All exams ← Home
Home · PPL Aircraft General Knowledge Prep

PPL Aircraft General Knowledge Prep

Engines, electrics, instruments and airframes.

Written against the published specification.

See all-access plans
Pass mark 12/16 45 minutes UK CAA How many can I get wrong?
About this practice. Revision Robin is built and maintained by Bloor Engineering Ltd, a UK-registered company. Our PPL Aircraft General Knowledge Prep questions are written and reviewed in-house to match the current syllabus, each with a plain-English worked explanation. They are original practice material, not the official exam questions and not affiliated with or endorsed by UK CAA. Always confirm current test rules, fees and content with the official provider. See our Terms and Privacy.
Little and often beats one big session. Five minutes on the bus counts.
Free practice questions
Try 3 real PPL Aircraft General Knowledge Prep questions
Have a go, then reveal the worked explanation. A taster from a bank of 220 original questions. Unlock for unlimited drills and full timed mocks.
Q1. What type of fuselage construction relies on a framework of longitudinal and diagonal members, with the outer skin carrying little or no structural load?
  • A.  Truss (framework) construction
  • B.  Semi-monocoque construction
  • C.  Monocoque construction
  • D.  Geodetic construction
Show answer & explanation
✓ Answer: A. Truss (framework) construction
Truss construction uses welded steel tube or wooden frameworks to carry the loads, with fabric or thin skin simply providing an aerodynamic covering. In semi-monocoque and monocoque designs the skin itself is a primary load-bearing member, which is the key distinction examiners test for.
Q2. Most light aircraft piston engines have two independent magneto ignition systems, each firing its own spark plug in every cylinder. What is the main reason for this?
  • A.  It doubles the engine's power output
  • B.  It provides redundancy so the engine keeps running if one system fails, and improves combustion
  • C.  It allows the pilot to run the engine on half power for training
  • D.  It reduces the engine's fuel consumption by half
Show answer & explanation
✓ Answer: B. It provides redundancy so the engine keeps running if one system fails, and improves combustion
Dual magnetos give redundancy — if one fails or is switched off the other keeps the engine running, which is why the run-up check confirms both work. Firing two plugs per cylinder also gives a more complete, even burn, but it does not double power output or halve fuel burn.
Q3. What is detonation in a piston aero engine, and why is it dangerous?
  • A.  Normal, controlled burning of the fuel-air mixture that simply happens faster than usual
  • B.  Uncontrolled, explosive combustion of the remaining mixture after normal ignition, causing damaging pressure spikes
  • C.  A backfire through the induction system caused by a rich mixture at idle
  • D.  The sound made by the exhaust valve closing under high RPM
Show answer & explanation
✓ Answer: B. Uncontrolled, explosive combustion of the remaining mixture after normal ignition, causing damaging pressure spikes
Detonation is an abnormal, near-instantaneous explosion of the unburned end-gas after normal spark ignition has started the burn, producing sharp pressure spikes that can damage pistons, rings and cylinder heads. It is not the same as a controlled burn, an induction backfire, or a mechanical valve noise.
Exam mode
Full mock exam
16 random questions, real timing, marked against the official pass mark. Different every time.
The first 8 of 16 questions are free, with your score on them. Finishing the paper, your result against the pass mark and every answer explained come with the paid version.
Practice material only. This is revision practice, not official training, assessment or certification, and not a substitute for the required course or supervised experience. Always confirm the current requirements with the official awarding body or test provider before relying on it.
Try it free
Topic drills
Ten quick questions on one topic, marked instantly with explanations.
1 free drill left.
Airframes & structures · 37
Piston engines & propellers · 35
Fuel, oil & cooling systems · 40
Electrics, ignition & avionics basics · 35
Pressure instruments & gyros · 37
The compass & instrument errors · 36

Who has to sit the PPL Aircraft General Knowledge Prep

Who needs a PPL Aircraft General Knowledge Prep?

All UK Private Pilot Licence (PPL) students.

The real PPL Aircraft General Knowledge Prep: format

How many questions are in the PPL Aircraft General Knowledge Prep?

The real PPL Aircraft General Knowledge Prep has 16 questions and lasts 35 minutes. Our mock uses 16 questions in 45 minutes.

What is the PPL Aircraft General Knowledge Prep pass mark?

Real exam pass mark: 75%. Our mock marks you at 12 out of 16, the threshold we mark against.

What it costs, and what a resit costs

How much does the PPL Aircraft General Knowledge Prep cost?

Real exam fee: £30-£60 per sitting. Rebooking after a fail: Max 4 attempts per subject. 4th failure requires further training, 3-month cooling-off, and all prior passes void.

How hard is it

How hard is the PPL Aircraft General Knowledge Prep?

Difficulty: Medium; simpler than Navigation but requires understanding beyond memorization.

Figures for the real exam from vertexaisearch.cloud.google.com, checked October 2026. Fees and rules change, so confirm with the test provider before you book.
PPL Aircraft General Knowledge Prep: common questions
Frequently asked
How long do you get?
The test is timed at 45 minutes. Our full mock runs on the same clock so you can practise your pacing.
Are these the real exam questions?
No. Our questions are original and written to match the current syllabus, so they give realistic practice without copying the official paper. Every answer comes with a plain-English explanation. Always confirm current rules and content with UK CAA.