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Mauritius DCA CPL Theory study materials
Mauritius DCA CPL Theory study resources

Mauritius DCA CPL Theory practice questions

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Question 1Air Law and Procedures

Under the Mauritius Civil Air Navigation Regulations, an aircraft registered in Mauritius may not fly unless it holds a valid Certificate of Airworthiness. Which document must the pilot-in-command ensure is carried on board for that certificate to be recognised as current?

  1. Only a photocopy of the Certificate of Airworthiness held by the operator's engineering department
  2. A manufacturer's type certificate data sheet for the aircraft
  3. A verbal confirmation from the Director of Civil Aviation that the aircraft is airworthy
  4. The Certificate of Airworthiness together with a valid Certificate of Maintenance Review or equivalent maintenance release Correct answer.

Explanation

The Certificate of Airworthiness is only valid while the aircraft is maintained in accordance with an approved maintenance programme, and the crew must be able to show the current maintenance review or release alongside it. A copy held on the ground or a type certificate data sheet does not satisfy the carriage requirement.

Question 2Air Law and Procedures

An aircraft on a private flight in Mauritius enters Class C controlled airspace without a clearance. Which statement best describes the legal position of the pilot?

  1. The pilot is permitted if the aircraft is equipped with a serviceable transponder
  2. The pilot is permitted provided the aircraft remains clear of cloud and in sight of the surface
  3. The pilot commits an offence because entry into controlled airspace requires an ATC clearance Correct answer.
  4. The pilot may enter if a listening watch is maintained on the appropriate frequency

Explanation

Controlled airspace may only be entered after a clearance has been obtained from the responsible air traffic control unit. Maintaining a listening watch or carrying a transponder does not confer authority to enter. Unauthorised penetration is a breach of the regulations and is reportable.

Question 3Air Law and Procedures

In Mauritius, which authority is responsible for licensing flight crew and for the oversight of air operator certificate holders?

  1. The National Transport Authority
  2. The Mauritius Meteorological Services
  3. The Airports of Mauritius Company Limited
  4. The Department of Civil Aviation of Mauritius Correct answer.

Explanation

The Department of Civil Aviation administers the civil aviation legislation and issues flight crew licences and operator certificates. Airport companies and meteorological services provide operational support but hold no licensing powers.

Question 4Air Law and Procedures

A pilot is operating a Mauritian-registered aircraft and wishes to know the rules governing the carriage of passengers for remuneration. Which principle applies?

  1. Any private pilot licence holder may carry passengers for reward if the aircraft has fewer than ten seats
  2. Commercial air transport requires an air operator certificate and operations conducted to the applicable operating rules Correct answer.
  3. Carriage for reward is permitted provided the pilot holds a valid Class 1 medical certificate
  4. Carriage for reward is permitted if the flight remains within Mauritian territorial airspace

Explanation

Carriage of passengers for remuneration constitutes commercial air transport and requires an air operator certificate plus compliance with the commercial operating rules. Holding a higher medical class or staying inside national territory does not remove the certification requirement.

Question 5Air Law and Procedures

What is the standard meaning of the term 'ceiling' when used in an aviation weather report for a Mauritian aerodrome?

  1. The height of the highest point of the aerodrome above mean sea level
  2. The height above ground level of the lowest layer of cloud covering more than half the sky Correct answer.
  3. The vertical distance between the lowest and highest cloud layers reported
  4. The greatest height at which cloud is observed anywhere in the vicinity

Explanation

Ceiling refers to the height above ground of the lowest broken or overcast layer, that is, the lowest layer covering more than half the sky. It is not the highest cloud, a layer thickness, or an aerodrome elevation.

Question 6Air Law and Procedures

An aircraft is taxiing at Plaisance Airport and the tower instructs 'HOLD SHORT OF RUNWAY 14'. What action is required of the pilot?

