Part-66 Module 7: Maintenance Practices

No part of this module is examined more deeply than the part of the job that happens before a spanner moves. Safety precautions for the aircraft and the workshop, workshop practices and tools all sit at level 3: isolating an electrical supply and knowing that it is isolated, working near fuel, oxygen and stored energy, jacking and trestling, the housekeeping that stops a dropped washer becoming loose article damage, and the correct use of a torque wrench, a micrometer and a dial test indicator, and EASA adds another level 3 row for the hazards of working on electrical systems and the protective equipment that goes with them. Level 3 asks you to put separate pieces of knowledge together and apply them, so what’s examinable isn’t the precaution but the reason behind it: the difference between knowing a supply must be isolated and knowing what you’d check before you believed it.

Most of the module is bench work, and the bench begins with a skill that uses no tools at all: reading the sheet in front of you, where engineering drawings, diagrams and standards means title blocks, revision letters and the schematic deliberately not to scale. Fits and clearances is what the drawing’s numbers mean: shaft and hole tolerances, interference against running fits, the micrometer and bore gauge that tell you which of the two has been specified, and the feeler gauge that measures the clearance once the parts are together. The electrical wiring interconnection system sits at level 3 and earns it, because chafing against a bracket, a bend radius pulled too tight, a loom clipped to something that moves and a bonding lead left off are the failures that end as smoke.

What the mechanical rows share is that each turns on one number nothing further down the line will catch for you. A rivet is set to an edge distance and a pitch, and the dimple that lets a countersunk head sit flush is what stops a thin skin cracking around it. A flareless fitting is torqued rather than pulled tight, because the seal is made by a ferrule biting the pipe, not by how hard you leaned on the spanner. A bearing goes back to a clearance you measured yourself, a transmission to a backlash the manual states, and a control cable is read off a tensiometer and then corrected for the temperature of the hangar, because a rig set on a cold morning isn’t the rig you have by the afternoon. Material handling splits the same discipline between metal and composite: bend allowance and springback on one side, tap testing, moisture in the core and crushed honeycomb on the other, and EASA adds a level 1 row on additive manufacturing that the UK text doesn’t carry.

The only sustained arithmetic in the module is the aircraft’s own weight, and it comes in two rows because working out a centre of gravity and putting an aeroplane on jacks and scales are different jobs: datum, arm and moment on the paper, then the empty weight you start from and the ballast you may end up fitting on the ramp. Aircraft handling and storage has the same character, work done to a whole aeroplane rather than to a part of one: towing, jacking, mooring, clearing ice off the aeroplane on the ground, and the inhibiting a stored engine needs. Then 7.18 breaks into its lettered parts: defect types and visual inspection at level 3, with the structural repair manual, the inspection methods that leave the part unharmed, disassembly and reassembly and troubleshooting behind them, and together they come closer than anything else in Appendix I to describing the job as it’s actually done.

Last comes the day that goes wrong. One row is what you inspect after a lightning strike or HIRF penetration: entry and exit burn marks, a shattered static wick, a bonding resistance that has drifted. Another is what you inspect after a heavy landing or flight through turbulence, where the manual walks you round the gear, the wing root and the frames. Maintenance procedures comes last of all in the UK text and second to last under EASA, which adds documentation and communication after it; either way, that’s where the work stops being something you did and becomes something you signed for.

80 multiple choice questions and 100 minutes, then the written element, which under EASA belongs to this module alone, while under the UK CAA it’s one of three. The multiple choice half is drawn from the whole of a table 29 rows long, one of which is reserved and asks for nothing, while the rest run from safety precautions and workshop practices through fits and clearances and weight and balance to defect inspection and paperwork.

At the 75% pass mark, the multiple choice part needs 60 correct answers and leaves you 20 to lose. Those rows have little to do with one another, and that changes how an allowance disappears: losses don’t scatter thinly across the paper, they arrive together. Misread a torque figure and you’ve lost a question and nothing else, but never sit down with engineering drawings and standards and whatever the paper took from that row goes in one block, while the rows on either side of it stay perfectly answerable.

The written element is marked against a model answer broken into a list of key points, and the pass is 75% of those key points, with no significant error against any one of them. That rewards covering the ground rather than writing well: a plain answer that names every step and every precaution in order passes, and a fluent paragraph that quietly leaves a step out doesn’t. The two parts also stand on their own, so if you fail only the multiple choice, or only the essays, you sit that part again rather than the whole module. The writing can’t take away a paper you’ve already passed.

Nearly every line of this table is the same line twice, which is what makes the exceptions easy to read past. They are 7.4, where each authority puts a different subject under the same number; 7.15, which EASA leaves reserved and asks nothing for, while the UK fills it with welding, brazing, soldering and bonding; and the tail, where EASA adds a row on additive manufacturing and a closing row on documentation and communication that the UK table never reaches. Read down the column for the licence you’re sitting, treat the other one as background, and the next section takes each difference in turn.

Start at topic 7.4, where the two texts put different subjects behind one number. That’s the sharpest thing this module does. EASA lists “Potential safety hazards when working with electrical systems and protective equipment” there and sets it at level 3, one of only six rows EASA sets that high, while the UK lists “Avionic general test equipment” at the same number and its own table places that a level lower. So the disagreement isn’t one subject at two depths but two subjects sharing a code, and revising the wrong one leaves you holding something the other authority doesn’t examine here at all.

The exam around that row doesn’t differ at all: 80 questions, 100 minutes and two essays on both sides. On a module that argues as often as this one does, the sitting itself is the one thing the two texts never argue about, and it’s what keeps Module 7 out of the four papers the authorities genuinely set apart. The syllabus is another matter, and here the difference runs deeper than most: EASA calls it Module 7, while the UK still calls it Module 7A, having kept the letter suffixes EASA dropped when it rewrote the annex, and a B1.1 candidate sits the 7A version.

Topic 7.15 catches you the opposite way round: EASA has reserved the code and asks nothing for it, while the UK splits the same number into soldering methods and into welding, brazing and bonding methods, and examines both. So a UK candidate meets a soldering iron and a torch here and an EASA candidate doesn’t. The traffic isn’t all one way, though, because EASA carries a level 1 row on additive manufacturing and a closing row on documentation and communication, and the UK table has neither, ending at maintenance procedures.

The essays are the same size on both sides but sit differently in the two licences: under EASA they now exist only here, because Regulation (EU) 2023/989 removed them from Modules 9 and 10. A UK candidate writes these two and then one more in Module 9A and one in Module 10. EASA also lets a long multiple choice paper be sat in two complementary parts, and this one is long enough to qualify, while the UK offers nothing like that and its essay answers are still written on paper.

The wider split between the two authorities is on the EASA versus UK CAA page: mutual recognition, which licence to go for, and what happened to the conversion route.

This page covers one of the 13 papers. The rest of the guide covers the route they sit inside: what the exam is, what else you must have done besides passing it, and how the two authorities differ.

Both authorities require the same thirteen subjects. Only the numbering and some of the titles differ, and the UK still uses the A suffix on four of them where EASA has dropped it. Each has a page of its own.