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CAAB CPL Theory Exam study materials
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CAAB CPL Theory Exam practice questions

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Question 1Air Law

Under the Convention on International Civil Aviation (Chicago Convention), complete and exclusive sovereignty over the airspace above a State's territory is vested in:

  1. The State concerned Correct answer.
  2. The State of registry of the aircraft in flight
  3. The United Nations
  4. ICAO

Explanation

Article 1 of the Chicago Convention recognises that every State has complete and exclusive sovereignty over the airspace above its territory. This principle is the foundation on which all subsequent rights of transit, landing and overflight are granted by agreement.

Question 2Air Law

ICAO Annex 1 to the Chicago Convention contains the Standards and Recommended Practices relating to:

  1. Aeronautical Charts
  2. Aircraft Operations
  3. Rules of the Air
  4. Personnel Licensing Correct answer.

Explanation

Annex 1 sets out the Standards and Recommended Practices for the licensing of flight crew, air traffic controllers and other aviation personnel. The other Annexes referenced cover different subject areas.

Question 3Air Law

An aircraft entered on the register of Bangladesh carries the ICAO nationality mark:

  1. 8Q
  2. BD
  3. BAN
  4. S2 Correct answer.

Explanation

ICAO allocates nationality marks that are placed before the registration mark of each aircraft. Bangladesh has been allocated the mark S2 (with S3 also assigned to it), so its aircraft are marked in the form S2-XXX.

Question 4Air Law

Under ICAO Annex 1, the minimum age for the issue of a Commercial Pilot Licence is:

  1. 17 years
  2. 21 years
  3. 16 years
  4. 18 years Correct answer.

Explanation

Annex 1 sets the minimum age for a Commercial Pilot Licence at 18 years. Higher ages apply to the Airline Transport Pilot Licence, and a lower minimum applies to the Private Pilot Licence.

Question 5Air Law

Two aircraft flying at approximately the same level on converging headings are approaching head-on. Each pilot shall:

  1. Alter heading to the right Correct answer.
  2. Maintain heading and reduce speed
  3. Climb to a higher level
  4. Alter heading to the left

Explanation

The Rules of the Air require that when two aircraft are approaching head-on or approximately so and there is danger of collision, each shall alter its heading to the right. Both aircraft therefore pass left side to left side.

Question 6Air Law

Two aircraft are approaching an aerodrome for landing at the same time. Which aircraft has the right of way?

  1. The aircraft at the higher altitude
  2. The aircraft at the lower altitude Correct answer.
  3. The faster aircraft
  4. The aircraft approaching from the right

Explanation

The aircraft at the lower altitude has the right of way, but it may not use this to cut in front of, or overtake, another aircraft on final approach. The right-of-way rule does not remove the obligation to avoid collision.

Question 7Air Law

When flying above the transition altitude, the pilot shall set the altimeter subscale to:

  1. The aerodrome QNH of departure
  2. The QFE of the nearest aerodrome
  3. Standard pressure 1013.2 hPa Correct answer.
  4. The regional QNH of the area

Explanation

Above the transition altitude all aircraft set the subscale to the standard pressure of 1013.2 hPa and fly at flight levels, which provides a common datum for all aircraft. QNH and QFE settings are used at or below the transition altitude.

Question 8Air Law

Under Article 6 of the Chicago Convention, scheduled international air services over the territory of another State may be operated only:

  1. If the aircraft is registered in that State
  2. With the special permission of that State Correct answer.
  3. When the flight is conducted under VFR
  4. If no fare-paying passengers are carried

Explanation

Article 6 provides that no scheduled international air service may be operated over or into the territory of a contracting State except with the special permission or other authorisation of that State. Such permission is normally granted through bilateral air services agreements.

Question 9Air Law

The third freedom of the air gives an airline of one State the right to:

  1. Carry traffic between two points in another State
  2. Set down traffic picked up in another State
  3. Set down in another State traffic from its own State Correct answer.
  4. Pick up traffic in another State for its own State

Explanation

The third freedom is the right to put down, in another State, traffic taken on in the State in which the aircraft is registered. The fourth freedom is the reciprocal right to take on traffic in another State destined for the aircraft's own State.