  1. Proceed across the runway and report when clear of it
  2. Stop immediately on the taxiway wherever the aircraft is positioned
  3. Stop at the designated holding position and do not cross or enter the runway until further clearance is given Correct answer.
  4. Continue taxiing onto the runway and line up awaiting take-off clearance

Explanation

A hold short instruction requires the aircraft to stop at the runway holding position marking and remain clear of the runway until an explicit clearance to enter or cross is received. It is not a line-up clearance and does not permit crossing.

Question 7Air Law and Procedures

Which of the following correctly describes the applicability of the Rules of the Air regarding right of way between two aircraft approaching head-on?

  1. The faster aircraft has right of way
  2. The lower aircraft has right of way
  3. Each aircraft shall alter course to the left
  4. Each aircraft shall alter course to the right Correct answer.

Explanation

When two aircraft are approaching head-on or approximately so and there is danger of collision, each shall alter its heading to the right. Speed and height do not resolve a head-on conflict.

Question 8Air Law and Procedures

An aircraft is on final approach and another aircraft is descending to land. Which aircraft has the right of way according to the Rules of the Air?

  1. The aircraft at the higher height has the right of way in all cases
  2. Both aircraft must break off the approach and rejoin the circuit
  3. The aircraft at the lower height has the right of way, but the lower aircraft shall not cut in front of or overtake the other Correct answer.
  4. The faster aircraft has the right of way

Explanation

An aircraft at a lower height has priority over one at a higher height, but it may not use that priority to cut in front of or overtake an aircraft on final approach. The higher aircraft must give way.

Question 9Air Law and Procedures

A pilot holds a valid Private Pilot Licence issued by the Department of Civil Aviation of Mauritius. Which of the following activities is permitted without any further authorisation?

  1. Acting as pilot-in-command of a twin-engine aircraft without a type-specific class rating
  2. Carrying passengers for hire and reward on a local sightseeing flight
  3. Flying in instrument meteorological conditions without an instrument rating
  4. Carrying passengers on a non-revenue flight, provided recent experience and ratings are valid Correct answer.

Explanation

A private pilot licence permits the carriage of passengers on flights that are not for remuneration, subject to currency and appropriate ratings. Carriage for hire and reward, flying a class of aircraft not covered by a rating, and IMC flight without an instrument rating all exceed the licence privileges.

Question 10Air Law and Procedures

What is the standard validity period of a Class 2 medical certificate issued to a private pilot below the age of 40 engaged in non-commercial operations?

  1. 60 months, but not beyond the holder's 42nd birthday Correct answer.
  2. 12 months
  3. 36 months
  4. 6 months

Explanation

Under Mauritius MCAR Part MED, Issue 3 (2025), MED.A.045(a)(3), the standard Class 2 validity below age 40 is 60 months. A certificate issued before age 40 expires no later than age 42, so that limit may shorten the period. Individual medical restrictions may also reduce validity.

Question 11Air Law and Procedures

An aircraft suffers a radio communication failure in controlled airspace in visual meteorological conditions. According to standard procedures, what should the pilot do?

  1. Descend below 500 feet and proceed visually to the destination without notifying anyone
  2. Circle the last position until radio contact is restored
  3. Climb immediately to the highest available level and maintain the last assigned heading indefinitely
  4. Continue to fly in VMC, land at the nearest suitable aerodrome and report arrival to ATC by the most expeditious means Correct answer.

Explanation

In VMC the aircraft should remain clear of controlled airspace where possible, land at the nearest suitable aerodrome and inform ATC of the arrival without delay. Climbing or orbiting indefinitely is not the prescribed action.

Question 12Air Law and Procedures

Which condition must be satisfied before an aircraft may be despatched on a flight under visual flight rules at night in a controlled zone?

  1. No special equipment is required provided the sky is clear of cloud
  2. The flight must be conducted below 1,000 feet above ground level
  3. Only a torch and a serviceable landing light are required
  4. The aircraft must be equipped and the pilot qualified for the applicable night and instrument requirements prescribed for that airspace Correct answer.

