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Norway ATPL Theory study materials
Norway ATPL Theory study resources

Norway ATPL Theory practice questions

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Question 1Air Law and ATC Procedures

Under the Norwegian Aviation Act and the standard rules of the air, which document must the pilot in command of a Norwegian-registered aircraft carry on board for every flight?

  1. The aircraft maintenance programme and the mass and balance report
  2. The type certificate and the noise certificate
  3. The insurance policy and the airworthiness review certificate
  4. The certificate of registration and the certificate of airworthiness Correct answer.

Explanation

The Chicago Convention Annex 8 framework, implemented through the Norwegian Aviation Act, requires the certificate of registration and the valid certificate of airworthiness to be carried on board. These documents establish nationality and continuing airworthiness status at any inspection. Other documents are normally kept by the operator on the ground.

Question 2Air Law and ATC Procedures

A flight is conducted under instrument flight rules in controlled airspace. Which minimum horizontal distance from cloud must be maintained when the aircraft is not in airspace where a reduced separation has been specifically authorised?

  1. 6000 m
  2. 1500 m Correct answer.
  3. 8000 m
  4. 3000 m

Explanation

The standard IFR meteorological minima in controlled airspace require a horizontal distance from cloud of at least 1500 m, together with a vertical distance of 300 m and a flight visibility of 8 km. These minima derive from ICAO Annex 2 and are reflected in the Norwegian SERA rules. Reduced separation applies only where specifically prescribed.

Question 3Air Law and ATC Procedures

An aircraft is on final approach and the tower controller clears it to land. What does this clearance authorise the pilot to do?

  1. Enter the runway immediately without further lookout
  2. Proceed to land, but remain responsible for ensuring the runway is clear before touchdown Correct answer.
  3. Disregard any subsequent instruction from the tower
  4. Descend below the decision altitude regardless of visual reference

Explanation

A landing clearance authorises the flight to continue the approach and land, but the pilot in command retains responsibility for the safety of the flight. If the runway is obstructed or unsafe, the landing must be discontinued. The clearance does not transfer responsibility for collision avoidance to the controller.

Question 4Air Law and ATC Procedures

Which transponder code is universally used to indicate unlawful interference (hijacking) and must be selected when such a situation occurs?

  1. 7600
  2. 7700
  3. 7000
  4. 7500 Correct answer.

Explanation

The special squawk codes are standardised by ICAO: 7500 for unlawful interference, 7600 for radio communication failure and 7700 for general emergency. Selecting 7500 alerts air traffic control that the aircraft is being subjected to unlawful interference. These codes must be memorised exactly.

Question 5Air Law and ATC Procedures

In Norwegian airspace, an aircraft operating under visual flight rules in class G airspace below 900 m above mean sea level must maintain a flight visibility of at least which value?

  1. 3 km
  2. 5 km Correct answer.
  3. 1.5 km
  4. 8 km

Explanation

For VFR flight in class G airspace below 900 m AMSL, the prescribed flight visibility is 5 km with cloud clearance of 1500 m horizontally and 300 m vertically. These minima come from the SERA regulation applicable in Norway. Higher minima apply at greater altitudes.

Question 6Air Law and ATC Procedures

An aircraft on a scheduled international flight suffers a radio communication failure in controlled airspace and has been cleared to follow the standard arrival route. In the absence of any specific instruction from ATC, what should the pilot normally do?

  1. Turn back to the departure aerodrome without following any published procedure
  2. Maintain the last assigned level until fuel exhaustion
  3. Descend immediately below the minimum safe altitude to obtain visual ground contact
  4. Continue on the last acknowledged clearance and route, and land at the destination aerodrome after following the prescribed arrival procedure Correct answer.

Explanation

Under the ICAO communication failure procedure, the aircraft should continue in accordance with the last acknowledged clearance, follow the prescribed route, and complete the approach and landing at the destination aerodrome. Altitude changes are made according to published procedures, not arbitrarily. This allows ATC to predict the aircraft's position and protect the airspace.

