPM
  4. To prevent vibration that would otherwise be transmitted to the engine and airframe Correct answer.

Explanation

An unbalanced propeller produces vibration that can damage the engine mount, bearings and airframe structure, so it is balanced to place its centre of gravity on the axis of rotation. Balancing does not increase thrust, reduce noise or raise idle RPM.

Question 48Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

A pilot is planning a flight and notes that the aircraft has a 28-volt system with a 24-volt battery. What does the higher system voltage indicate about the charging system?

  1. The battery is being overcharged by design
  2. The alternator must produce a voltage above the battery's nominal voltage to charge it Correct answer.
  3. The system is actually a 12-volt system
  4. The battery must be replaced before flight

Explanation

A battery can only be charged by a source whose voltage exceeds its nominal voltage, so a 24-volt battery requires an alternator regulated to about 28 volts. This is normal design, not overcharging, a 12-volt system or a reason to replace the battery.

Question 49Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

What is the function of the firewall in a light aircraft powerplant installation?

  1. It supports the wing spar carry-through structure
  2. It acts as the primary engine mount
  3. It houses the battery and electrical bus
  4. It provides a fire-resistant barrier between the engine compartment and the cockpit Correct answer.

Explanation

The firewall is a fire-resistant bulkhead that isolates the engine compartment from the cockpit, giving the crew time to escape in the event of an engine fire. It is not the wing spar support, the battery location or the engine mount itself.

Question 50Aircraft General Knowledge (Airframe, Systems, Powerplant, Electrics)

In a light aircraft hydraulic brake system, what is the purpose of the compensating port (return port) in the master cylinder?

  1. It limits the maximum brake pressure that can be applied by the pilot to prevent wheel lock-up
  2. It bleeds trapped air out of the brake line into the reservoir during normal braking
  3. It allows hydraulic fluid to flow between the reservoir and the cylinder bore as fluid expands or contracts with temperature, and closes as soon as brake pressure is applied Correct answer.
  4. It automatically releases brake pressure when the parking brake is set

Explanation

The compensating port is a small passage connecting the reservoir to the master cylinder bore. When the piston is at rest, fluid can move through it to absorb the volume changes caused by temperature variation, and once the piston moves the seal covers the port so pressure can build in the brake line. Without it, thermal expansion could pressurise the brakes or the reservoir could not replenish fluid.