Digital Techniques / Electronic Instrument Systems EASA Part-66 — Module 5 Practice Questions

What Module 5 covers — in plain English

Module 5 of the EASA Part-66 syllabus covers the digital and avionics knowledge that underpins every modern glass-cockpit aircraft. It runs from the basics — binary, octal and hexadecimal conversion, logic gate behaviour, ADC and DAC operation — through computer architecture, microprocessors and memory devices, into the integrated systems an engineer actually services on the line: EFIS, ECAM, EICAS, FMS, IRS, GPS, TCAS and fly-by-wire. ARINC 429 and ARINC 629 data buses feature heavily, as do fibre optics, CRT/LED/LCD electronic displays, and the maintenance practices around electrostatic sensitive (ESDS) components, HIRF protection bonding limits, EMC/EMI mitigation and the airworthiness implications of unapproved software changes.

All five licence categories sit Module 5, but the papers differ sharply in length. Category A and B3 candidates sit a shorter paper — 20 questions in 25 minutes — covering the broad principles at knowledge level 1 for most sub-sections. B1 candidates sit 40 questions in 50 minutes, and B2 / B2L candidates the longest paper of any module: 72 questions in 90 minutes, reflecting the avionics emphasis of those licences. Almost every sub-section is knowledge level 2 for B1, B2 and B2L; only Fibre Optics (5.10) drops to level 1 for B1. B3 candidates stay at level 1 for most sub-sections but level 2 for Electronic Instrument Systems (5.1), ESDS handling (5.12) and typical electronic/digital aircraft systems (5.15).

The question bank reflects the practical bias of the exam. Expect a steady stream of "what does X display show?" items, base-conversion arithmetic, ARINC word-format and parity questions, logic-gate truth tables, and handling/procedure items around ESDS labels, wrist-strap resistance bands and HIRF bonding-resistance limits. Numeric distractors usually fall close together, so candidates who shortcut the binary-to-hex grouping, forget that hex F = decimal 15, or mix up the EADI and EHSI display contents lose easy marks. Knowing the named avionics systems by their acronyms — ACARS, ECAM, EFIS, EICAS, FMS, GPS, IRS, TCAS, FBW, IMA — is essential, because the exam routinely uses them without expansion, and the three-option format means a hesitant guess has only a one-in-three chance of being right on any given question. The full per-section knowledge-level breakdown and sub-topic list is available on our Module 5 syllabus page.

These samples are drawn from our live Module 5 question bank of 1 094 questions. The full timed practice quiz draws 40 questions per attempt (or 20 for Cat A), scored against the official EASA 75 % pass mark, with weak-area tracking across attempts.