Explanation

Night flight in controlled airspace requires the aircraft equipment and pilot qualifications prescribed for the airspace, which may include instrument capability. A torch and landing light or a clear sky do not satisfy those requirements.

Question 13Air Law and Procedures

A pilot receives an ATC clearance that the pilot believes will compromise safety. What is the correct course of action?

  1. Comply immediately and raise the concern after landing
  2. Accept the clearance but deviate as required without informing ATC
  3. Request an amended clearance and, if necessary, advise ATC that the clearance cannot be accepted Correct answer.
  4. Ignore the clearance and continue on the previous routing

Explanation

A pilot may request an amended clearance and must inform ATC if a clearance cannot be accepted for safety reasons. Compliance followed by later discussion, silent deviation, or ignoring the instruction all endanger other traffic.

Question 14Air Law and Procedures

In the event that an aircraft is intercepted by a military aircraft, what action should the intercepted pilot take first?

  1. Continue on the current flight plan as if no interception had occurred
  2. Take immediate evasive action by turning away from the intercepting aircraft
  3. Follow the intercepting aircraft's instructions, attempt to establish radio contact and, if possible, notify the appropriate ATC unit Correct answer.
  4. Reduce speed and descend without reference to the intercepting aircraft

Explanation

The intercepted aircraft should follow the signals and instructions of the intercepting aircraft, attempt radio contact on the designated frequencies and inform ATC. Evasive manoeuvres or ignoring the interceptor are unsafe.

Question 15Air Law and Procedures

What is the purpose of the Mauritius Flight Information Region boundary in relation to flight planning?

  1. It indicates the maximum range of radar coverage available
  2. It defines the area within which flight information and alerting services are provided for the flight Correct answer.
  3. It defines the airspace in which only commercial operators may fly
  4. It marks the limit beyond which no aircraft may fly without military permission

Explanation

A flight information region is established to provide flight information service and alerting service within defined boundaries. It is not a prohibition boundary, does not restrict operations to commercial operators and is not defined by radar range.

Question 16Air Law and Procedures

An aircraft is involved in a serious incident in Mauritius. Within what period must the pilot-in-command submit a written report to the investigating authority, unless prevented by injury?

  1. Within 10 days of the incident Correct answer.
  2. Within 48 hours of the incident
  3. Within 3 months of the incident
  4. Within 30 days of the incident

Explanation

The operator or pilot is normally required to submit a written report within about ten days of an accident or serious incident. The initial notification must be made immediately, but the written report follows within the prescribed period.

Question 17Air Law and Procedures

What does a red and white striped marker board or a red and white striped barrier at an aerodrome indicate to a taxiing aircraft?

  1. The boundary of the apron for parking purposes
  2. The threshold of the active runway
  3. The location of the aerodrome fire station
  4. A closed or unserviceable area that must not be entered Correct answer.

Explanation

Red and white striped markings denote a closed or unserviceable area, such as a closed taxiway or runway portion, which aircraft must not enter. Parking boundaries, thresholds and fire stations use different markings and signs.

Question 18Air Law and Procedures

An aircraft is flying in Class D airspace. Which statement correctly describes the service provided and the clearance requirement?

  1. Neither IFR nor VFR flights require a clearance but both receive traffic information
  2. VFR flights are prohibited from entering Class D airspace at all times
  3. Only IFR flights require a clearance and VFR flights need only advise their presence
  4. IFR and VFR flights require a clearance, and traffic information is provided about other flights Correct answer.

Explanation

Class D airspace requires a clearance for both IFR and VFR flights, and ATC provides traffic information about other flights. VFR flights are not prohibited, and simply advising presence does not constitute a clearance.

Question 19Air Law and Procedures

A pilot operating a Mauritian-registered aircraft intends to fly to a neighbouring state. What is required regarding the aircraft's documents and the pilot's licence?