Question 7Air Law and ATC Procedures

A pilot requires a clearance to enter class C airspace in Norway. Which of the following correctly describes the requirement before entry?

  1. An explicit ATC clearance must be obtained before entering the airspace Correct answer.
  2. A radio call on the frequency is sufficient and no reply is needed
  3. No clearance is required provided the aircraft remains outside controlled airspace laterally
  4. Entry is permitted as long as the transponder is operating

Explanation

Class C airspace is controlled airspace, and an explicit clearance must be received before entering it. A transmission alone does not constitute a clearance, and the pilot must wait for the controller's response. The transponder does not authorise entry into controlled airspace.

Question 8Air Law and ATC Procedures

An aircraft is cleared to descend to flight level 70. The altimeter sub-scale is set to the standard pressure of 1013.2 hPa. What does the aircraft's altimeter indicate once established at the cleared level?

  1. True altitude above mean sea level
  2. Height above the aerodrome
  3. Pressure altitude referenced to the standard datum Correct answer.
  4. Radio altitude above the terrain

Explanation

When the altimeter is set to the standard pressure 1013.2 hPa, it indicates pressure altitude referenced to that datum, which is why flight levels are used above the transition altitude. It does not indicate true altitude or height above the aerodrome. Terrain clearance must be ensured through the flight level system and minimum flight altitudes.

Question 9Air Law and ATC Procedures

During a flight in controlled airspace, a controller issues an instruction that the pilot believes will cause the aircraft to conflict with terrain. What is the correct action?

  1. Request clarification or an amended clearance, and if necessary exercise the emergency authority of the pilot in command Correct answer.
  2. Reduce speed and wait for the controller to notice the conflict
  3. Ignore the instruction and continue on the current heading without informing ATC
  4. Comply immediately because ATC instructions always take precedence over terrain clearance

Explanation

The pilot in command has final authority over the aircraft and may deviate from an instruction when safety requires it, but must inform ATC as soon as practicable. The correct first step is to query the instruction or request an amendment. Blind compliance with a hazardous instruction is not acceptable.

Question 10Air Law and ATC Procedures

An aircraft is approaching an aerodrome with a published instrument approach procedure. The approach chart shows a decision altitude of 300 ft above the aerodrome elevation for a precision approach. What does the decision altitude represent?

  1. The altitude at which the landing gear must be extended
  2. The altitude at which a missed approach must be initiated if the required visual reference has not been established Correct answer.
  3. The minimum altitude for the initial approach segment
  4. The altitude at which the aircraft must be fully configured for landing

Explanation

The decision altitude is the altitude at which a missed approach must be initiated if the required visual reference to continue the approach has not been established. It is referenced to the aerodrome elevation for precision approaches. It is not a configuration or gear extension altitude.

Question 11Air Law and ATC Procedures

A Norwegian-registered aircraft is operated under commercial air transport. Which body is responsible for issuing the air operator certificate that authorises the operation?

  1. The aerodrome operator at the main base
  2. The manufacturer of the aircraft
  3. The international organisation issuing the aircraft type certificate
  4. The civil aviation authority of the state of the operator Correct answer.

Explanation

The air operator certificate is issued by the competent civil aviation authority of the state of the operator, in Norway the Civil Aviation Authority. It confirms that the operator has the organisation, procedures and resources required for safe commercial operation. Manufacturers and aerodrome operators have no role in issuing it.

Question 12Air Law and ATC Procedures

An aircraft is taxiing on an aerodrome and the tower instructs it to hold short of a runway. What does this instruction require the pilot to do?

  1. Stop on the runway centreline and wait for take-off clearance
  2. Enter the runway and hold at the far side
  3. Stop before the runway holding position marking and not cross it without a further clearance Correct answer.
  4. Continue taxiing but reduce speed near the runway

Explanation

A hold short instruction requires the aircraft to stop before the runway holding position marking, which protects the runway strip. The aircraft must not cross the marking until a specific clearance is received. This prevents runway incursions and protects landing and departing traffic.

