Part-66 Module 14 Propulsion Questions (B2 and B2L)

Part-66 Module 14 propulsion is the engine module for the avionics licence. If you are looking for Part-66 Module 14 questions, expect a short paper with a particular slant: it does not ask a B2 candidate to know compressor blade root fixings or bearing sump layouts, but it does expect you to know how a FADEC controls fuel, how an EGT harness averages its probes, how an EPR transmitter works and why an ignition exciter can kill you. This page gives the paper sizes under EASA and UK CAA rules, explains the real syllabus difference between the two systems, walks through every sub-module and ends with a study plan.

Part-66 Prep is an independent study aid, not EASA, the UK CAA or a Part-147 organisation. For how Module 14 fits with the other papers, see the Part-66 modules guide.

Module 14 paper size: EASA vs UK CAA

Category	EASA questions / time	UK CAA questions / time
B2	32 / 40 min	24 / 30 min
B2L (instruments or airframe systems rating)	32 / 40 min	24 / 30 min
A, B1, B3	not required	not required

Both are three-option multiple-choice papers with 75 seconds a question, a 75% pass mark, no negative marking and no essays. The EASA figures are from Appendix II as replaced by Regulation (EU) 2023/989; the UK figures are from the retained Appendix II on legislation.gov.uk.

Key fact: On the 24-question UK paper you need 18 correct; on the 32-question EASA paper you need 24. Either way you can afford six wrong answers at most on the UK paper and eight on the EASA one.

Who sits Module 14

Module 14 belongs to the B2 and B2L licences only. For the B2 licence it is one of two aircraft-specific modules, alongside the long Module 13. For the B2L licence it depends on the system ratings you choose: the instruments rating and the airframe systems rating include Module 14, while com/nav, autoflight and surveillance do not. If you hold a B2L with com/nav only and later add instruments, Module 14 is one of the exams you add.

B1 and category A candidates never sit Module 14. They study the engine in mechanical depth in Module 15 (gas turbine) or Module 16 (piston), and propellers in Module 17.

The EASA and UK Module 14 syllabus are not the same

This is the point most question banks miss. The EU rewrote Module 14 when it replaced Appendix I in 2024, and the UK kept the older version.

Sub-module	EASA (Appendix I, 2023/989)	UK CAA (retained Appendix I)
14.1	Engines: turbine (level 1), APU (1), piston (1), electric and hybrid (2), engine control and FADEC (2)	Turbine engines: types and arrangement (level 1), FADEC and fuel metering (2)
14.2	Electric and electronic engine indication (2)	Engine indicating systems (2)
14.3	Propeller systems (2)	Starting and ignition systems (2)
14.4	Starting and ignition systems (2)	not present

So a UK candidate does not need APUs, piston engines, electric and hybrid propulsion or a separate propeller systems sub-module, though propeller speed is part of the UK indication list. An EASA candidate does, and electric and hybrid propulsion is at level 2, the same depth as FADEC. If you study from a pre-2024 book for an EASA exam, the electric and hybrid content will be missing. If you study EASA material for a UK exam, you will spend time on topics that are not examined. The CAA's engineer knowledge requirements page links to the current UK text.

The EASA guidance on question spread (AMC1 to Appendix II) gives an idea of where the 32 marks sit: about 16 in 14.1 across its five topics, 10 in engine indication, 2 in propeller systems and 4 in starting and ignition. Indication is the single biggest block.

Sub-module 14.1: engines and engine control

Engine types at level 1

You need the arrangement and operating principle of the turbojet, turbofan, turboprop and turboshaft: all work on the Brayton cycle, the turbofan sends most of its air around the core (bypass ratio is bypass mass flow divided by core mass flow), the turboprop drives a propeller through a reduction gearbox and the turboshaft delivers shaft power through a free power turbine. Know single, twin and triple spool layouts and that the starter normally turns the high-pressure spool. At level 1 the questions are descriptive: which engine type, which spool, what bypass ratio means.

Under EASA rules, APUs and piston engines are also level 1. An APU is a small gas turbine that supplies electrical power and bleed air, controlled by its own electronic controller with an automatic start sequence and protective shutdowns for overspeed, low oil pressure, high EGT and fire. For piston engines, the four-stroke cycle, dual magnetos and the idea of carburettor versus injection metering are enough.

Electric and hybrid propulsion (EASA, level 2)

This is new content and is examined at the same depth as FADEC. The chain is battery, power electronics (inverter or motor controller), motor and propeller or fan. Know why permanent-magnet synchronous motors are used, what the inverter does (turns DC into variable-frequency AC to control speed and torque), what the battery management system monitors (cell voltage, temperature, state of charge and state of health) and the high-voltage safety steps: isolate, lock out, wait for capacitors to discharge, prove dead with rated equipment. Hybrid configurations are a favourite: in a series hybrid the combustion engine only drives a generator; in a parallel hybrid both the engine and the motor drive the propulsor.

FADEC (level 2 in both systems)

FADEC questions are the core of 14.1. A full authority digital engine control has two independent channels, one active and one in standby, which alternate between flights. It has full authority over fuel flow with no hydromechanical back-up, commands the fuel metering unit through a torque motor or servo valve and reads metering-valve position through resolvers or LVDTs. Once the engine is running, it is powered by its own permanent-magnet alternator on the accessory gearbox, with aircraft power for start and back-up.

Know the inputs (thrust lever angle, N1, N2, inlet and compressor temperatures and pressures, EGT, air data) and the functions: thrust management in N1 or EPR mode, automatic start with hot and hung start protection on the ground, overspeed and over-temperature limiting, variable stator vanes, bleed valves, active clearance control and thrust reverser control. The engine identification or rating plug is a reliable question: it tells the EEC the engine's thrust rating so the computer can be changed without re-programming.

