The FAA Aviation Mechanic certificate tests far more than component names: it asks you to classify work under 14 CFR Part 43, choose the right paperwork, and apply the correct engine or system procedure. This guide builds preparation around those decisions, with worked scenarios, a classification table, and a rubric you can score yourself against.
How the General, Airframe, and Powerplant requirements split the work
The FAA issues one mechanic certificate with an Airframe rating, a Powerplant rating, or both. Three knowledge tests cover the General, Airframe, and Powerplant subject areas; oral and practical tests follow, administered by a Designated Mechanic Examiner.
Start by seeing General as the shared foundation rather than a separate hurdle. The AMT-General Handbook covers mathematics, aircraft drawings, weight and balance, materials and processes, physics, electricity, inspection fundamentals, ground operations, and — critically — regulations, maintenance forms, records, and human factors. The regulatory and documentation content in General is what powers the classification decisions you will practice throughout this guide, so treat those chapters as tools, not trivia.
The Airframe and Powerplant handbooks then build rating-specific knowledge on that base, and the knowledge tests must be passed before the oral and practical (O&P) tests. A Designated Mechanic Examiner administers the O&P using the applicable mechanic testing standards, where you demonstrate skill tasks and answer oral questions. Administrative specifics — eligibility paths, documentation, and procedures — live on the FAA's Become an Aviation Mechanic page and in 14 CFR part 65, subpart D, so confirm current details there rather than relying on secondhand summaries.
Four Part 43 terms that change your paperwork: maintenance, preventive maintenance, major repair, major alteration
Part 43 separates maintenance, preventive maintenance, rebuilding, and alteration, and divides repairs and alterations into major and minor. Each classification determines who may perform the work and which forms and record entries legally close it out.
Learn the definitions as a decision ladder. Maintenance means preserving an article so it returns to its original or properly altered condition. Preventive maintenance is the narrow list of simple operations in Part 43 Appendix A that certain non-mechanic personnel may perform on aircraft they operate. A major repair or major alteration is one that, if improperly done, might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness — and Appendix A lists specific examples. Everything else is minor.
Each rung of the ladder ends in different paperwork. A record entry under 43.9 closes routine maintenance; inspection entries follow 43.11. Major repairs and major alterations are documented on FAA Form 337 and recorded per Part 43 Appendix B. The performance rules in 43.13 require methods, techniques, practices, tools, and materials acceptable to the Administrator — typically the manufacturer's maintenance manual or other approved data. When you study any procedure, finish the thought by naming its closing document; that habit converts isolated facts into usable judgment.
Scenario drill: classifying a wing skin repair before you sign the record
A torn wing skin near a main spar looks like routine sheet-metal work. Testing the classification against Part 43 Appendix A and the structural repair manual changes the form, the record entry, and the approval decision.
The situation: a torn lower wing skin panel overlapping a main spar carry-through structure. The plausible mistake is treating it as a minor repair — removing rivets, installing a patch, making a 43.9 entry, and approving the aircraft for return to service. What went wrong: the classification was never checked. A repair to a primary structural member, or one that if improperly done could appreciably affect structural strength or flight characteristics, points toward major under Appendix A and the Part 43 definition. The mechanic guessed instead of deciding.
The better decision: consult the manufacturer's Structural Repair Manual first. If the SRM provides an approved, limits-bounded repair within its classification, follow it exactly. If the work meets the major criteria, complete FAA Form 337 describing the repair and referencing the approved data used, record it per Part 43 Appendix B, and only then approve for return to service within your mechanic privileges. Why it matters: the classification decision — not the quality of the rivet work — determines whether the aircraft is legally airworthy, and the record is what proves it.
Airframe systems: tracing the chain instead of naming the part
Airframe study pays off when you can trace a system from input to output. Structures, hydraulic and landing gear systems, ice and rain control, and fire protection are useful as working chains, not as isolated component names.
On structures, separate two vocabularies. First, the stress vocabulary — tension, compression, shear, bending, and torsion — explains why repairs must restore both original contour and original strength, and why factors like rivet spacing and edge distance are specified rather than optional. Second, the material vocabulary distinguishes sheet-metal assembly and repair from composite, fabric, and wood structures, each with its own inspection signs and repair logic. Studying repairs through load paths makes the airframe handbook's rules feel derived instead of arbitrary.
For transport systems — hydraulics, landing gear, fire detection and extinguishing, oxygen, ice and rain — draw a one-line functional chain for each system and ask what happens downstream when one element fails. A hydraulic system becomes pressure generation, storage, delivery, actuation, and return; a failure at any link produces a specific symptom. This mirrors how scenario-style questions ask you to reason from a symptom to a cause, and it gives you a reusable diagram habit for the oral test, where explaining a system out loud is the actual task.
Powerplant decisions: reciprocating and turbine engines answer the same question differently
Powerplant study contains two engine logic sets: reciprocating engines with spark ignition and discrete cycles, and gas turbines with continuous combustion. Applying one engine's logic to the other's start, metering, or inspection scenario creates avoidable errors.