Question 10Air Law

An aircraft registered in State B has an accident in State A. The investigation of the accident is normally conducted by:

  1. The State of Occurrence Correct answer.
  2. The State of the Operator
  3. The State of Registry
  4. The State of Manufacture

Explanation

Under Annex 13 the State in which the accident occurs is responsible for instituting the investigation. Other States with a special interest, such as the State of Registry, Operator, Design and Manufacture, may appoint accredited representatives.

Question 11Air Law

An aircraft that is intercepted by another aircraft should first attempt to establish radio communication on:

  1. 121.5 MHz Correct answer.
  2. 243.0 MHz in all cases
  3. The destination aerodrome frequency
  4. 118.1 MHz

Explanation

The intercepted aircraft should immediately attempt to establish radio communication with the intercepting aircraft, or with the appropriate intercept control unit, on the emergency frequency 121.5 MHz. It should also select SSR code 7700 unless instructed otherwise.

Question 12Air Law

The SSR transponder code to be selected when the aircraft has suffered a complete radio communication failure is:

  1. 7500
  2. 7700
  3. 2000
  4. 7600 Correct answer.

Explanation

The special SSR codes are 7500 for unlawful interference, 7600 for radio communication failure and 7700 for a general emergency. A pilot who loses radio communication selects 7600 to alert ATC to the nature of the problem.

Question 13Air Law

Which statement correctly describes Class A controlled airspace?

  1. Only VFR flights are permitted
  2. IFR flights only, all flights separated from each other Correct answer.
  3. Both IFR and VFR flights are permitted when cleared
  4. IFR and VFR flights are permitted but VFR are not separated

Explanation

In Class A airspace only IFR flights are permitted and all flights are provided with air traffic control service and separated from each other. VFR flights are not admitted to Class A airspace at all.

Question 14Air Law

Under the Rules of the Air, the pilot-in-command of an aircraft:

  1. Has final authority for the operation of the aircraft Correct answer.
  2. Is responsible only for navigation of the aircraft
  3. May delegate final authority to the operator's duty officer
  4. Must follow ATC instructions in every circumstance

Explanation

The pilot-in-command has final authority as to the disposition of the aircraft while in command, and this authority cannot be transferred to a ground-based official. ATC instructions create obligations, but they do not remove that final authority.

Question 15Air Law

A pilot who is unable to comply with an ATC clearance because of an in-flight emergency shall:

  1. Advise ATC and deviate as necessary Correct answer.
  2. Squawk 7600 and leave controlled airspace
  3. Continue to comply with the clearance until landing
  4. Land at the nearest aerodrome before contacting ATC

Explanation

An emergency gives the pilot-in-command authority to deviate from the clearance to the extent required by the situation. The pilot must, as soon as practicable, inform ATC of the deviation and obtain a revised clearance.

Question 16Air Law

Which of the following must be carried on board an aircraft engaged in international navigation?

  1. Load and trim sheet
  2. Maintenance schedule
  3. Certificate of Airworthiness Correct answer.
  4. Operations manual

Explanation

Article 29 of the Chicago Convention lists the documents that must be carried on board, and these include the certificate of registration, the certificate of airworthiness, the crew licences and the journey logbook. The operations manual, maintenance schedule and load sheet are operator records not included in that list.

Question 17Air Law

The carriage of dangerous goods by air is governed by ICAO Annex:

  1. Annex 16
  2. Annex 18 Correct answer.
  3. Annex 19
  4. Annex 17

Explanation

Annex 18 contains the Standards and Recommended Practices for the safe transport of dangerous goods by air, supported by the associated Technical Instructions. It sets out how goods are classified, packed, marked and documented.

Question 18Air Law

The Tokyo Convention of 1963 deals primarily with:

  1. Suppression of unlawful seizure of aircraft
  2. Liability for damage caused by aircraft to third parties on the surface
  3. Offences committed on board aircraft Correct answer.
  4. Unification of rules on international carriage by air

Explanation

The Tokyo Convention establishes the competence of the State of registry over offences committed on board an aircraft and grants the aircraft commander certain powers. It also provides for the restoration of control of an aircraft to its commander.