Question 13Air Law and ATC Procedures

In the event of an emergency, a pilot may deviate from the rules of the air. Which condition must be satisfied for such deviation to be lawful?

  1. The deviation must be recorded in the technical log before landing
  2. The deviation must be limited to altitude changes only
  3. The deviation must be approved in advance by the operator's chief pilot
  4. The deviation must be necessary to meet the emergency and the pilot must inform ATC as soon as practicable Correct answer.

Explanation

The rules of the air permit deviation in an emergency to the extent necessary to meet the situation, and the pilot must notify ATC as soon as practicable. The authority arises from the emergency itself, not from prior approval. The pilot remains responsible for the safety of the flight throughout.

Question 14Air Law and ATC Procedures

An aircraft is flying at flight level 350 in the North Atlantic region. Which altimeter setting is used and what does the indicated level represent?

  1. QNH of the nearest station, indicating true altitude
  2. Standard pressure 1013.2 hPa, indicating a flight level referenced to that datum Correct answer.
  3. Local QNH, indicating altitude above mean sea level
  4. QFE of the destination, indicating height above the aerodrome

Explanation

Above the transition level, altimeters are set to the standard pressure 1013.2 hPa and the aircraft flies at flight levels referenced to that datum. This ensures all aircraft in the same airspace use a common reference. Local QNH and QFE are used only below the transition level.

Question 15Air Law and ATC Procedures

An aircraft on an IFR flight is cleared to descend from flight level 200 to 8000 ft. The transition level at the destination is flight level 50. At what point should the pilot change the altimeter setting from standard pressure to QNH?

  1. Only after landing
  2. Immediately upon receiving the descent clearance
  3. When passing the transition level, before reaching the cleared altitude Correct answer.
  4. When passing 10 000 ft regardless of the transition level

Explanation

The altimeter setting is changed from standard pressure to QNH when the aircraft passes the transition level. This ensures the aircraft remains on a common reference until it leaves the flight level system. Changing early or late can compromise separation with other traffic.

Question 16Air Law and ATC Procedures

An aircraft is cleared to hold at a VOR using a published holding pattern with right-hand turns. The inbound course is 090 degrees. Which outbound heading should the pilot fly during the outbound leg in a standard holding pattern with no wind?

  1. 180 degrees
  2. 090 degrees
  3. 270 degrees Correct answer.
  4. 360 degrees

Explanation

In a holding pattern the outbound leg is flown on the reciprocal of the inbound course. With a 090 degree inbound course and no wind, the outbound heading is 270 degrees. Right-hand turns determine the direction in which the aircraft turns onto the outbound leg, not the outbound heading itself.

Question 17Aircraft General Knowledge: Airframe, Systems and Powerplant

On a typical transport-category aeroplane, what is the primary structural function of the wing spar?

  1. It provides the aerodynamic shape that generates lift
  2. It supports the flap track fairings
  3. It carries the bending loads generated by lift from the wing skin to the fuselage Correct answer.
  4. It houses the fuel tank vent lines

Explanation

The spar is the main load-bearing member of the wing, taking bending moments and shear from the skin and transmitting them into the fuselage attachments. The aerodynamic contour is provided by ribs and skin, not by the spar itself.

Question 18Aircraft General Knowledge: Airframe, Systems and Powerplant

Which material property makes carbon-fibre reinforced plastic attractive for primary aeroplane structure?

  1. High thermal conductivity
  2. Low cost of raw material
  3. High specific strength and stiffness Correct answer.
  4. Isotropic behaviour in all directions

Explanation

CFRP offers high strength and stiffness per unit mass, which is why it is used in primary structure such as wing and fuselage skins. It is not isotropic; its properties depend on the direction of the fibres.

Question 19Aircraft General Knowledge: Airframe, Systems and Powerplant

In a semi-monocoque fuselage, what is the role of the frames (bulkheads)?

