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ICAA PPL Theory study materials
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ICAA PPL Theory practice questions

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Question 1Air Law

Under ICAO Annex 2, when must a pilot-in-command display anticollision lights on an aircraft in flight?

  1. Only when operating in controlled airspace
  2. At all times, unless the pilot considers it inadvisable for safety Correct answer.
  3. Only when the aircraft is being refuelled
  4. Only between sunset and sunrise

Explanation

Annex 2 requires that aircraft in flight display anticollision lights, and the rule is continuous rather than tied to daylight or airspace class. The pilot may switch them off when conditions such as fog or haze make them a hazard to safety.

Question 2Air Law

Which document is the primary source of international standards and recommended practices for licensing of flight crew?

  1. ICAO Annex 6
  2. ICAO Annex 11
  3. ICAO Annex 1 Correct answer.
  4. ICAO Annex 8

Explanation

Annex 1, Personnel Licensing, sets out the international standards for flight crew licences, ratings, medical fitness and recency. Annex 6 covers operation of aircraft and Annex 8 covers airworthiness, so neither governs licence standards.

Question 3Air Law

In the standard ICAO phonetic alphabet, which word represents the letter Q?

  1. Quebec Correct answer.
  2. Quota
  3. Quincy
  4. Quasar

Explanation

The ICAO spelling alphabet assigns Quebec to the letter Q. The other words are not part of the standard alphabet and would not be understood by controllers as a letter designator.

Question 4Air Law

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

  1. Continue circling and await further instructions
  2. Give way to other aircraft and continue circling Correct answer.
  3. Return for landing, a clearance to land will follow
  4. Land and proceed to the apron

Explanation

A steady red light shown to an aircraft in flight instructs the pilot to give way to other traffic and continue circling. A steady red light shown on the ground means stop, which is a different meaning and context.

Question 5Air Law

An aircraft is on a converging course with another aircraft of the same category at approximately the same level. Which aircraft has the right of way?

  1. The aircraft on the right Correct answer.
  2. The aircraft on the left
  3. The aircraft that transmits its position first
  4. The faster aircraft

Explanation

When two aircraft of the same category converge at approximately the same level, the aircraft on the right has the right of way. The other aircraft must give way, and speed or radio calls do not alter this rule.

Question 6Air Law

Which of the following correctly describes a 'prohibited area' as established under national air law?

  1. An area where flight is permitted only with prior ATC clearance
  2. An area within which flight is forbidden at all times Correct answer.
  3. An area where flight is permitted only during published hours
  4. An area where flight is subject to seasonal restrictions

Explanation

A prohibited area is airspace within which flight is forbidden, typically for security or safety reasons, and no clearance makes entry lawful. Restricted areas allow flight under specified conditions, and danger areas merely warn of hazards.

Question 7Air Law

For a flight conducted under visual flight rules in Class C airspace, what is required before entry?

  1. No requirement, because VFR flight is free in Class C
  2. A position report on the area frequency only
  3. A clearance from the controlling ATC unit Correct answer.
  4. Prior permission from the aerodrome operator only

Explanation

Class C airspace requires an ATC clearance for all flights, including VFR, and the aircraft must be equipped and the pilot qualified for that airspace. A position report or operator permission does not substitute for the clearance.

Question 8Air Law

Which body issues the Standards and Recommended Practices that form the basis of international air law?

  1. IATA
  2. ICAO Correct answer.
  3. EASA
  4. AOPA

Explanation

ICAO, a specialised agency of the United Nations, adopts Standards and Recommended Practices in its Annexes to the Chicago Convention. IATA is an airline trade association, EASA is a regional regulator, and AOPA represents aircraft owners and pilots.

Question 9Air Law

An aircraft is being overtaken by another aircraft. Which aircraft must keep clear?

  1. The aircraft flying at the higher altitude
  2. The overtaking aircraft Correct answer.
  3. The aircraft being overtaken
  4. The aircraft with the lower maximum take-off mass

Explanation

The overtaking aircraft must keep out of the way of the aircraft being overtaken, whether climbing, descending or level, until it is entirely past and clear. Altitude and mass do not reverse this duty.

Question 10Air Law

What is the validity period of a Class 1 medical certificate for a private pilot licence holder under 40 years of age who is not conducting commercial operations?

  1. 24 months Correct answer.
  2. 12 months
  3. 60 months
  4. 6 months

Explanation

For a PPL holder under 40 engaged in non-commercial operations, the Class 1 medical certificate is valid for 24 months from the date of examination. Commercial operations with a Class 1 certificate shorten the validity to 12 months.

