EASA Module 4 study plan

Sketch block diagrams for one open-loop and two closed-loop aircraft systems, labelling input, error detector, amplifier, actuator and feedback path

Define gain, feedback fraction, error signal, steady-state error and hunting in your own words without notes

Explain the function of each element in a position-control servo chain (command synchro, control transformer, amplifier, motor, feedback transmitter)

Solve 10 simple numeric problems on forward gain versus feedback fraction and state whether the loop is under-, over- or critically damped

Describe the construction and operating principle of synchros and resolvers and the meaning of synchrony and torque-synchro operation

Contrast AC and DC servomotors by listing three construction and three performance differences

Diagnose five written fault scenarios (e.g. loss of feedback, reversed feedback, amplifier saturation) and name the visible symptom in each

Explain how damping, lag and lead networks and rate feedback are used to restore stability in a servo loop

Draw the forward and reverse characteristics of a silicon diode and mark the knee voltage and the reverse breakdown region

Trace the current path through half-wave, full-wave centre-tap and bridge rectifiers and state the output ripple frequency for each

Compare the construction, biasing and switching behaviour of NPN and PNP bipolar transistors and of N-channel and P-channel FETs

State the function and typical application of a Zener diode, a varactor, a thyristor and a triac

Identify the pin functions and ideal properties of an operational amplifier and state why negative feedback is used

Calculate the gain of inverting and non-inverting op-amp configurations given resistor values, for eight worked examples

Explain the purpose of integrated circuits, the meaning of scale of integration and how logic gates are implemented in IC packages

Label the parts of a transistor amplifier stage and explain the role of each component in setting bias and coupling

List and describe the properties of common board substrates (paper phenolic, epoxy glass, polyimide) and the meaning of single-sided, double-sided and multilayer

Sequence the manufacturing steps of a plated-through-hole and an SMT board from artwork and copper lamination to etching and finishing

Explain the purpose of solder mask, legend, conformal coating and board-level screening and grounding in an aircraft installation

Describe the difference between through-hole and surface-mount components and give two advantages of each

Describe the main causes and visual signatures of cold, bridged, dry and excess-solder joints

Explain ESD, its sources and the precautions taken when handling and storing boards

Apply standard inspection and bench-test steps to locate an open track, a shorted track and a faulty component on a supplied board description

State the limits and precautions for reworking solder joints and for removing and refitting SMT components

Re-attempt every question missed in weeks 1 to 6 and record the underlying fact you had wrong

Complete 60 mixed questions across all three domains under timed conditions and score each domain separately

Write a one-page summary sheet for each domain listing the equations, component functions and manufacturing or fault terms most likely to be tested

Sit two full-length timed mock exams covering all three domains and finish each within the allotted time

Identify the three weakest topics from the mock scores and close each gap with a targeted revision session

Recite from memory the key servo terms, the rectifier and op-amp output relationships and the main PCB manufacturing and fault terms