  1. They transmit engine thrust to the wing
  2. They form the pressure-tight outer skin
  3. They carry the primary longitudinal bending loads
  4. They maintain the cross-sectional shape and support the skin against buckling Correct answer.

Explanation

Frames and formers hold the fuselage cross-section and stabilise the skin, while longitudinal stringers carry bending loads. The skin itself is the pressure boundary in a pressurised fuselage.

Question 20Aircraft General Knowledge: Airframe, Systems and Powerplant

What is the purpose of a hydraulic accumulator in an aircraft hydraulic system?

  1. To store pressurised fluid and damp pressure fluctuations and transient demands Correct answer.
  2. To cool the hydraulic fluid after prolonged operation
  3. To isolate the system in the event of an engine fire
  4. To filter contamination from the hydraulic fluid

Explanation

The accumulator contains a gas charge separated from the fluid and smooths pressure peaks, supplies short-term flow for high-demand consumers and maintains pressure when pumps are unloaded. Filtration and cooling are performed by other components.

Question 21Aircraft General Knowledge: Airframe, Systems and Powerplant

In a gas turbine engine, what is the function of the diffuser section of the compressor outlet?

  1. It meters fuel into the airflow
  2. It increases air velocity to improve combustion mixing
  3. It drives the accessory gearbox
  4. It reduces air velocity and increases static pressure before combustion Correct answer.

Explanation

The diffuser converts kinetic energy of the high-velocity compressor discharge into static pressure, slowing the air before it enters the combustion chamber. This provides the pressure rise needed for efficient combustion.

Question 22Aircraft General Knowledge: Airframe, Systems and Powerplant

On a constant-speed propeller with a hydraulically operated pitch-change mechanism, what happens if oil pressure to the propeller is lost on a single-acting counterweight design?

  1. The propeller immediately feathers regardless of design
  2. The engine automatically shuts down
  3. The blades lock rigidly at their current pitch
  4. The blades tend to move towards fine pitch or feather depending on the design, and the propeller overspeeds Correct answer.

Explanation

In a single-acting system, oil pressure normally opposes centrifugal and counterweight forces; loss of oil pressure allows those forces to drive the blades toward low pitch, causing overspeed unless a governing feature prevents it. The exact result depends on whether the design is counterweight or spring assisted.

Question 23Aircraft General Knowledge: Airframe, Systems and Powerplant

Why is a fuel/oil heat exchanger used on many turbine engines?

  1. To increase the fuel temperature to improve combustion efficiency
  2. To separate water from the fuel before it reaches the engine
  3. To cool the engine oil using fuel while warming the fuel to prevent ice formation Correct answer.
  4. To reduce the viscosity of the oil for easier starting

Explanation

The fuel/oil heat exchanger transfers heat from the engine oil to the fuel, cooling the oil and warming the fuel so that dissolved or free water does not freeze in the fuel system. This dual function is why it is fitted on many turbofan installations.

Question 24Aircraft General Knowledge: Airframe, Systems and Powerplant

What is the purpose of a torque link (scissors) on an aircraft landing gear oleo strut?

  1. It transmits braking torque to the wheel
  2. It prevents rotation of the piston in the cylinder while allowing vertical travel Correct answer.
  3. It provides the main vertical shock absorption
  4. It locks the gear in the down position

Explanation

The torque links connect the piston to the cylinder and prevent relative rotation, so the wheel remains correctly aligned while the strut compresses and extends. Shock absorption is provided by the oleo's gas and oil.

Question 25Aircraft General Knowledge: Airframe, Systems and Powerplant

An aeroplane is in a steady climb and the pilot selects the landing gear up. Which statement about the gear retraction system is correct?

  1. The gear is held up by mechanical uplocks, and hydraulic pressure is then removed Correct answer.
  2. The gear retracts under gravity after the doors open
  3. The gear retracts only when the flaps are fully up
  4. The gear is held up solely by hydraulic pressure maintained by the pump

Explanation

On most transports the gear is retracted hydraulically and secured by mechanical uplocks so that the system can be depressurised without the gear falling. Hydraulic pressure alone is not relied upon to hold the gear up.