Question 11Air Law

An aircraft radio fails in controlled airspace while flying under VFR. The pilot should:

  1. Squawk 7600, remain VFR and land as soon as practicable at a suitable aerodrome Correct answer.
  2. Continue as planned and report the failure after landing
  3. Turn back to the departure aerodrome without notifying anyone
  4. Squawk 7700 and climb to the highest available level

Explanation

The radio failure code is 7600, and a VFR pilot who cannot maintain two-way communication should stay clear of controlled airspace unless special arrangements apply, then land as soon as practicable. Squawking 7700 signals an emergency, which a radio failure alone does not necessarily constitute.

Question 12Air Law

Which transponder code indicates unlawful interference with an aircraft?

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

Explanation

7500 is the special code for unlawful interference, 7600 for radio failure and 7700 for emergency. 7000 is the standard conspicuity code used in many regions when no other code is assigned.

Question 13Air Law

A pilot wishes to operate a flight into an aerodrome within Class D airspace. Which statement about VFR entry is correct?

  1. Entry is permitted only if the aircraft is IFR equipped
  2. Entry requires a clearance, and ATC provides traffic information on IFR and VFR flights Correct answer.
  3. Entry requires only that the pilot monitor the frequency
  4. Entry is permitted without any communication

Explanation

Class D requires an ATC clearance for VFR entry, and the controller provides traffic information about IFR and VFR flights. Monitoring without a clearance, or entering without communication, is not permitted.

Question 14Air Law

What does the abbreviation 'ATZ' denote in air law?

  1. Aircraft transit zone
  2. Air traffic zone
  3. Approach transition zone
  4. Aerodrome traffic zone Correct answer.

Explanation

ATZ stands for aerodrome traffic zone, the airspace around an aerodrome established to protect aerodrome traffic. Pilots must comply with the specific rules for entry and radio contact applicable to that zone.

Question 15Air Law

During an approach to land, when may a pilot descend below the decision altitude on an instrument approach?

  1. When the runway is reported as wet
  2. When the required visual reference has been established Correct answer.
  3. When cleared by the tower to land
  4. When the aircraft is stabilised on the approach

Explanation

Descent below the decision altitude on an instrument approach is permitted only once the required visual reference has been established and the aircraft is positioned to continue safely. A landing clearance or a stabilised approach alone does not permit descent below minima.

Question 16Air Law

Which of these is a recommended practice rather than a standard under the ICAO Annexes?

  1. Display of anticollision lights on aircraft in flight
  2. Carriage of a first-aid kit in aircraft Correct answer.
  3. Compliance with the rules of the air over the high seas
  4. Licensing of aircraft maintenance engineers

Explanation

A Recommended Practice is desirable but not mandatory, and carriage of a first-aid kit is commonly framed that way in the Annexes. Standards, by contrast, are mandatory for contracting states unless they file a difference.

Question 17Air Law

A pilot is uncertain of their position and has limited fuel. What is the correct priority according to the rules of the air?

  1. Turn back to the departure aerodrome regardless of fuel
  2. Land at the nearest suitable aerodrome and inform ATC Correct answer.
  3. Climb to the highest available level and hold
  4. Continue to the destination and report on arrival

Explanation

A pilot who is uncertain of position or short of fuel should declare the situation and land at the nearest suitable aerodrome, informing ATC. Continuing or holding wastes fuel and increases risk, and the priority is safety of the aircraft and occupants.

Question 18Air Law

What is the meaning of the term 'ceiling' in aviation meteorology as used for flight planning?

  1. The height of the highest cloud layer
  2. The altitude of the tropopause
  3. The maximum altitude of the aircraft
  4. The height above ground of the lowest cloud layer covering more than half the sky Correct answer.

Explanation

Ceiling is the height above ground of the lowest layer of cloud that is broken or overcast. A scattered or few layer does not constitute a ceiling, and the tropopause or aircraft maximum altitude are unrelated concepts.

Question 19Air Law

Under ICAO rules, what is the minimum horizontal separation standard applied by ATC between aircraft at the same level in radar-controlled airspace?

  1. 5 nautical miles Correct answer.
  2. 3 nautical miles
  3. 10 nautical miles
  4. 15 nautical miles

Explanation

In radar-controlled airspace the standard minimum horizontal separation is 5 nautical miles, unless reduced separation minima are specifically authorised. 3 nautical miles applies only where approved for certain terminal operations.