  1. No documents are required for flights of less than four hours' duration
  2. Only the Mauritian documents are required because the aircraft is Mauritian-registered
  3. The licence and certificates must be carried and recognised by the foreign state, and the flight must comply with both the domestic and the destination state's rules Correct answer.
  4. Only the destination state's documents are required once the aircraft leaves Mauritian airspace

Explanation

On an international flight the licence and aircraft certificates must be carried and be acceptable to the state being entered, and the flight must satisfy both the rules of the state of registry and those of the state flown over. The aircraft registration alone does not displace the destination state's rules.

Question 20Air Law and Procedures

What is the significance of the 'A' in the aircraft nationality mark '3B' assigned to Mauritius?

  1. The prefix indicates the aircraft is approved for commercial operations only
  2. The letter identifies the aircraft category as aeroplane
  3. The prefix identifies the aircraft as belonging to the national carrier
  4. The prefix 3B identifies the state of registry as Mauritius and must be displayed with the registration mark Correct answer.

Explanation

The nationality mark 3B identifies Mauritius as the state of registry and is displayed together with the registration mark on the aircraft. It does not denote category, commercial approval or ownership.

Question 21Air Law and Procedures

An aircraft on approach experiences a windshear warning from the onboard system and encounters a sudden loss of airspeed. Which action is most consistent with established windshear recovery technique?

  1. Continue the approach unchanged because the warning is advisory only
  2. Apply maximum available power, minimise pitch change and maintain the aircraft in a safe flight path, avoiding abrupt configuration changes Correct answer.
  3. Reduce power to prevent an overspeed and lower the nose rapidly
  4. Retract flaps immediately to reduce drag and descend to regain speed

Explanation

The standard recovery from a windshear encounter is to apply maximum available thrust, avoid abrupt pitch changes and configuration changes, and fly the aircraft out of the shear. Reducing power, retracting flaps or ignoring the warning would worsen the situation.

Question 22Air Law and Procedures

An aircraft is cleared to descend to 4,000 feet with a restriction to cross a waypoint at or above 6,000 feet. The pilot's descent profile would cross the waypoint at 5,500 feet. What is the correct interpretation?

  1. The cleared level of 4,000 feet takes precedence and the restriction may be ignored
  2. The altitude restriction takes precedence and the aircraft must cross the waypoint at or above 6,000 feet Correct answer.
  3. The aircraft may cross at 5,500 feet because it is between the two values
  4. The pilot should request a new clearance before beginning the descent in all cases

Explanation

A published or issued altitude restriction at a waypoint must be met even when a lower cleared level has been given; the restriction governs the crossing altitude. The aircraft must adjust its profile to cross at or above 6,000 feet.

Question 23Air Law and Procedures

During a flight in the Mauritius FIR, a pilot becomes aware that the aircraft's altimeter subscale has been set incorrectly, causing a 300-foot error in the cleared level. What is the most appropriate immediate action?

  1. Descend 300 feet to compensate without notifying anyone
  2. Notify ATC of the altitude deviation, correct the subscale setting and adjust the aircraft to the cleared level Correct answer.
  3. Adjust the subscale without informing ATC and continue
  4. Maintain the present level and say nothing to avoid distracting ATC

Explanation

An altitude deviation must be reported to ATC promptly so that separation can be assured, and the subscale must then be corrected and the aircraft returned to the cleared level. Silent correction or concealment leaves other traffic exposed to a conflict.

Question 24Air Law and Procedures

An operator wishes to conduct a flight under instrument flight rules in airspace where the prescribed navigation performance specification applies. Which statement best reflects the operator's obligation?

  1. The specification applies only to aircraft above 5,700 kg maximum take-off mass
  2. Compliance is required only when flying in the vicinity of the aerodrome
  3. The aircraft and crew must hold the required performance-based navigation approval and the equipment must be serviceable for the route Correct answer.
  4. Any aircraft with a serviceable VOR receiver automatically satisfies the specification

Explanation

Performance-based navigation airspace requires a specific approval for the aircraft and crew and serviceable equipment capable of meeting the specification for the route. A basic VOR receiver, aircraft mass or proximity to the aerodrome does not determine compliance.