Question 19Air Law

A Certificate of Airworthiness for an aircraft engaged in international navigation is issued by:

  1. The State of the Operator
  2. The State of Manufacture
  3. ICAO
  4. The State of Registry Correct answer.

Explanation

The State of registry is responsible for issuing or validating the certificate of airworthiness, and other contracting States must recognise it provided it was issued under requirements equal to or above the ICAO minimum Standards. ICAO itself issues no certificates.

Question 20Air Law

Article 7 of the Chicago Convention permits each State to:

  1. Reserve cabotage traffic to its own aircraft Correct answer.
  2. Charge landing fees to aircraft of other States
  3. Prohibit all non-scheduled flights over its territory
  4. Deny entry to aircraft without a certificate of airworthiness

Explanation

Article 7 allows each State to reserve cabotage, that is the carriage of traffic between two points within its own territory, to its own national aircraft. Foreign operators may not be granted the privilege of picking up or setting down such traffic on an exclusive basis.

Question 21Air Law

An aircraft has the nationality:

  1. Of the State in which it is operated
  2. Of both States if registered in two
  3. Of the State of the operator
  4. Of the State in which it is registered Correct answer.

Explanation

Under Article 17 an aircraft has the nationality of the State in which it is entered on the register. Article 18 further provides that an aircraft cannot be validly registered in more than one State, although transfer of registration is permitted.

Question 22Air Law

Except when taking off or landing, an aircraft shall not be flown over a congested area of a city at a height less than:

  1. 600 ft above ground level
  2. 1000 ft above the highest obstacle within 600 m Correct answer.
  3. 500 ft above the highest obstacle within 600 m
  4. 1500 ft above ground level

Explanation

Over congested areas of cities, towns or settlements, or over an open-air assembly of persons, the minimum is 1000 ft above the highest obstacle located within a horizontal radius of 600 m of the aircraft. Elsewhere the minimum is 500 ft above ground or water.

Question 23Air Law

An airship and a glider are converging at approximately the same level. Which aircraft has the right of way?

  1. The aircraft that is being overtaken
  2. The glider Correct answer.
  3. The airship
  4. The aircraft with the higher speed

Explanation

The Rules of the Air order the right of way by category: balloons have priority over gliders, gliders over airships, airships over powered heavier-than-air aircraft, and powered aircraft over all tethered craft. A glider therefore has the right of way over an airship.

Question 24Air Law

In the context of the Chicago Convention, a Standard is:

  1. A specification that is binding unless a difference is notified Correct answer.
  2. A specification that becomes binding only after ratification by each State individually
  3. A rule applicable only to aircraft engaged in commercial air transport
  4. A recommendation that States may apply at their discretion within their own territory

Explanation

A Standard is any specification whose uniform application is recognised as necessary for the safety or regularity of international air navigation. Contracting States must comply with it, but must notify ICAO if they are unable to comply, and the difference is then published.

Question 25Aircraft General Knowledge

The primary structural member of an aircraft wing that carries the main bending loads is the:

  1. Rib
  2. Skin panel
  3. Spar Correct answer.
  4. Stringer

Explanation

The spar runs spanwise and is the main beam of the wing, so it takes the bending loads generated by lift. Ribs give the wing its aerofoil shape and transfer loads to the spars, while stringers stiffen the skin.

Question 26Aircraft General Knowledge

The shimmy damper fitted to a nose landing gear is designed to:

  1. prevent the gear retracting with the wheel misaligned
  2. absorb the vertical shock loads of landing
  3. damp out rapid oscillations of the nose wheel assembly Correct answer.
  4. centre the nose wheel after take-off

Explanation

Shimmy is a rapid self-excited oscillation of the wheel about its vertical axis, and the damper provides hydraulic resistance to suppress it. Centring after take-off is done by centring cams or springs, and vertical shock is absorbed by the oleo strut.

