AMC 20-22 EWIS training: what the AMC requires, clause by clause

What does AMC 20-22 actually say?

AMC 20-22, “Aeroplane Electrical Wiring Interconnection System Training Programme”, is a short document: eight numbered sections and three appendices in the EASA Easy Access Rules for AMC-20. Sections 1 to 7 set purpose, objective, applicability, references, definitions and background; section 8 carries the two operative obligations — initial training per target group and continuation training within two years; the appendices hold the syllabi and lesson plans that courses are actually built from. This guide walks the document in order, quoting the load-bearing sentences. EWIS is one of several duties on a Part-145 organisation; our guide to Part-145 training requirements lists every one by clause.

AMC 20-22 at a glance

Figure	What it is
8 sections, 3 appendices	The whole document: sections 1 to 7 set purpose, definitions and background, section 8 carries the obligations, Appendices A to C hold the syllabi and lesson plans
3 Parts served	Part-21, Part-145 and Part-M organisations all take their EWIS training obligations from this one AMC — section 2
8 target groups	Everyone who comes into contact with aeroplane EWIS as part of their job, sorted by the work performed rather than the job title
2 groups with a direct regulatory basis	Target Groups 1 and 2, the EWIS maintenance and inspection staff on the Appendix A syllabus; training Groups 3 to 8 is the organisation’s choice
2 years	The continuation window: section 8(b) puts follow-on training in a period not exceeding two years, against the same appendix as the initial course

Sections 1 and 2 — purpose and objective

Section 1 states the philosophy in one sentence: the AMC “promotes a philosophy of training for all personnel who come into contact with aeroplane EWIS as part of their job and tailors the training for each workgroup to their particular needs”. That is the origin of the eight target groups — one programme, tailored per workgroup, derived from what section 1 calls best practices developed through extensive research.

Section 2 names the regulations the AMC serves:

“This AMC has been published in order to provide the approved organisations with acceptable means of compliance to comply with their training obligations as required in paragraphs 21.A.145 and 21.A.245 of Part-21, 145.A.30 and 145.A.35 of Part-145 and M.A.706 of Part-M with respect to EWIS.” — AMC 20-22, section 2

Note the spread: production and design organisations under Part-21 and CAMOs under Part-M read the same document as a Part-145 hangar. Section 2 then gives the objective — a model for the development of the organisation’s own EWIS training programme — and draws the line that shapes the whole market: Target Groups 1 and 2, the staff directly involved in EWIS maintenance and inspection, get the Appendix A syllabus; Groups 3 to 8 have no direct regulatory requirement, and their Appendix B training is the organisation’s choice.

Sections 3 to 5 — applicability and references

Section 3 keeps the AMC honest about its own status: it “describes acceptable means, but not the only means, of compliance”, built on lessons learned by the ATSRAC harmonised working groups, regulators, manufacturers, airlines and repair stations — and it “can be applied to any aeroplane training programme”. Sections 4 and 5 list the related documents (the basic regulation, Part-21, Part-M and Part-145 regulations, CS-25 and EU-OPS) and the sibling reading: AMC 20-21 on enhancing EWIS maintenance programmes and AMC 20-23 on standard wiring practices documents. EWIS training is one leg of a three-part ageing-systems package, which is why its vocabulary keeps pointing at maintenance data and wiring practices manuals.

Section 6 — definitions worth knowing

The definitions section is where the failure physics lives. Arc tracking is defined as:

“A phenomenon in which a conductive carbon path is formed across an insulating surface. This carbon path provides a short circuit path through which current can flow. Normally, a result of electrical arcing.” — AMC 20-22, section 6

Combustible, for this AMC, means material that keeps a fire going after the ignition source is removed. Those two definitions explain the syllabus’s fixation on contamination and cleaning: contaminated wiring supplies both the ignition path and the fuel.

Section 7 — why the AMC exists

The background section is blunt about the record:

“Regulators and Accident Investigators have conducted aircraft inspections and found wiring contaminated with items such as dust, dirt, metal shavings, lavatory waste water, coffee, soft drinks, and napkins.” — AMC 20-22, section 7

It adds the second finding — wiring harmed by collateral damage while maintenance is performed on other systems — and notes that accident investigators specifically cited the need for improved training. Section 7 also bounds the document: it addresses only the training programme, not fleet wiring condition.

Section 8 — the two obligations

Everything operative is here, in two paragraphs. Initial training, per section 8(a), is conducted for each designated work group against the Appendix A or B programme, with curriculum and lesson plans in Appendix C — and the AMC is permissive about the classroom:

“The most important criteria are to meet the objectives of the Lesson Plans – Appendix C (using classroom discussion, computer-based training or hands-on practical training). Assessment or achieving the objectives should be at the discretion of the training organisation (such as written test, oral test or demonstration of skills).” — AMC 20-22, section 8(a)

Continuation training, per section 8(b), runs on the interval every EWIS certificate tracks:

“Refresher training should be conducted in a period not exceeding two years. It could consist of a review of previously covered material plus any new material or revisions to publications. Refresher training will follow the EWIS Minimum Initial Training Programme - Appendix A or B for that particular target group.” — AMC 20-22, section 8(b)

Same appendix as the initial course, rolling two-year window — how that window is tracked alongside the human factors and fuel tank safety cycles is covered in the two-year continuation guide.

Appendices A and B — the syllabi

Appendix A is the minimum initial programme for Target Groups 1 and 2: numbered subjects in lettered sections — general EWIS practices, wiring practices documentation, inspection, housekeeping, wire, connective devices and connective device repair — each introduced with a “know or demonstrate” objective and marked with an X per group. Group 1, the maintainers, take the tooling, troubleshooting, measurement and the whole connective-device-repair section; Group 2, the inspectors, take human factors in inspection and the zonal inspection subjects instead. Appendix B reuses the same subject numbering across columns for Groups 3 to 8, thinning to safety practices, contamination and “low level” damage awareness for service staff and crew. The full group-by-group breakdown is in EWIS target groups 1 to 8 explained, and the decision of which groups your organisation must train at all is in who needs EWIS training.

Appendix C — the lesson plans

Each module in Appendix C carries three parts: an overview, the objectives, and strategies for delivery. The objectives are the compliance floor — section 8(a) makes meeting them “the most important criteria” — while the strategies reveal the intended classroom, down to Module G’s:

“This class is primarily a hands-on class to give the student motor skills in the repair of connective devices from their aeroplane.” — AMC 20-22, Appendix C, Module G, Strategies

That sentence is why a Target Group 1 programme cannot finish entirely on a screen, and it anchors our analysis of when online EWIS training is accepted.

How a Part-145 organisation plugs into it

For a maintenance organisation the route in is AMC5 145.A.30(e), “Other trainings”, which asks the organisation to assess the need for particular trainings, names EWIS as its first example, and points at AMC 20-22 for the programme. Assess the need, map staff to target groups, train against the right appendix, repeat within two years, and record the group and appendix on every certificate — the record mechanics live under 145.A.55.

Related courses. MOST.AERO does not yet run an EWIS course: EWIS Target Group 1 & 2 – Initial and EWIS Target Group 1 & 2 – Continuation are coming soon. Meanwhile Part-145 Safety Training including Human Factors — Initial covers the separate 145.A.30(e) safety training the same staff carry, and the continuation due-date tool tracks the two-year window.