Question 20Air Law

What is the correct action when a pilot receives a clearance that they cannot comply with?

  1. Request an amended clearance and state the reason Correct answer.
  2. Squawk 7700 immediately
  3. Read back the clearance and comply as far as possible
  4. Ignore the clearance and continue on the current heading

Explanation

A pilot who cannot accept a clearance must advise ATC and request an amended clearance, explaining the reason. Reading back a clearance implies acceptance, and ignoring it or declaring an emergency is not appropriate for a routine inability to comply.

Question 21Air Law

Which of the following best describes a 'danger area' on an aeronautical chart?

  1. Airspace where activities dangerous to flight may exist and pilots should exercise caution Correct answer.
  2. Airspace reserved exclusively for military operations
  3. Airspace within which flight is prohibited
  4. Airspace requiring prior permission from the controlling authority

Explanation

A danger area warns of activities that may be hazardous to flight, such as gunnery or parachuting, and pilots should exercise caution or avoid it when active. It is not prohibited airspace and does not require a clearance.

Question 22Air Law

What is the purpose of the 'read-back' requirement for ATC clearances?

  1. To reduce the need for radio communication later
  2. To allow ATC to record the transmission for billing
  3. To confirm the pilot has copied the clearance correctly Correct answer.
  4. To confirm the pilot's licence details

Explanation

Read-back ensures the pilot has correctly received and understood safety-related clearances and instructions, allowing ATC to detect and correct errors. It is a safety barrier, not an administrative or billing measure.

Question 23Air Law

An aircraft is landing and another is on final approach behind it. Which aircraft has priority?

  1. The aircraft that first calls the tower
  2. The aircraft with the higher approach speed
  3. The lower aircraft Correct answer.
  4. The aircraft on final approach at the greater distance

Explanation

For aircraft on final approach to land, the lower aircraft has the right of way, and the higher aircraft must give way. This applies even if the higher aircraft is closer to the threshold or calls first.

Question 24Air Law

Which of these is required for an aircraft operating under IFR in controlled airspace at night?

  1. A second pilot on board
  2. A clearance to fly VFR on top
  3. A serviceable landing light only
  4. Adequate navigation equipment and an instrument rating for the pilot Correct answer.

Explanation

IFR flight in controlled airspace requires suitable navigation equipment and a pilot holding the appropriate instrument qualification. A landing light or a second pilot may be operationally useful but are not the general legal requirement.

Question 25Air Law

A pilot files a flight plan and then delays departure by 45 minutes. What is the usual requirement regarding the flight plan?

  1. The flight plan is automatically cancelled
  2. The pilot must refile only if the delay exceeds 60 minutes
  3. No action is needed as long as the flight is completed
  4. The flight plan should be amended or a new one filed Correct answer.

Explanation

When departure is delayed beyond the period allowed by the flight plan rules, the pilot should amend the flight plan or file a new one so that search and rescue and ATC information remain accurate. Silence can cause unnecessary alerting action.

Question 26Air Law

Under the ICAO Convention on International Civil Aviation, what is the status of the Standards and Recommended Practices (SARPs) adopted by the Council?

  1. They apply only to aircraft engaged in commercial air transport.
  2. They are advisory only and have no legal force.
  3. They are binding on contracting states unless a state files a difference. Correct answer.
  4. They are binding on all contracting states without exception.

Explanation

Article 37 of the Chicago Convention requires each contracting state to collaborate in securing the highest practicable degree of uniformity in regulations. Article 38 allows a state that finds it impracticable to comply with any international standard to notify ICAO of the difference, so the standard is not binding on that state to the extent of the notified difference. Recommended practices are not mandatory in the same way, and SARPs apply to international civil aviation generally, not only to commercial operations.

Question 27Air Law

An aircraft is on a runway when another aircraft on final approach receives a landing clearance. Which aircraft has the right of way?

  1. The aircraft on the runway, because it is already on the movement area.
  2. The aircraft that is faster.
  3. The aircraft on final approach, because it is landing. Correct answer.
  4. The aircraft that is lower on approach.

Explanation

Under the rules of the air, an aircraft on final approach to land has the right of way over other aircraft. An aircraft that is on the runway but not yet airborne is not on final approach and must give way, for example by vacating or by not entering the runway if the approaching aircraft is on final. The other options do not reflect any right-of-way rule.