Question 27Aircraft General Knowledge

Pascal's law, as applied to aircraft hydraulic systems, states that pressure applied to a confined fluid is:

  1. reduced in proportion to the area of the container
  2. transmitted undiminished in all directions Correct answer.
  3. converted into increased flow at the actuator
  4. dependent on the total volume of fluid in the system

Explanation

Pascal's law says that a pressure applied to an enclosed fluid is transmitted equally and undiminished to every part of the fluid and to the walls of the container. This is what allows a single pressure source to operate several actuators and to multiply force through a larger piston area.

Question 28Aircraft General Knowledge

The purpose of a fuse or circuit breaker in an aircraft electrical circuit is to:

  1. regulate the voltage supplied to the equipment
  2. protect the wiring from excessive current Correct answer.
  3. allow current to flow in one direction only
  4. show the current flowing in the circuit

Explanation

A fuse or circuit breaker is a protective device that opens the circuit when current exceeds its rated value, preventing the wiring from overheating and catching fire. Voltage regulation is done by the regulator, and one-way flow by a diode or reverse current relay.

Question 29Aircraft General Knowledge

In a four-stroke piston engine, the correct sequence of the strokes is:

  1. Compression, induction, power, exhaust
  2. Induction, compression, exhaust, power
  3. Induction, compression, power, exhaust Correct answer.
  4. Induction, power, compression, exhaust

Explanation

The cycle is induction of the fuel/air charge, compression of that charge, ignition and power, then exhaust of the burnt gases, after which the cycle repeats. Each stroke corresponds to half a revolution of the crankshaft.

Question 30Aircraft General Knowledge

Propeller blade angle is defined as the angle between the:

  1. blade axis and the engine crankshaft centreline
  2. plane of rotation and the aircraft longitudinal axis
  3. blade chord line and the relative airflow
  4. blade chord line and the plane of rotation Correct answer.

Explanation

Blade angle is a fixed geometric setting measured between the chord line of the blade and the plane of rotation. Angle of attack is a different quantity, measured between the chord line and the relative airflow, which depends on both rotational and forward speed.

Question 31Aircraft General Knowledge

The octane grade of an aviation gasoline indicates its:

  1. resistance to detonation Correct answer.
  2. energy content per kilogram
  3. resistance to freezing at low temperature
  4. maximum engine speed for which it is approved

Explanation

Octane rating is a measure of the fuel's ability to resist detonation under high pressure and temperature in the cylinder. A higher grade is required by engines of higher compression ratio or boost, not because it contains more energy.

Question 32Aircraft General Knowledge

In semi-monocoque aircraft construction, the stringers mainly:

  1. carry the fuselage loads into the floor beams
  2. form the aerodynamic shape of the structure
  3. stiffen the skin and carry longitudinal loads Correct answer.
  4. take the concentrated loads at the wing attachments

Explanation

Stringers are longitudinal members riveted to the skin; they stiffen the skin against buckling and share the longitudinal bending loads with it. The skin itself carries a large part of the shear and tension loads, which is the essence of semi-monocoque design.

Question 33Aircraft General Knowledge

Differential ailerons are used to:

  1. increase the rate of roll at high indicated airspeed
  2. allow the ailerons to be drooped and used as flaps
  3. prevent aileron flutter at high indicated airspeed
  4. reduce adverse yaw by giving the up-going aileron more travel than the down-going one Correct answer.

Explanation

Lowering an aileron increases both lift and drag on that wing, producing yaw away from the turn, which is adverse yaw. Rigging the up-going aileron to deflect further than the down-going one reduces the drag penalty on the descending wing and so reduces adverse yaw.

Question 34Aircraft General Knowledge

The pressure relief valve in an aircraft hydraulic system:

  1. maintains normal system pressure by unloading the pump
  2. prevents fluid flowing back through the pump when it is stopped
  3. limits the rate at which the system can be pressurised
  4. opens to return fluid to the reservoir if system pressure becomes excessive Correct answer.

Explanation

The relief valve is a safety device set above normal operating pressure that opens to dump fluid back to the reservoir, protecting components and lines from overpressure. Normal pressure control is the job of the pressure regulator or unloading valve.