For reciprocating engines, master the named contrasts. Detonation is uncontrolled combustion after normal ignition; preignition is ignition that begins early from a hot spot inside the cylinder. Fuel metering splits into carburetor systems, with their icing behavior, and fuel injection, which eliminates carburetor icing but adds its own distribution concerns. Ignition timing, valve timing, and the four-stroke cycle then determine when each event must happen. These are exactly the pairs worth writing on one comparison page, because each pair has a distinct symptom and a distinct remedy.
Paper scenario: during a turbine engine start, exhaust gas temperature climbs rapidly toward its limit while RPM stays below stable idle. The plausible mistake is dismissing the rise as a cold-morning gauge quirk and continuing fuel flow. The better decision: recognize a hot start, terminate it using the manufacturer's procedure — cutting fuel and motoring as the manual directs — then troubleshoot before another attempt, because continued fuel into an overtemperature engine can damage hot-section components. Get the start-fault vocabulary straight as the handbooks present it: a hot start is overtemperature; a false or hung start lights but fails to accelerate properly to idle; and a complete failure to light is the separate engine-fails-to-start condition rather than a synonym for either.
Major or minor? A classification decision table you can drill against
Use one ordered table for any repair-or-alteration classification decision: check Appendix A, test the appreciable-effect definition, ask whether type design changes, and end at the closing paperwork. Practicing the order makes the decision fast and defensible.
Apply the rows in sequence and stop at the first decisive answer. Start with Part 43 Appendix A because it lists concrete examples — repairs to skin, webs, and members of primary structure among them — so a listed item settles the major question immediately. If nothing is listed, move to the appreciable-effect test from the regulation's language, then to whether the work alters the type design or merely restores original condition. The final row is the paperwork consequence, which is the natural follow-up once a classification is named.
Treat the table as a study aid, not a substitute for the rule or the manufacturer's data. Classification is fact-specific: the same physical operation can be minor on one aircraft and major on another depending on structure and location, and an approved manual repair within stated limits governs how you perform it. When in doubt, the defensible answer cites the specific test you applied — the definition, the Appendix A example, or the approved data reference — rather than intuition or habit.
| Decision question | Points toward major | Points toward minor |
|---|---|---|
| Is the work listed in 14 CFR Part 43 Appendix A? | Yes — for example, repairs involving skin, webs, or members of primary structure | No listing, and no appreciable effect identified on review |
| Could improper work appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness? | Yes — the regulation's own test for major | No — the work is cosmetic or localized with no such effect |
| Does the work change the type design, or restore the original condition? | A design change is a major alteration requiring approved data | Restoring original condition without design change |
| What closes the job? | FAA Form 337 plus a record entry per Part 43 Appendix B | A record entry under 14 CFR 43.9, or 43.11 if it is an inspection |
A four-phase preparation sequence with a self-check rubric
Sequence study in four phases: map subject areas to handbook chapters, convert each chapter into a decision drill, rehearse oral answers aloud with tools and references, then run mixed timed review. Score every phase against the rubric, not a gut feeling.
Phase 1: list the subject areas in the mechanic certification standards and map each to chapters of the AMT-General, Airframe, and Powerplant Handbooks, so nothing in the standards lacks a home. Phase 2: for each area, write one scenario and its decision — a classification, a form choice, a procedure — and answer it in writing. Phase 3: rehearse the O&P format by explaining a task aloud, then performing or simulating it with the correct references at hand. Phase 4: run mixed, timed decisions across all three subject areas so you practice switching between regulation, airframe, and powerplant reasoning.
Practical exercise — the classification drill. Write six tasks: replacing a cabin door hinge; patching a spar web; replacing a main tire; adjusting engine valve clearance; installing a new antenna requiring a fuselage skin cut; weighing an aircraft and computing a new weight and balance. For each, classify the work and name the closing paperwork. Expected observations: the spar web repair and the skin-cutting antenna installation come out major, closing with Form 337 and an Appendix B entry; the hinge, tire, and valve tasks close with a 43.9 entry; the tire task also rewards checking directly against the Appendix A preventive maintenance list, since that list is short and precise; and the weighing with weight-and-balance computation is maintenance closed by a 43.9 record entry — weighing is not on the Appendix A preventive list. Rubric: a strong result justifies every classification by quoting the test applied, never by feel. Six justified answers means move to the next phase; four or five means reread Appendix A; three or fewer means redo the Phase 1 mapping for the regulations chapters. Treat these scores as learning milestones, not predictions of any test result.
- You can state the four Part 43 work categories and the major-repair definition from memory, word for word in substance.
- You can list the content of a 43.9 record entry: description of work, date, name, certificate number, signature, and certificate type held.
- You can draw a hydraulic or fuel system chain and explain the downstream effect of any one element failing.
- You can distinguish detonation from preignition, and hot start from false or hung start, and identify a complete failure to light as its own starting-fault condition.
- You can explain, in one minute, which Part 43 documents close a major repair versus a minor repair, and why.
References and further reading
Use these references to explore the concepts and check the latest information from the relevant organizations.