Question 28Air Law

In which situation is a pilot required to file a flight plan before departure?

  1. When flying VFR within controlled airspace in daylight.
  2. When flying VFR in Class G airspace.
  3. When flying an international flight. Correct answer.
  4. When flying a local training flight within 10 NM of the aerodrome.

Explanation

A flight plan must be filed for any flight across international borders, and for other flights as specified by the state, such as IFR flights in controlled airspace or flights in designated areas. Domestic VFR flights in controlled airspace or Class G do not automatically require a flight plan unless local rules say so. Local training flights near the aerodrome are typically exempt.

Question 29Air Law

An aircraft is being intercepted by a military aircraft. According to ICAO procedures, what should the intercepted pilot do first?

  1. Climb immediately to the highest available altitude.
  2. Turn away from the intercepting aircraft and increase speed.
  3. Attempt to establish radio communication with the intercepting aircraft and comply with its instructions. Correct answer.
  4. Squawk 7700 and continue on the current heading.

Explanation

ICAO Annex 2 requires the pilot of an intercepted aircraft to attempt to establish radio communication with the intercepting aircraft or with the appropriate air traffic control unit, and to comply with instructions given. The pilot should also squawk 7700 if instructed, but the first action is to establish communication and follow the interceptor's signals. Climbing, turning away, or continuing without communication could be misinterpreted.

Question 30Air Law

An aircraft is flying under VFR in Class E airspace. What is the minimum flight visibility required for the flight to be conducted legally?

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

Explanation

Under ICAO Annex 2, for VFR flights in Class E airspace at and above 3 050 m (10 000 ft) AMSL, the flight visibility must be at least 8 km; below that level, the minimum flight visibility is 5 km. Since the question does not specify an altitude above 3 050 m, the general minimum of 5 km applies. The other values are either too low or apply to different airspace or altitude conditions.

Question 31Aircraft General Knowledge

In a four-stroke aircraft piston engine, which stroke immediately follows the power (combustion) stroke?

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

Explanation

The four strokes occur in the fixed order intake, compression, power and exhaust. After the burning mixture has driven the piston down on the power stroke, the exhaust valve opens and the piston rises to expel the gases. Induction is simply another name for the intake stroke, so it cannot follow the power stroke.

Question 32Aircraft General Knowledge

What is the primary function of the magneto in a piston aero-engine ignition system?

  1. To cool the spark plug electrodes between firings
  2. To generate the high-tension voltage that fires the spark plugs Correct answer.
  3. To drive the vacuum pump for the gyro instruments
  4. To regulate the fuel-air mixture strength

Explanation

A magneto is a self-contained generator that produces high voltage for the spark plugs without relying on the aircraft battery. Because it is driven by the engine and has its own magnetic circuit, it keeps firing even if the electrical system fails. Fuel metering, plug cooling and vacuum supply are functions of other systems entirely.

Question 33Aircraft General Knowledge

Why is the fuel-air mixture in a normally aspirated engine kept slightly rich at high power settings?

  1. To reduce the mass of air entering the cylinders
  2. To prevent the spark plugs from fouling at high rpm
  3. To provide excess fuel for internal cooling and to avoid detonation Correct answer.
  4. To increase the octane rating of the fuel as it enters the cylinder

Explanation

A richer-than-stoichiometric mixture burns more slowly and evaporates extra fuel that absorbs heat, lowering peak combustion and cylinder-head temperatures. This protects the engine from detonation and pre-ignition at high power. The mixture setting cannot alter the fuel's octane rating or the mass of air drawn in.

Question 34Aircraft General Knowledge

An engine's oil pressure gauge reads zero in flight with the engine still running. What is the most appropriate immediate action?

  1. Continue to the destination while monitoring the gauge
  2. Reduce power and land as soon as practicable, preparing for possible engine failure Correct answer.
  3. Increase power to raise oil pressure
  4. Switch off the magnetos to stop the engine

Explanation

Loss of oil pressure means the engine is no longer being lubricated or cooled adequately and may seize or fail at any moment. The pilot should reduce power to lessen load and heat, plan an immediate precautionary landing and be ready for a forced landing. Continuing or increasing power accelerates damage, and shutting down the engine in flight is not the first response.

Question 35Aircraft General Knowledge

What does the tachometer in a light aircraft indicate?