Question 35Aircraft General Knowledge

A hydraulic accumulator in an aircraft system:

  1. removes solid contamination from the fluid
  2. measures the quantity of fluid in the system
  3. stores fluid under pressure to damp surges and supply peak demands Correct answer.
  4. cools the fluid returning to the reservoir

Explanation

An accumulator contains a trapped gas charge that is compressed as fluid enters, storing energy. It smooths pump pressure pulses, supplies extra flow during heavy demand and can provide a limited emergency supply if the pump fails.

Question 36Aircraft General Knowledge

The voltage regulator in a DC generating system:

  1. controls the field current so that generator voltage stays constant Correct answer.
  2. converts alternating current into direct current
  3. prevents the battery discharging through the generator
  4. limits the maximum current the generator can supply

Explanation

The regulator varies the current in the generator field winding, which controls the output voltage as load and speed change. It works together with a reverse current cut-out and a current limiter, each performing a different protective function.

Question 37Aircraft General Knowledge

A dry-sump lubrication system is preferred for aerobatic aircraft because:

  1. it eliminates the need for an oil cooler
  2. it uses a simpler pump than a wet-sump system
  3. it allows a lower oil pressure to be used
  4. oil is held in a separate tank and supplied in all attitudes Correct answer.

Explanation

In a wet-sump engine the oil collects in the crankcase sump, where the pickup can become uncovered during negative-g or inverted flight. A dry-sump system scavenges oil to a separate tank, from which it can be fed to the engine in any attitude.

Question 38Aircraft General Knowledge

Carburettor icing is most likely to occur when the outside air temperature is:

  1. below freezing with visible moisture and the engine at high power
  2. below about minus 20 degrees Celsius and the air is dry
  3. above plus 25 degrees Celsius with low humidity
  4. between about minus 5 and plus 15 degrees Celsius with high humidity Correct answer.

Explanation

Fuel vaporisation and the pressure drop in the venturi cool the mixture well below the outside air temperature, so ice can form with the outside air well above freezing. The risk is greatest with high relative humidity and at reduced throttle settings, such as in a descent.

Question 39Aircraft General Knowledge

Cylinder head temperatures that are too high in the cruise are most effectively reduced by:

  1. leaning the mixture to peak exhaust gas temperature
  2. opening the cowl flaps or reducing power Correct answer.
  3. increasing the power setting
  4. closing the cowl flaps

Explanation

Cowl flaps control the flow of cooling air through the engine compartment, so opening them increases cooling. Reducing power lowers the heat input to the cylinders; leaning to peak EGT, by contrast, raises combustion temperatures.

Question 40Aircraft General Knowledge

The bypass ratio of a turbofan engine is the ratio of:

  1. the air leaving the compressor to the air entering it
  2. the fan rotational speed to the high-pressure compressor speed
  3. the fuel flow to the airflow through the engine core
  4. the mass flow through the bypass duct to that through the core Correct answer.

Explanation

Bypass ratio compares the mass of air that passes through the fan and bypass duct with the mass that passes through the engine core. A high bypass ratio gives better propulsive efficiency and lower noise, which is why it is used on modern civil transports.

Question 41Aircraft General Knowledge

In a constant-speed propeller system, the propeller governor:

  1. holds RPM at one fixed value that the pilot cannot change
  2. varies blade angle to hold the RPM selected by the pilot Correct answer.
  3. limits maximum RPM by feathering the blades
  4. synchronises the engine RPM with the magneto timing

Explanation

The governor senses RPM with flyweights and, when RPM deviates from the selected value, ports oil to or from the propeller to change blade angle. The pilot selects the desired RPM with the propeller control, and the governor then maintains it.

Question 42Aircraft General Knowledge

In a pressurised aircraft, cabin altitude is controlled by:

  1. the negative pressure relief valve opening inwards
  2. the controller scheduling the amount of bleed air entering the cabin
  3. the outflow valve modulating the air leaving the cabin Correct answer.
  4. the position of the cabin air shut-off valve

Explanation

Bleed air inflow is essentially continuous, and the cabin pressure controller regulates cabin pressure by modulating the outflow valve to vary how much air escapes. This controls both cabin altitude and the rate at which it changes.