Question 26Aircraft General Knowledge: Airframe, Systems and Powerplant

What is the effect of a compressor surge (stall) on a gas turbine engine?

  1. A rise in exhaust gas temperature only during start
  2. A sudden reversal of airflow through the compressor with loud bangs and possible flame-out Correct answer.
  3. An increase in compressor pressure ratio and thrust
  4. A gradual loss of compressor efficiency with no audible indication

Explanation

Surge is an unstable condition in which the compressor cannot maintain its pressure ratio, causing momentary flow reversal, bangs and possible flame-out or damage. It is distinct from a rotating stall, which is a localised cell of stalled blades.

Question 27Aircraft General Knowledge: Airframe, Systems and Powerplant

In a pressurised aeroplane, what is the function of the outflow valve?

  1. It modulates the rate at which cabin air leaves the fuselage to control cabin pressure Correct answer.
  2. It controls the temperature of the cabin supply air
  3. It relieves pressure only when the cabin altitude exceeds 14,000 ft
  4. It admits fresh air into the cabin from the air-conditioning packs

Explanation

The outflow valve is the controllable exit for cabin air; its position determines cabin pressure and rate of change, working with the inflow from the air-conditioning packs. It is normally automatic but can be controlled manually.

Question 28Aircraft General Knowledge: Airframe, Systems and Powerplant

What happens to the indicated airspeed and true airspeed of an aeroplane as it climbs at constant indicated airspeed?

  1. Indicated airspeed stays constant while true airspeed increases Correct answer.
  2. Indicated airspeed increases while true airspeed stays constant
  3. Both indicated and true airspeed decrease
  4. Both indicated and true airspeed increase

Explanation

Indicated airspeed reflects dynamic pressure, which depends on density; as density falls with altitude, true airspeed must rise to maintain the same dynamic pressure. This is why TAS is higher than IAS at altitude.

Question 29Aircraft General Knowledge: Airframe, Systems and Powerplant

Which statement correctly describes the operation of a bleed-air anti-ice system on a turbojet aeroplane?

  1. The surfaces are protected by inflatable rubber boots
  2. Hot compressor bleed air is routed through the leading edges of the affected surfaces Correct answer.
  3. Electrical heating elements are embedded in the leading edges
  4. A chemical de-icing fluid is sprayed onto the surfaces

Explanation

Bleed-air anti-ice systems take hot air from the engine compressor and distribute it through the wing and tail leading edges to keep them above freezing. This prevents ice formation rather than removing it after it forms.

Question 30Aircraft General Knowledge: Airframe, Systems and Powerplant

During a rejected take-off, what is the main function of the auto-brake system in the RTO mode?

  1. To apply maximum braking as soon as the thrust levers are retarded with the spoilers deployed Correct answer.
  2. To increase reverse thrust application
  3. To prevent the nosewheel from touching down
  4. To apply braking proportional to pedal input

Explanation

In RTO mode, the auto-brake system commands full braking once the thrust levers are retarded and the spoilers deploy, so that maximum deceleration is achieved without relying on pilot reaction. It is armed before take-off and disarmed after a normal take-off.

Question 31Aircraft General Knowledge: Airframe, Systems and Powerplant

Why is the combustion chamber of a gas turbine engine provided with a primary zone and a secondary (dilution) zone?

  1. To prevent the compressor from surging
  2. To increase the fuel flow in the primary zone for thrust augmentation
  3. To provide a stable rich primary zone for combustion and add air downstream to cool the gases before the turbine Correct answer.
  4. To reduce the compressor pressure ratio

Explanation

The primary zone burns a near-stoichiometric mixture for stability, while secondary and dilution air complete combustion and lower the gas temperature to a level the turbine can tolerate. This staged air admission also helps control emissions.

Question 32Aircraft General Knowledge: Airframe, Systems and Powerplant

Which of the following is the main structural advantage of a fail-safe (damage-tolerant) design philosophy?