Question 25Aircraft General Knowledge - Airframe, Systems and Powerplant

On a light aircraft with a fixed-pitch propeller, what happens to the angle of attack of the propeller blades as true airspeed increases in level flight at constant rpm?

  1. It increases because centrifugal twisting moment increases
  2. It increases because the helix angle increases
  3. It remains constant regardless of airspeed
  4. It decreases because the helix angle increases Correct answer.

Explanation

The blade angle of attack is the blade pitch angle minus the helix (advance) angle. As TAS rises, the helix angle rises, so with a fixed blade pitch angle the angle of attack falls, which is why a fixed-pitch propeller cannot hold optimum efficiency across the speed range.

Question 26Aircraft General Knowledge - Airframe, Systems and Powerplant

In a piston engine, what is the primary purpose of the magneto in the ignition system?

  1. To regulate the alternator output voltage
  2. To generate its own high-tension current for the spark plugs without an external power source Correct answer.
  3. To advance the fuel injection timing
  4. To step up battery voltage for the starter motor

Explanation

A magneto is a self-contained generator in which a rotating magnet induces current in the primary winding, which is then interrupted to produce a high-voltage spark. Because it is independent of the aircraft battery, the engine can continue to run even with a total electrical failure.

Question 27Aircraft General Knowledge - Airframe, Systems and Powerplant

Which structural member of a semi-monocoque fuselage carries the primary bending loads along the length of the fuselage?

  1. The skin alone
  2. The stringers acting with the skin Correct answer.
  3. The bulkheads
  4. The floor beams

Explanation

In semi-monocoque construction the skin carries shear and pressurisation loads while the stringers stiffen it and, together with the skin, carry longitudinal bending loads. Bulkheads and frames maintain shape and distribute concentrated loads rather than providing the main bending strength.

Question 28Aircraft General Knowledge - Airframe, Systems and Powerplant

What is the function of a fuel selector valve in a light twin-engine aircraft fuel system?

  1. To allow the pilot to select which tank feeds which engine and to shut off fuel Correct answer.
  2. To automatically balance fuel between tanks
  3. To drain water from the lowest point of the system
  4. To regulate fuel pressure to the injectors

Explanation

The selector valve gives the pilot manual control over the source of fuel for each engine and provides a positive shut-off position. Automatic crossfeed balancing and water drainage are performed by separate components.

Question 29Aircraft General Knowledge - Airframe, Systems and Powerplant

During a walk-around inspection, a tyre on the main landing gear shows a deep circumferential groove worn through the tread pattern. What is the correct interpretation?

  1. Wear exposing the fabric or cords, making the tyre unserviceable Correct answer.
  2. A cosmetic mark with no airworthiness significance
  3. Evidence of correct inflation pressure
  4. Normal wear indicating the tyre should be rotated

Explanation

Tread wear that exposes the carcass cords or fabric means the protective layers are gone and the tyre no longer meets airworthiness requirements. Such a tyre must be replaced before flight; grooving to the cord is not a cosmetic or routine condition.

Question 30Aircraft General Knowledge - Airframe, Systems and Powerplant

What is the purpose of the bypass ratio in a turbofan engine?

  1. It measures the pressure ratio across the fan
  2. It measures fuel flow relative to airflow
  3. It describes the ratio of bypass air mass flow to core engine mass flow Correct answer.
  4. It describes the ratio of air passing through the core to air bypassing it

Explanation

Bypass ratio is defined as the mass flow of air passing through the bypass duct divided by the mass flow through the core. A high bypass ratio improves propulsive efficiency and reduces noise, which is why modern transport engines use large fans.

Question 31Aircraft General Knowledge - Airframe, Systems and Powerplant

In an aircraft hydraulic system, what is the function of an accumulator?