  1. Cylinder head temperature
  2. Engine crankshaft rotational speed Correct answer.
  3. Manifold absolute pressure
  4. Fuel flow rate

Explanation

The tachometer displays engine speed, usually in revolutions per minute, so the pilot can keep within the limits set in the flight manual. Manifold pressure, temperature and fuel flow are shown by separate dedicated gauges. Confusing these instruments can lead to incorrect power setting.

Question 36Aircraft General Knowledge

Which statement correctly describes the purpose of the carburettor heat control?

  1. It warms the fuel before it reaches the float chamber
  2. It heats the engine oil during start-up
  3. It raises the temperature of the cabin air supply
  4. It supplies warmed air to the induction system to prevent or clear carburettor icing Correct answer.

Explanation

Carburettor heat directs air through a shroud around the exhaust or a heat exchanger before it enters the carburettor. The warmed air melts ice that forms in the venturi and prevents further build-up. It does not heat the fuel, the oil or the cabin.

Question 37Aircraft General Knowledge

During a magneto check, an aircraft engine runs roughly and shows a large rpm drop when switched to the left magneto. What does this most likely indicate?

  1. Normal operation of the left magneto
  2. A blocked fuel vent
  3. An overfilled oil sump
  4. A fault in the left magneto circuit or its spark plugs Correct answer.

Explanation

When only the left magneto is selected, the engine runs on that magneto alone. Excessive roughness or a large rpm drop points to a problem in that magneto or its associated plugs and leads. Normal operation produces only a small, smooth drop within the flight manual limits.

Question 38Aircraft General Knowledge

Why is a constant-speed propeller more efficient than a fixed-pitch propeller across a wide range of speeds?

  1. It always turns at a lower rpm than a fixed-pitch unit
  2. It maintains an efficient blade angle for the prevailing airspeed and rpm Correct answer.
  3. It removes the effect of density altitude on power
  4. It eliminates the need for a throttle

Explanation

A constant-speed unit automatically changes blade angle so the propeller keeps an efficient angle of attack as airspeed and power vary. This lets the engine run at a selected rpm while thrust is optimised. It does not remove the throttle, guarantee lower rpm, or cancel density altitude effects.

Question 39Aircraft General Knowledge

Which of the following is a consequence of operating an engine with the mixture excessively lean at high power?

  1. Increased fuel consumption
  2. Lower cylinder head temperatures and reduced wear
  3. Automatic enrichment by the carburettor
  4. Rising cylinder head temperatures and risk of detonation Correct answer.

Explanation

A very lean mixture burns at higher peak temperatures and pressures, raising cylinder head temperature and making detonation more likely. This can damage valves and pistons. Lean operation reduces rather than increases fuel consumption, and a simple carburettor does not enrich itself to compensate.

Question 40Aircraft General Knowledge

What is the function of the voltage regulator in an aircraft electrical system?

  1. To limit the current drawn by the starter motor
  2. To hold the generator or alternator output voltage within limits Correct answer.
  3. To convert alternating current to direct current
  4. To protect the battery from over-discharge on the ground

Explanation

The voltage regulator controls the field current so the generator or alternator output stays at the design voltage despite changing rpm and load. This protects the battery and avionics from over-voltage. Rectification, battery protection and starter current limiting are handled by other components.

Question 41Aircraft General Knowledge

An ammeter shows a continuous high charge rate shortly after start, which does not fall back as the flight continues. What is the most likely interpretation?

  1. The battery is not accepting charge or the regulator is faulty Correct answer.
  2. The alternator has failed completely
  3. The battery is fully charged and normal
  4. The ammeter is reading engine rpm

Explanation

A high charge rate is normal briefly after start to replace the energy used by the starter, but it should taper as the battery recharges. A sustained high reading suggests the battery is not accepting charge or the regulator is over-driving the alternator. A failed alternator would show a discharge, not a high charge.

Question 42Aircraft General Knowledge

What is the purpose of the engine air filter on an aircraft with a carburettor?

  1. To separate water from the fuel
  2. To prevent dust and foreign matter entering the induction system Correct answer.
  3. To cool the incoming charge
  4. To silence the exhaust note

Explanation

The air filter traps dust, sand and other debris before the air reaches the carburettor, protecting the engine from abrasion and blockage. It does not cool the charge, quieten the exhaust or affect the fuel system. Many aircraft provide an alternate air source in case the filter ices or blocks.

Question 43Aircraft General Knowledge

Why must carburettor heat be applied with care when the engine is developing high power?