  1. The structure relies on a single primary load path for simplicity
  2. The structure never needs inspection because it is designed to infinite life
  3. The structure is lighter because all redundant load paths are removed
  4. The structure can sustain a defined level of damage without catastrophic failure until it is detected and repaired Correct answer.

Explanation

Fail-safe design provides redundant load paths so that a crack or failure in one element can be carried by others until inspection finds and repairs it. This is why scheduled structural inspections are an essential part of the philosophy.

Question 33Aircraft General Knowledge: Airframe, Systems and Powerplant

An aircraft is fitted with a DC generator and a battery. What is the purpose of the generator control unit (GCU)?

  1. It selects which hydraulic pump is running
  2. It converts AC to DC for the battery charger only
  3. It controls the cabin lighting circuit
  4. It regulates generator output and controls connection to the busbar and protection functions Correct answer.

Explanation

The GCU regulates the generator voltage, controls the generator contactor connecting it to the busbar, and provides over-voltage, under-voltage and over-current protection. It also manages paralleling with other generators.

Question 34Aircraft General Knowledge: Airframe, Systems and Powerplant

A turbojet engine's exhaust gas temperature (EGT) is used as an indicator of engine condition. Which statement about EGT is correct?

  1. EGT is measured at the compressor inlet to monitor inlet temperature
  2. EGT is used only to indicate the oil temperature
  3. EGT is independent of fuel flow and ambient conditions
  4. EGT is measured downstream of the combustion chamber and is a primary limit during take-off and starting Correct answer.

Explanation

EGT probes are located at the turbine inlet or exhaust, and the reading reflects combustion and turbine conditions. It is a limiting parameter during take-off and start because excessive EGT can damage the turbine.

Question 35Aircraft General Knowledge: Airframe, Systems and Powerplant

In a multi-engine aeroplane, what is the purpose of the propeller synchronisation system?

  1. To control the propeller pitch during reverse thrust
  2. To increase the pitch of the propellers during take-off
  3. To feather all propellers simultaneously in an emergency
  4. To match the rotational speeds of the propellers to reduce beat frequency noise and vibration Correct answer.

Explanation

Synchronisation adjusts the governed speed of the propellers so that they rotate at the same speed, eliminating the audible beat caused by slightly different RPM. Synchrophasing goes further by matching blade positions.

Question 36Aircraft General Knowledge: Airframe, Systems and Powerplant

A transport aeroplane's hydraulic system uses two engine-driven pumps and one electric pump. During cruise, one engine fails and its pump stops. What is the most likely consequence for the hydraulic system?

  1. All hydraulic pressure is lost immediately
  2. The electric pump automatically shuts down to save power
  3. The system pressure doubles because the load is shared between fewer pumps
  4. The remaining engine-driven pump and the electric pump maintain system pressure, possibly with reduced flow for high-demand consumers Correct answer.

Explanation

Redundant pump arrangements are designed so that loss of one pump does not cause total loss of system pressure; the remaining pumps maintain pressure, though flow capacity may be reduced for simultaneous high-demand users. This is why system design considers the failure case of any single pump.

Question 37Aircraft General Knowledge: Instruments and Electronics

In a light aircraft pitot-static system, which pressure source is connected to the airspeed indicator's capsule to produce the dynamic pressure reading?

  1. The cabin altitude pressure from the cabin altimeter
  2. Only the static pressure from the static port
  3. The difference between pitot pressure and static pressure, sensed across the capsule Correct answer.
  4. Only the pitot (total) pressure from the pitot tube

Explanation

The airspeed indicator capsule is fed with pitot (total) pressure inside the capsule and static pressure around it, so the capsule expands by the difference, which is dynamic pressure. Neither pressure alone gives airspeed; the instrument responds only to their difference. This differential is then displayed on a calibrated scale in knots.

Question 38Aircraft General Knowledge: Instruments and Electronics

An aircraft climbs at constant true airspeed while the outside air temperature falls. What happens to the indicated airspeed if the pitot-static system is unobstructed?