Question 43Aircraft General Knowledge

Pneumatic de-icing boots on a wing leading edge remove ice by:

  1. spraying freezing point depressant fluid onto the surface
  2. sweeping the ice off with a mechanical wiper
  3. heating the leading edge above freezing point
  4. inflating cyclically to crack the ice so the airflow carries it away Correct answer.

Explanation

The boots consist of inflatable tubes that are alternately inflated and deflated, which flexes the surface and breaks the bond between ice and skin. The airflow then removes the broken ice before it can build up again.

Question 44Aircraft General Knowledge

In a hydraulic system, the speed at which an actuating cylinder extends is determined by:

  1. the overall length of the cylinder
  2. the rate of fluid flow entering the cylinder Correct answer.
  3. the diameter of the return line to the reservoir
  4. the pressure setting of the relief valve

Explanation

Actuator speed follows from continuity of flow: the piston speed equals flow rate divided by piston area. Pressure sets the force the actuator can produce, so flow and pressure govern speed and force respectively.

Question 45Aircraft General Knowledge

The reverse current cut-out in a DC generator circuit is fitted to:

  1. limit the generator output to its rated current
  2. open the circuit when current starts to flow from the battery into the generator Correct answer.
  3. prevent the generator voltage exceeding the regulated value
  4. disconnect the generator if its field winding fails

Explanation

If generator output voltage falls below bus voltage, for example at low RPM or after engine shutdown, the battery would discharge through the generator and could damage it. The cut-out senses the reversal of current direction and opens the generator circuit.

Question 46Aircraft General Knowledge

A gas turbine compressor is most likely to surge when:

  1. the engine is at maximum RPM in very cold air
  2. the throttle is advanced too rapidly or the intake airflow is distorted Correct answer.
  3. the engine is new and the compressor blades are clean
  4. the turbine inlet temperature is held below its limit

Explanation

Surge is a breakdown of the smooth airflow through the compressor when the pressure ratio demanded exceeds what the blades can sustain. Rapid throttle changes, a dirty or damaged compressor, and distorted intake airflow are typical triggers, and the airflow may even reverse momentarily.

Question 47Aircraft General Knowledge

If the ignition timing of a piston engine is excessively advanced, the most likely result is:

  1. late combustion with a loss of power
  2. a reduction in cylinder head temperature
  3. a smoother idle with lower fuel consumption
  4. detonation with possible engine damage Correct answer.

Explanation

Advancing the spark causes the charge to burn earlier, so peak cylinder pressure and temperature rise and the end gas may ignite spontaneously, which is detonation. Sustained detonation can lead to pre-ignition and structural damage to pistons and valves.

Question 48Aircraft General Knowledge

Vapour lock in a piston engine fuel system occurs when:

  1. the mixture becomes excessively rich with altitude
  2. fuel vaporises in the lines and stops liquid fuel flow Correct answer.
  3. the fuel pump delivers more pressure than the carburettor can accept
  4. fuel freezes in the filter during a long descent

Explanation

A volatile fuel at low ambient pressure and high temperature can boil in the lines or pump, forming bubbles that the pump cannot move. The result is a reduced or interrupted supply of liquid fuel to the engine, which can cause rough running or a power loss.

Question 49Flight Performance and Planning

Density altitude is defined as the altitude at which the aircraft would perform as if it were at

  1. true altitude above mean sea level
  2. pressure altitude corrected for non-standard temperature Correct answer.
  3. height above the aerodrome reference point
  4. indicated altitude corrected for instrument and position error

Explanation

Density altitude combines pressure altitude with the effect of temperature deviation from the standard atmosphere. It is the altitude corresponding to the actual air density, and it is this density that determines engine, propeller and wing performance.

Question 50Flight Performance and Planning

During takeoff, the effect of a headwind compared with still air is that the ground roll and the total distance to 50 ft will

  1. remain unchanged
  2. decrease only after liftoff
  3. both increase
  4. both decrease Correct answer.

Explanation

A headwind reduces the ground speed needed to reach any given airspeed, so the aircraft covers less ground before reaching lift-off and before reaching 50 ft. Both the ground roll and the total takeoff distance therefore shorten.