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Pilot Exams · Subject guide

Aircraft General Knowledge Practice Questions for PPL, CPL and ATPL

Practise Aircraft General Knowledge for UCAA pilot exams: airframes, engines, fuel, electrics, hydraulics and systems, with explained answers and mock exams.

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By Ariguma Aviation editorial team · Published · Last reviewed

What Aircraft General Knowledge covers

Aircraft General Knowledge (AGK) explains how the aircraft itself works. It covers the structure that carries the loads, the engine that produces power, and the systems that keep fuel flowing, electricity available, controls responsive and occupants comfortable. Helicopter candidates also study rotor systems and transmissions. The aim is not to make you an engineer but to make you a pilot who understands the machine well enough to operate it within its limits and handle a failure calmly.

Why it matters operationally

Many in-flight problems begin as a systems issue: a rough-running engine, a falling oil pressure, a generator warning or ice building on the airframe. A pilot who understands the system can interpret the symptoms, choose the right checklist and judge what still works. Good systems knowledge also feeds directly into preflight inspections, fuel management and sensible use of engine controls.

How the emphasis changes from PPL to ATPL

UCAA lists Aircraft General Knowledge for the PPL, CPL and ATPL. PPL questions centre on light-aircraft piston engines, simple electrics, fuel systems and basic airframe knowledge. CPL questions go further into variable-pitch propellers, retractable gear and more complex systems. At ATPL level the subject reflects transport aircraft: turbine engines, pressurisation, hydraulic redundancy, ice protection and fire protection systems.

Common difficulties

  • Abstract systems. Without a picture, a fuel or hydraulic system is hard to follow. Diagrams help enormously.
  • Cause and effect. Many questions ask what happens next after a failure, which requires understanding rather than recall.
  • Terminology. Similar terms such as anti-icing and de-icing, or alternator and generator, are easy to confuse.

How to practise

Use Ariguma study mode to take one system at a time, reading the explanation for each question and sketching the system as you go. Ariguma has separate aeroplane and helicopter AGK banks at PPL, CPL and ATPL level. Once a system makes sense, mix topics so that you learn to switch between them as the exam will require. Finish with timed mock exams to confirm your pace. Ariguma practice is study material, not an official UCAA examination.

What Aircraft General Knowledge covers

  • Airframe and structures

    Fuselage, wing and tail construction, materials, loads and structural limitations.

  • Flight controls

    Primary and secondary controls, trim systems and how control inputs reach the control surfaces.

  • Piston engines

    The four-stroke cycle, carburation and fuel injection, ignition, lubrication and cooling.

  • Turbine engines

    Turbojet, turbofan, turboprop and turboshaft principles and their operating limitations.

  • Propellers and rotor systems

    Fixed and variable-pitch propellers and, for helicopters, main and tail rotor systems.

  • Fuel systems

    Fuel types, tank layouts, feed and crossfeed, contamination and the risk of carburettor icing.

  • Electrical systems

    Batteries, generators and alternators, buses, circuit protection and electrical failures.

  • Hydraulic and pneumatic systems

    How pressurised fluid and air are used to operate landing gear, brakes and controls.

  • Landing gear, brakes and tyres

    Gear configurations, retraction systems, braking and tyre care.

  • Environmental, ice and fire protection

    Pressurisation, air conditioning, de-icing and anti-icing, and fire detection and extinguishing.

How to revise Aircraft General Knowledge

  1. Draw each system as a simple flow diagram from source to user, then mark where a failure would show up in the cockpit.
  2. Use the pilot's operating handbook for the aircraft you fly as a real-world example of each system.
  3. For every system, ask what the warning looks like, what the pilot should do, and what still works afterwards.
  4. Group engine questions by cycle stage so you can see how a fault in one stage affects the others.

Frequently asked questions

Is Aircraft General Knowledge examined at every licence level?

Yes. UCAA advisory circular AC-PEL018 lists Aircraft General Knowledge as a knowledge subject for the PPL, CPL and ATPL.

Do I need an engineering background for this subject?

No. The subject explains systems from a pilot's point of view: how they work, how they fail and how you manage them. A logical approach and good diagrams matter more than prior engineering study.

Are there separate aeroplane and helicopter questions?

Yes. Ariguma has separate aeroplane and helicopter Aircraft General Knowledge banks at PPL, CPL and ATPL level, so helicopter candidates practise rotor and transmission topics.

Sources and official references

  1. CAA-AC-PEL018: Knowledge Testing for a Licence or RatingUganda Civil Aviation Authority · September 2022 · checked 2026-10-06

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