  1. To filter contaminants from the fluid
  2. To cool the hydraulic fluid
  3. To reduce system pressure permanently
  4. To store pressurised fluid to damp pressure surges and supply temporary flow Correct answer.

Explanation

A hydraulic accumulator contains a gas charge separated from the fluid and stores energy. It smooths pressure pulsations from the pump, absorbs thermal expansion, and can provide a limited supply of pressure for emergency operation.

Question 32Aircraft General Knowledge - Airframe, Systems and Powerplant

An aircraft is fitted with a constant-speed propeller controlled by a governor. If the pilot selects a higher rpm setting in level flight, what does the governor do?

  1. Reduce manifold pressure automatically
  2. Decrease blade pitch so the blades take a smaller bite and rpm rises Correct answer.
  3. Feather the propeller
  4. Increase blade pitch to reduce rpm

Explanation

The governor compares actual rpm with the selected value and adjusts oil pressure to the propeller hub to change blade angle. To increase rpm it reduces blade pitch, decreasing the load on the engine so it accelerates to the new setting.

Question 33Aircraft General Knowledge - Airframe, Systems and Powerplant

In a four-stroke piston engine, which stroke produces the greatest torque on the crankshaft?

  1. Exhaust stroke
  2. Compression stroke
  3. Induction stroke
  4. Power stroke Correct answer.

Explanation

The power stroke follows ignition, when rapidly expanding combustion gases push the piston down and deliver work to the crankshaft. The other three strokes absorb energy from the crankshaft rather than producing useful torque.

Question 34Aircraft General Knowledge - Airframe, Systems and Powerplant

A pilot notices that during climb with a fixed-pitch propeller the engine rpm slowly decreases as altitude increases. What is the most likely explanation?

  1. The propeller governor is over-speeding
  2. The magnetos are failing at altitude
  3. Decreasing air density reduces the mass flow and power output, so rpm falls Correct answer.
  4. Fuel octane rating increases with altitude

Explanation

With a fixed-pitch propeller, rpm is determined by the balance between engine power and propeller load. As altitude increases, air density and therefore engine power fall, so the propeller absorbs less power and rpm decreases unless the throttle is adjusted.

Question 35Aircraft General Knowledge - Airframe, Systems and Powerplant

What is the primary function of the compressor in a gas turbine engine?

  1. To ignite the fuel-air mixture
  2. To drive the propeller through a reduction gear
  3. To convert kinetic energy into thrust
  4. To raise the pressure of the air before it enters the combustion chamber Correct answer.

Explanation

The compressor takes in air and raises its pressure, delivering high-pressure air to the combustion chamber where fuel is added and burned. The turbine then extracts energy to drive the compressor and any accessories.

Question 36Aircraft General Knowledge - Airframe, Systems and Powerplant

In a pressurised aircraft, what is the function of the outflow valve in the cabin pressurisation system?

  1. To control the rate at which cabin air escapes, thereby regulating cabin pressure Correct answer.
  2. To admit fresh air into the cabin
  3. To supply conditioned air to the flight deck only
  4. To seal the cabin completely during flight

Explanation

The outflow valve modulates the escape of air from the cabin and is the primary control of cabin pressure and rate of change. Inflow is supplied by the air conditioning packs or engine bleed, while the outflow valve determines the resulting cabin altitude.

Question 37Aircraft General Knowledge - Airframe, Systems and Powerplant

An aircraft's electrical system shows a discharging ammeter with the engine running above idle. Which condition is most consistent with this indication?

  1. The starter motor is engaged
  2. The alternator is not producing sufficient output to carry the load Correct answer.
  3. The battery is being charged normally
  4. The voltage regulator is set too high

Explanation

A discharge indication with the engine running means the electrical load exceeds the generator or alternator output, so the battery is supplying the deficit. This points to a failed or underperforming alternator, a broken drive belt, or an excessive load.

