PPL Aircraft General Knowledge exam

What the exam covers

Pocket Pilot teaches Aircraft General Knowledge in eight lessons, about 38 minutes of reading in all.

1. 01

   Airframe & Flight Controls

   5 min

   The three primary controls · Secondary controls and trim · Adverse yaw · Undercarriage, wheels and brakes · Load factor and the V-n diagram

2. 02

   The Four-Stroke Piston Engine

   11 min

   The Otto cycle: four strokes, two revolutions · Why horizontally opposed? · Dual ignition: two magnetos, two spark plugs per cylinder · The magneto check · Operating instruments · Engine cooling · The oil system · Detonation and pre-ignition · Power and altitude: naturally aspirated · Turbocharging: a different story · Engine handling fundamentals · Time Between Overhaul (TBO)

3. 03

   Fuel Systems, Carburettor & Mixture

   4 min

   Aviation fuel grades · Fuel delivery: gravity vs pump feed · Fuel contamination · The carburettor · Fuel injection · Mixture control

4. 04

   Propellers

   5 min

   Geometry · Fixed-pitch propellers · Variable-pitch / constant-speed propellers · Critical handling rules · Propeller efficiency · Asymmetric blade effect ("P-factor") · The critical engine (twins) · Propeller hazards on the ground

5. 05

   Pitot-Static Instruments

   3 min

   The two pressures · The altimeter · The Vertical Speed Indicator (VSI) · The Airspeed Indicator (ASI) · Blockage failure modes

6. 06

   Gyroscopic Instruments

   4 min

   Two fundamental properties · The Attitude Indicator · The Heading Indicator (Directional Gyro) · The Turn Coordinator · Vacuum-system failure · Modern alternatives: AHRS and EFIS

7. 07

   The Magnetic Compass

   3 min

   How it works · Variation · Deviation · Acceleration / deceleration errors (ANDS) · Turning errors (UNOS) · When to read the compass

8. 08

   Electrical System

   3 min

   The major components · Why an alternator, not a generator? · Charging and the ammeter / loadmeter · Alternator failure in flight · Circuit breakers and electrical fires

How the exam works

Aircraft General Knowledge is one of the nine PPL(A) theory exams. Each is a separate multiple-choice paper, sat at your school or at a test centre approved by your national aviation authority. This one has 16 questions in 35 minutes, and you need 75% to pass, which is 12 correct answers.

• You have four attempts at each subject before further training is required.
• You must pass all nine within 18 months of your first sitting, in no more than six sittings.
• Your passes then stay valid for 24 months, and your skill test must fall inside that window.

The Aircraft General Knowledge mock exam in Pocket Pilot has the same question count, time limit and pass mark, drawn from a growing bank of practice questions.

Try three exam questions

From the Pocket Pilot Aircraft General Knowledge question bank, each with the app's explanation and the source it cites.

1. 01 / 03

   If the static port becomes blocked, which instruments will be affected?

   1. AOnly the airspeed indicator
   2. BAltimeter, vertical speed indicator, and airspeed indicator
   3. COnly the altimeter
   4. DOnly the vertical speed indicator
   Show the answerHide the answer

   Answer B. All three pitot-static instruments rely on static pressure: the altimeter, the vertical speed indicator, and the airspeed indicator. A blocked static port affects them all (use the alternate static source if fitted).

   Source

   EASA Subject 022 – Instruments (pitot-static system)

   Lesson

   Pitot-Static Instruments

2. 02 / 03

   With a fixed-pitch propeller, developing carburettor ice first shows as:

   1. AA gradual, unexplained loss of RPM, possibly with rough running
   2. BAn immediate rise in oil temperature
   3. CA drop in fuel pressure
   4. DThe mixture control moving by itself
   Show the answerHide the answer

   Answer A. Ice narrowing the venturi progressively strangles the mixture flow: RPM decays gradually (or manifold pressure, on a constant-speed installation), followed by rough running and eventually stoppage. Apply full carburettor heat: expect a further initial drop, then recovery as the ice melts.

   Source

   UK CAA Safety Sense Leaflet 14 (Piston Engine Icing)

   Lesson

   Fuel Systems, Carburettor & Mixture

3. 03 / 03

   Following a total electrical failure in flight, the engine of a light piston aircraft will:

   1. AStop immediately
   2. BContinue running normally, because the magnetos are independent of the electrical system
   3. CRun only at reduced power
   4. DContinue only while the battery lasts
   Show the answerHide the answer

   Answer B. The magnetos generate their own ignition current from engine rotation and need neither battery nor alternator. An electrical failure costs radios, some flaps and gear systems, and lighting, but never the ignition. The reverse implication: a propeller can fire whenever it is moved, so treat every prop as live.

   Source

   EASA Subject 021 (ignition)

   Lesson

   The Four-Stroke Piston Engine

The other eight exams

• Air Law→16 questions · 35 min
• Human Performance & Limitations→12 questions · 25 min
• Meteorology→16 questions · 50 min
• Communications→12 questions · 20 min
• Navigation→12 questions · 45 min
• Principles of Flight→12 questions · 35 min
• Operational Procedures→12 questions · 30 min
• Flight Performance & Planning→12 questions · 45 min