Exam tip: If a question asks what happens when both FADEC channels fail, the answer is never "the hydromechanical back-up takes over". A full authority system has none; the engine goes to a defined fail-safe state.

Sub-module 14.2: engine indication

This is the most avionic part of the module, at level 2, and the largest share of marks.

Temperatures

EGT, ITT and TGT are measured by chromel-alumel thermocouples connected in parallel, so the gauge shows the average and one failed probe changes the reading little. A thermocouple's output depends on the difference between the hot and cold junctions, so the indicator needs cold-junction compensation, and the leads are of thermocouple material and calibrated resistance. Never repair them with copper wire or shorten them. Oil, fuel and coolant temperatures use resistance bulbs read by a Wheatstone bridge or ratiometer.

Speed, thrust and torque

Tacho-generators produce three-phase AC whose frequency, not voltage, drives the indicator, so a weak generator output still reads correctly. Magnetic pickups count passing gear teeth or fan blades. Thrust indication uses EPR, the ratio of turbine discharge total pressure to compressor inlet total pressure, or N1 on high-bypass engines. A worked example: inlet pressure 14.7 psi and turbine discharge 25.0 psi give an EPR of about 1.70. Turboprops and turboshafts indicate torque, by a hydromechanical torquemeter that balances helical gear thrust with oil pressure or by a phase-shift system measuring shaft twist.

Fuel, oil, vibration and manifold pressure

Know the vane-type volume flowmeter and the motor-driven mass flowmeter, which measures mass independent of fuel density. Oil indication combines a pressure transmitter with a separate low-pressure switch, so comparing the two separates an instrument fault from a real loss of pressure. Vibration uses piezoelectric accelerometers and tracking filters locked to N1 and N2. Manifold pressure on piston engines is absolute pressure, so it reads ambient with the engine stopped.

The engine indicating systems note has a troubleshooting table (for example, a low EPR with other parameters normal points to a leak in the exhaust pressure line), and the Pro drill for 14.2 gives you a focused set of questions.

Sub-module 14.3: propeller systems (EASA)

Only a couple of questions under EASA rules, but they are easy marks if you know four things: how propeller speed is sensed and displayed, electronic propeller control with an electrohydraulic servo valve and beta feedback, the difference between synchronising (same rpm) and synchrophasing (same rpm plus a set blade phase angle), and electrical de-icing, where power reaches the blades through slip rings and brushes and a timer cycles the heaters. Auto-feather on take-off engine failure also appears. For the mechanical side of propellers, B1 candidates sit Module 17; B2 candidates do not.

Sub-module 14.4 (UK 14.3): starting and ignition

Large turbine engines use an air turbine starter driven by APU, ground cart or cross-bleed air, with an electrically controlled start valve and a clutch that disengages after start. Smaller engines use a DC starter or a starter-generator. Know the automatic start sequence: start valve open, N2 rising, ignition on, fuel on, light-off, acceleration, starter cut-out, ignition off. Know the abnormal starts: a hot start (EGT over the limit), a hung start (light-off but no acceleration to idle) and no light-off, which needs a dry motoring run to clear fuel.

Turbine ignition uses high-energy capacitor-discharge exciters and igniter plugs, with ground start, relight and continuous ignition modes. The maintenance safety requirement is examined directly: switch off and wait the specified time for the exciter capacitors to discharge before disconnecting leads. For piston engines, a broken magneto P-lead means the magneto is live with the switch off, so every propeller is treated as live.

How Module 14 relates to Modules 13 and 15

Module 14 is short, but it leans on earlier modules. Sensor principles come from Module 3 and 4, displays and data buses from Module 5, and engine instruments overlap with the instruments part of Module 13. Sitting Module 14 soon after Module 13 makes sense, because the revision overlaps.

Compared with Module 15, the B1 gas turbine paper, Module 14 trades mechanical depth for electrical depth. A B1 candidate learns how compressor surge happens; a B2 candidate learns how the FADEC detects and protects against it. If you hold both B1 and B2 or plan to, expect some overlap but different emphasis.

Background reading: the FAA's Aviation Maintenance Technician Handbook – Powerplant covers engine instruments, ignition and starting systems well. It uses US terms and regulations, so use it for the technology only.

Practising Module 14

Part-66 Prep has 352 original Module 14 questions, spread over the sub-modules like the official guidance. Every paper is sized to your category and the rules you choose on the start screen, so a UK candidate gets 24 questions in 30 minutes and an EASA candidate 32 in 40.

• B2: Module 14 paper 1 and free quick practice
• B2L: Module 14 paper 1 for B2L
• Printable: the Module 14 question sheet, 50 questions with an answer key

Neither EASA nor the CAA publishes past papers, and we do not use recalled exam questions. Our papers are exam-style papers written to the current syllabus and paper sizes. If you are searching for a Module 14 PDF, the printable sheet is the honest version of that.

Your study plan

1. Decide whether you are sitting EASA or UK CAA rules, and cross out the sub-modules that are not in your syllabus.
2. Read the free Module 14 engines note for engine types, electric and hybrid propulsion and FADEC.
3. Read the indication note and make a one-page sheet of sensors: what each measures, how, and its classic fault.
4. Take the free B2 quick practice, then sit paper 1 under timed conditions.
5. Drill engine indication until you score above 85% on it, then sit further papers. Papers 2 to 10 and the topic drills are in Pro.
6. Book when you have scored 85% or more on three different papers. If Module 14 is one of your first modules, try the free B2 diagnostic to see where you stand across the licence.