  1. It stays exactly the same because true airspeed is constant
  2. It increases because the capsule senses a larger pressure difference
  3. It oscillates as the static port compensates for temperature
  4. It decreases because the dynamic pressure falls with decreasing air density Correct answer.

Explanation

Indicated airspeed depends on dynamic pressure, which equals half the density times the square of true airspeed. As density decreases with altitude, dynamic pressure for a given true airspeed falls, so indicated airspeed decreases. True airspeed is therefore always higher than indicated airspeed at altitude.

Question 39Aircraft General Knowledge: Instruments and Electronics

What is the purpose of the pitot heat system on an aircraft operating in instrument meteorological conditions?

  1. To prevent ice formation in the pitot tube that would block total pressure Correct answer.
  2. To heat the airspeed indicator capsule for accurate readings at altitude
  3. To warm the static port so that the altimeter reads correctly
  4. To dry the inside of the gyro instruments during descent

Explanation

Ice can block the pitot tube opening and trap total pressure, causing airspeed indications to become erroneous or frozen. Pitot heat keeps the tube clear so total pressure continues to reach the airspeed indicator. The static port is a separate opening and is not normally protected by pitot heat.

Question 40Aircraft General Knowledge: Instruments and Electronics

An aircraft in level flight has its static port completely blocked by ice while the pitot tube remains clear. During a subsequent climb, how will the airspeed indicator behave?

  1. It will read progressively higher than actual airspeed
  2. It will read progressively lower than actual airspeed and may reach zero Correct answer.
  3. It will reverse direction and indicate a descent
  4. It will remain accurate because the pitot tube is still clear

Explanation

With the static port blocked, the static pressure trapped in the instrument stays at the value from the moment of blockage. As the aircraft climbs, actual static pressure falls, so the trapped higher static pressure makes the capsule sense a smaller difference from pitot pressure. The result is an indicated airspeed that under-reads and can fall toward zero in a climb.

Question 41Aircraft General Knowledge: Instruments and Electronics

In a conventional altimeter, what does the subscale (pressure setting) knob adjust?

  1. The maximum altitude the instrument can indicate
  2. The reference pressure against which the capsule deflection is displayed Correct answer.
  3. The internal temperature compensation of the capsule
  4. The rate at which the pointer moves during a climb

Explanation

The subscale sets the pressure datum used by the altimeter, so that the displayed altitude corresponds to a chosen reference such as QNH or standard pressure. Rotating the knob moves the scale relative to the capsule position without changing the actual pressure sensed. This is why the indicated altitude changes when the pressure setting is altered on the ground.

Question 42Aircraft General Knowledge: Instruments and Electronics

An aircraft on the ground at an aerodrome with elevation 500 ft has the altimeter set to QNH. What altitude does it indicate?

  1. The height above the aerodrome reference point
  2. The pressure altitude for the aerodrome
  3. Zero feet
  4. The aerodrome elevation, approximately 500 ft Correct answer.

Explanation

QNH is the pressure setting that makes the altimeter read aerodrome elevation when the aircraft is on the ground at that aerodrome. With the correct QNH set, the instrument therefore shows approximately 500 ft, not zero. Zero would require the QFE setting instead.

Question 43Aircraft General Knowledge: Instruments and Electronics

What is the main limitation of a simple altimeter when flying from a high-pressure area into a low-pressure area without updating the subscale?

  1. The altimeter will under-read, so the aircraft is higher than indicated
  2. The altimeter will freeze at the last set pressure
  3. The altimeter will read accurately because pressure changes are compensated
  4. The altimeter will over-read, so the aircraft is lower than indicated Correct answer.

Explanation

If the pressure setting is not updated when flying toward lower pressure, the altimeter interprets the lower ambient pressure as a higher altitude. The aircraft is therefore lower than the instrument shows, which is a terrain-clearance hazard. The rule is high to low, look out below.

Question 44Aircraft General Knowledge: Instruments and Electronics

In a turn coordinator, what does the miniature aircraft primarily indicate?