Question 38Aircraft General Knowledge - Airframe, Systems and Powerplant

What is the purpose of the constant-speed drive (CSD) or integrated drive generator (IDG) on a transport aircraft engine?

  1. To reduce engine noise
  2. To take variable engine speed and deliver constant-frequency AC power Correct answer.
  3. To convert DC to AC for the aircraft bus
  4. To drive the hydraulic pump

Explanation

A CSD or IDG uses a hydraulic or mechanical constant-speed unit so that the generator turns at constant speed regardless of engine rpm, producing constant-frequency AC. This allows the generator to supply a stable electrical frequency to the aircraft bus.

Question 39Aircraft General Knowledge - Airframe, Systems and Powerplant

An aircraft's landing gear is held down by over-centre locks and the retraction is powered by hydraulic pressure. What is the purpose of the squat switch in this system?

  1. To apply the parking brake automatically
  2. To supply hydraulic pressure to the gear during extension
  3. To prevent gear retraction while the aircraft is on the ground Correct answer.
  4. To indicate gear position on the annunciator panel

Explanation

A squat or weight-on-wheels switch senses that the aircraft is on the ground and inhibits hydraulic selection of gear retraction, preventing an accidental wheels-up landing. Position indication and braking are separate functions.

Question 40Aircraft General Knowledge - Airframe, Systems and Powerplant

During flight, ice accumulates on the leading edge of the horizontal stabiliser. Which consequence is most significant for controllability?

  1. Reduced fuel consumption
  2. Loss of elevator effectiveness and possible tail-plane stall Correct answer.
  3. Increased elevator effectiveness
  4. Improved longitudinal stability

Explanation

Ice on the tailplane alters its aerofoil shape, reduces lift and increases the stall speed of that surface, and can also disturb the airflow over the elevator. The result can be loss of elevator authority or a tail-plane stall, which is especially dangerous because the tailplane is out of the pilot's view.

Question 41Aircraft General Knowledge - Airframe, Systems and Powerplant

What is the function of a fire detection loop in an engine fire protection system?

  1. To sense a temperature rise or flame and trigger a warning in the cockpit Correct answer.
  2. To extinguish the fire automatically
  3. To shut down the engine automatically
  4. To isolate the fuel supply to the engine

Explanation

A fire detection loop contains sensing elements that respond to overheating or flame and complete a circuit to trigger the cockpit warning. Extinguishing, shutdown, and fuel isolation are separate actions taken by the crew or by dedicated systems.

Question 42Aircraft General Knowledge - Airframe, Systems and Powerplant

In a piston engine, what is detonation and why is it harmful?

  1. The exhaust valve opens too late
  2. The spark plug fires too early, causing roughness
  3. The mixture ignites spontaneously ahead of the flame front, producing high pressures and temperatures that can damage the engine Correct answer.
  4. The fuel-air mixture burns smoothly after the spark

Explanation

Detonation occurs when the unburned charge auto-ignites ahead of the normal flame front, creating shock waves and very high local pressures and temperatures. Sustained detonation can cause piston, valve, and cylinder damage and is controlled by mixture, power, and fuel grade.

Question 43Aircraft General Knowledge - Airframe, Systems and Powerplant

A turbocharger is fitted to a piston engine. What limits the maximum manifold pressure that can be developed?

  1. The propeller pitch setting
  2. The size of the exhaust pipe
  3. The wastegate setting, which controls exhaust gas flow to the turbine Correct answer.
  4. The oil pressure in the engine

Explanation

The wastegate regulates how much exhaust gas bypasses or passes through the turbine, thereby controlling turbine and compressor speed and the resulting manifold pressure. The pilot's throttle schedules the wastegate to achieve the desired boost, and an overboost protection system may limit it further.

Question 44Aircraft General Knowledge - Airframe, Systems and Powerplant

In a gas turbine engine, what is the effect of a compressor stall or surge on engine operation?