  1. Warmed induction air is less dense, so it reduces power output Correct answer.
  2. It enriches the mixture beyond limits
  3. It increases the octane rating of the fuel
  4. It causes the propeller to overspeed

Explanation

Heated air expands and becomes less dense, so each intake stroke draws in fewer oxygen molecules and power falls. The effect is noticeable at high power and full throttle. Carburettor heat does not change fuel octane, drive propeller overspeed or directly enrich the mixture.

Question 44Aircraft General Knowledge

What is the main reason an aircraft engine uses a dry-sump lubrication system?

  1. To lubricate only the propeller hub
  2. To eliminate the need for an oil cooler
  3. To store oil in a separate tank and allow the pump to scavenge oil from the engine Correct answer.
  4. To mix oil directly with the fuel

Explanation

In a dry-sump system oil is carried in a separate tank, a pressure pump feeds the engine and a scavenge pump returns oil to the tank. This avoids oil surging in the sump during manoeuvres and allows a compact engine. It does not mix oil with fuel or remove the need for cooling.

Question 45Aircraft General Knowledge

What does a rising cylinder head temperature in cruise, with mixture and power unchanged, most likely suggest?

  1. A richer mixture than set
  2. Inadequate cooling airflow or a baffle problem Correct answer.
  3. A failed fuel gauge
  4. A normal seasonal variation

Explanation

With power and mixture fixed, a rising CHT points to reduced cooling, such as blocked or damaged baffles, a low airspeed or high outside air temperature. The pilot should check cowl flaps, airspeed and engine parameters. A richer mixture would tend to lower CHT, and a fuel gauge fault is unrelated.

Question 46Aircraft General Knowledge

Which component converts the reciprocating motion of the pistons into rotary motion of the crankshaft?

  1. Valve springs
  2. Connecting rods Correct answer.
  3. Magneto points
  4. Pushrods

Explanation

The connecting rods link each piston to a crankpin on the crankshaft. As the piston moves up and down, the rod swings and turns the crankshaft, converting reciprocating motion into rotation. Valve springs, pushrods and magneto points serve the valve train and ignition respectively.

Question 47Aircraft General Knowledge

What is meant by the compression ratio of a piston engine?

  1. The ratio of cylinder volume before compression to that after compression Correct answer.
  2. The ratio of engine rpm to propeller rpm
  3. The ratio of fuel to air by mass
  4. The ratio of oil pressure to manifold pressure

Explanation

Compression ratio compares the total cylinder volume with the piston at the bottom of its stroke to the clearance volume with the piston at the top. A higher ratio gives greater thermal efficiency but raises detonation risk. It is unrelated to mixture strength, gearing or pressure readings.

Question 48Aircraft General Knowledge

Why does an engine with a fixed-pitch propeller tend to overspeed in a descent at high power?

  1. Oil pressure rises and drives the propeller faster
  2. The mixture automatically leans in the descent
  3. The magnetos advance the timing beyond limits
  4. Airspeed increases and the propeller blade angle cannot adjust to absorb the extra energy Correct answer.

Explanation

With a fixed blade angle, a rise in airspeed reduces the propeller's angle of attack and lets it turn faster, so rpm can exceed limits unless power is reduced. A constant-speed propeller would increase blade angle to hold rpm. Mixture, ignition timing and oil pressure do not drive this effect.

Question 49Aircraft General Knowledge

What is the function of the exhaust gas temperature gauge in mixture management?

  1. It measures the oil temperature at the cooler
  2. It helps identify the mixture setting that gives peak EGT so the pilot can enrich or lean from that point Correct answer.
  3. It indicates cylinder head temperature directly
  4. It shows the temperature of the cabin heater

Explanation

As the mixture is leaned, EGT rises to a peak and then falls. The pilot uses this peak as a reference and then enriches or leans by a specified amount for the desired power setting. The gauge does not measure cabin heat, cylinder head or oil temperature.

Question 50Aircraft General Knowledge

Which statement best explains why detonation is dangerous to an aero-engine?

  1. The charge fails to ignite at all
  2. The charge burns explosively after normal ignition, causing pressure spikes and high temperatures Correct answer.
  3. The spark occurs too early and the engine stops
  4. The fuel freezes in the carburettor

Explanation

Detonation occurs when the end gas ignites spontaneously after the spark, producing violent pressure oscillations and very high temperatures that can crack pistons and damage bearings. It differs from pre-ignition, where the charge lights before the spark. Failure to ignite or fuel freezing are separate problems.