  1. The pitch attitude of the aircraft
  2. The rate of climb or descent
  3. The rate of turn about the vertical axis Correct answer.
  4. The angle of bank only

Explanation

The turn coordinator uses a canted gyro so that the miniature aircraft responds to rate of turn about the vertical axis and also shows roll. It is used with the slip-skid indicator to coordinate turns. It does not indicate pitch or vertical speed.

Question 45Aircraft General Knowledge: Instruments and Electronics

Why does a vacuum-driven attitude indicator remain erect during normal flight?

  1. Because the rotor is deliberately made unbalanced
  2. Because the instrument is rigidly mounted to the airframe
  3. Because the gyro spin axis is aligned with the aircraft's longitudinal axis
  4. Because gravity acts on the gyro's pendulous vanes to apply corrective torques Correct answer.

Explanation

The attitude indicator gyro is erected by pendulous vanes that sense gravity and bleed air asymmetrically when the gyro tilts. This produces precession torques that return the spin axis to the vertical. The erection system is what keeps the horizon bar aligned with the true horizon during coordinated flight.

Question 46Aircraft General Knowledge: Instruments and Electronics

What causes apparent drift of a gyroscope during flight over the Earth's surface?

  1. The change in static pressure inside the instrument case
  2. The magnetic variation at the aircraft's position
  3. The Earth's rotation transporting the gyro relative to inertial space Correct answer.
  4. The gyro rotor slowing down due to friction

Explanation

Apparent drift occurs because the gyro maintains its orientation in inertial space while the Earth rotates beneath it. To an observer on the Earth, the gyro appears to drift at a rate depending on latitude. Real drift, by contrast, is caused by friction and rotor imbalance.

Question 47Aircraft General Knowledge: Instruments and Electronics

A direct-reading magnetic compass is subject to turning error. When is this error greatest?

  1. When flying at high altitude in the northern hemisphere
  2. When turning through east or west on northerly or southerly headings Correct answer.
  3. When accelerating on an easterly heading
  4. When turning through north or south on easterly or westerly headings

Explanation

Turning error is largest when turning through east or west while the aircraft is on a northerly or southerly heading, because the compass card dips and the pivot geometry causes lag or lead. In the northern hemisphere the compass lags in a turn through north and leads in a turn through south. On east or west headings the error is small.

Question 48Aircraft General Knowledge: Instruments and Electronics

What is the function of the flux valve in a remote-indicating magnetic compass system?

  1. It detects the Earth's magnetic field and sends signals to the indicator Correct answer.
  2. It measures the rate of turn for the autopilot
  3. It converts static pressure into electrical altitude signals
  4. It provides the electrical power for the gyro rotor

Explanation

The flux valve senses the direction of the Earth's magnetic field and produces electrical signals proportional to the aircraft's heading relative to it. These signals are processed and displayed on the remote compass indicator. It does not drive the gyro or measure turn rate.

Question 49Aircraft General Knowledge: Instruments and Electronics

What does the red line on an airspeed indicator typically represent?

  1. The best rate-of-climb speed
  2. The maximum speed for flap extension
  3. The stall speed in the landing configuration
  4. The never-exceed speed (VNE) Correct answer.

Explanation

The red radial line marks VNE, the never-exceed speed, which must not be exceeded in any configuration or condition. The white arc marks the flap operating range and the green arc the normal operating range. The yellow arc between them indicates the caution range for smooth air only.

Question 50Aircraft General Knowledge: Instruments and Electronics

In a modern glass cockpit, what is the primary source of air data for the electronic flight instrument system?

  1. The attitude and heading reference system
  2. The engine indication and crew alerting system
  3. The air data computer processing pitot and static inputs Correct answer.
  4. The standby altimeter and standby airspeed indicator

Explanation

The air data computer receives pitot and static pressures and computes airspeed, altitude, vertical speed and temperature for display on the electronic flight instrument system. The standby instruments are independent backups, not the primary source. The attitude and heading reference system supplies attitude and heading, not air data.