  1. A disruption of airflow through the compressor causing loud bangs, vibration, and loss of power Correct answer.
  2. An automatic increase in fuel flow
  3. A reduction in exhaust gas temperature only
  4. A smooth increase in thrust

Explanation

Compressor surge is a breakdown of the normal airflow through the compressor, with the flow reversing momentarily and pressure pulsations occurring. It produces loud bangs, heavy vibration, and a loss of thrust, and requires prompt corrective action by the crew.

Question 45Aircraft General Knowledge - Airframe, Systems and Powerplant

Aircraft hydraulic fluid is found to be contaminated with water. What is the most likely consequence if the system is operated in this condition?

  1. Improved lubrication of the seals
  2. Reduced fluid viscosity only
  3. Higher system pressure
  4. Corrosion and possible freezing of water in the system at low temperatures Correct answer.

Explanation

Water in hydraulic fluid promotes corrosion of metal components and can freeze at low temperatures, blocking lines and restricting flow. It also degrades the fluid's lubricating properties, so contaminated fluid must be removed and the system purged.

Question 46Aircraft General Knowledge - Airframe, Systems and Powerplant

On a transport aircraft, what is the purpose of a fuel crossfeed system?

  1. To transfer fuel from one tank to another to correct lateral imbalance or feed both engines from one tank Correct answer.
  2. To transfer fuel to the APU only
  3. To increase the total fuel capacity
  4. To vent fuel overboard during refuelling

Explanation

Crossfeed allows fuel to be drawn from any tank to either engine, so the crew can correct a lateral imbalance or continue feeding both engines from a tank with a failed pump. It does not increase capacity and is not a venting or refuelling function.

Question 47Aircraft General Knowledge - Airframe, Systems and Powerplant

An aircraft with a semi-monocoque wing experiences a lightning strike on the wing tip. Which design feature most directly protects the structure?

  1. The fuel tank vents
  2. Bonding and static dischargers that provide a conductive path to dissipate the current Correct answer.
  3. The wing spar carry-through bolts
  4. The use of composite materials only

Explanation

Bonding straps and static dischargers provide a low-resistance path so lightning current flows over the aircraft surface and dissipates, rather than arcing through structure or fuel systems. The aim is to protect the airframe and prevent ignition of fuel vapour.

Question 48Aircraft General Knowledge - Airframe, Systems and Powerplant

What is the function of a propeller's feathering system on a multi-engine aircraft?

  1. To increase thrust at low airspeed
  2. To increase engine cooling on the ground
  3. To reverse thrust after landing
  4. To rotate the blades to a high-pitch, low-drag position to reduce drag after engine failure Correct answer.

Explanation

Feathering turns the blades to an edge-on, high-pitch position that minimises drag and prevents windmilling of a failed engine. This reduces asymmetric drag and helps maintain control and performance.

Question 49Flight Performance and Planning

In Mauritius DCA CPL performance planning, which speed is defined as the speed at which the aeroplane can be brought to a full stop on a dry runway within the available accelerate-stop distance?

  1. VREF
  2. V1 Correct answer.
  3. VR
  4. V2

Explanation

V1 is the decision speed: the maximum speed by which the take-off must be rejected and still allow a stop within the accelerate-stop distance available. Above V1 the take-off must be continued. VR is rotation speed and V2 is the take-off safety speed, so neither defines the reject decision.

Question 50Flight Performance and Planning

An aeroplane has a take-off mass of 2,400 kg and the AFM gives a take-off ground roll of 520 m at 2,300 kg and 610 m at 2,500 kg. Using linear interpolation, what ground roll applies at 2,400 kg (assume no other corrections)?

  1. 520 m
  2. 565 m Correct answer.
  3. 545 m
  4. 610 m

Explanation

The mass is exactly halfway between 2,300 kg and 2,500 kg, so the ground roll is halfway between 520 m and 610 m. Half of the 90 m difference is 45 m, giving 520 + 45 = 565 m. Interpolation is valid because the chart varies smoothly over this small mass range.