Search "AMG AMP AMA difference" and you'll find a lot of vague answers built around the word "license," which isn't quite how the FAA structures this. There's no such thing as an AMG license, an AMP license, or an AMA license on its own. There's a mechanic certificate, issued under 14 CFR Part 65, Subpart D, with two possible ratings attached to it: Airframe and Powerplant. AMG, AMA, and AMP are the three knowledge tests that feed into that certificate, and understanding what each one actually gates is the difference between planning your testing sequence correctly and wasting a testing-center fee on a test you weren't eligible to take yet.
The three tests, side by side
All three are administered under the same FAA testing supplement (FAA-CT-8080-4G) and the same companion guide (FAA-G-ACS-1). All three carry a 2.0-hour time allotment and a 70 percent passing score under 14 CFR § 65.17. The difference is question count and subject depth.
| Test | Full Name | Questions | Time | Passing Score | ACS Knowledge Areas |
|---|---|---|---|---|---|
| AMG | Aviation Mechanic General | 60 | 2.0 hrs | 70% | 12 |
| AMA | Aviation Mechanic Airframe | 100 | 2.0 hrs | 70% | 15 |
| AMP | Aviation Mechanic Powerplant | 100 | 2.0 hrs | 70% | 13 |
What each test actually covers
AMG's 12 knowledge areas are foundational and apply regardless of which rating you're chasing: Fundamentals of Electricity and Electronics, Ground Operations and Servicing, Aircraft Drawings, Weight and Balance, Fluid Lines and Fittings, Aircraft Materials/Hardware/Processes, Cleaning and Corrosion Control, Mathematics, Regulations/Maintenance Forms/Records/Publications, Physics for Aviation, Inspection Concepts and Techniques, and Human Factors.
AMA's 15 knowledge areas are structure- and systems-focused: Metallic Structures, Non-Metallic Structures, Flight Controls, Airframe Inspection, Landing Gear Systems, Hydraulic and Pneumatic Systems, Environmental Systems, Aircraft Instrument Systems, Communication/Light Signals/Runway Lighting Systems, Aircraft Fuel Systems, Aircraft Electrical Systems, Ice and Rain Control Systems, Airframe Fire Protection Systems, Rotorcraft Fundamentals, and Water and Waste Systems.
AMP's 13 knowledge areas center on engines and propulsion: Reciprocating Engines, Turbine Engines, Engine Inspection, Engine Instrument Systems, Engine Fire Protection Systems, Engine Electrical Systems, Engine Lubrication Systems, Ignition and Starting Systems, Engine Fuel and Fuel Metering Systems, Reciprocating Engine Induction and Cooling Systems, Turbine Engine Air Systems, Engine Exhaust and Reverser Systems, and Propellers.
Which tests you need depends on which certificate you want
This is the part that actually matters for planning. 14 CFR § 65.73 recognizes exactly two mechanic ratings: Airframe and Powerplant. There's no separate "General" certificate or rating. What General does, under § 65.75, is satisfy a knowledge-test requirement that applies to every applicant, regardless of which rating(s) they're pursuing. The FAA's own Companion Guide spells out the three valid combinations directly, describing an AMTS graduation document as authorizing an applicant to test on "either general and airframe; general and powerplant; or general, airframe, and powerplant."
In plain terms: if you want the Airframe rating only, you take AMG and AMA. If you want the Powerplant rating only, you take AMG and AMP. If you want the combined Aviation Mechanic certificate with both ratings, commonly referred to as an A&P certificate, you take all three: AMG, AMA, and AMP. There is no path to an Airframe or Powerplant rating that skips the General test.
Order matters, and it's not optional
The FAA is explicit that General has to come first. Per FAA guidance on mechanic testing: "You must take the General knowledge test first, followed by the Airframe and/or Powerplant knowledge test(s)." The one carve-out is for AMTS (Aviation Maintenance Technician School) students. Under 14 CFR § 65.75(c), a student can take the AMG test before completing their full experience requirement under § 65.77, provided the school issues an authenticated document confirming they've finished the General portion of the curriculum. That's an exception to the experience timeline, not an exception to the testing order, AMG still comes before AMA or AMP.
The experience requirement behind all three
Before sitting for any of these knowledge tests, applicants have to satisfy 14 CFR § 65.77. That means either an authenticated completion document from an FAA-certificated AMTS, or documented practical experience: at least 18 months working with the procedures, tools, and equipment used in constructing, maintaining, or altering airframes or powerplants for a single rating, or at least 30 months of concurrent experience across both if you're going for the full A&P certificate. Once you've passed the written tests, you have 24 calendar months (per § 65.71(a)(3)) to complete the oral and practical portions of testing before your Airman Knowledge Test Report expires and you'd need to retest.
What passing all three actually unlocks: Inspection Authorization
There's a fourth test in this family worth knowing about, even though it's not one of the three certification tests: Inspection Authorization (IAR). It's not a path to a rating, it's an add-on privilege for mechanics who already hold both ratings. Per 14 CFR § 65.91, eligibility requires holding a currently effective mechanic certificate with both an Airframe and a Powerplant rating, each in effect for at least three years, plus at least two years of active engagement maintaining certificated aircraft. The IAR knowledge test itself is 50 questions, with 3.0 hours allotted and the same 70 percent passing score, and it's only available at testing centers specifically authorized to administer it. IA holders gain the privilege of approving major repairs and alterations for return to service and performing annual and progressive inspections, authority a standard A&P certificate doesn't carry on its own. It's a useful marker of where the AMG/AMA/AMP path eventually leads for mechanics who stay in the field long enough to qualify.
The experience math changes depending on your target
The 18-month versus 30-month experience split under 14 CFR § 65.77 is easy to misread. It's not 18 months per rating, stacked, it's 18 months total if you're pursuing one rating, or 30 months total if you're concurrently building experience toward both. That 30-month figure isn't simply double 18, it reflects concurrent experience across both airframe and powerplant work rather than two separate 18-month blocks completed back to back. Applicants going the Aviation Maintenance Technician School (AMTS) route bypass this practical-experience clock entirely, an authenticated completion document from an FAA-certificated Part 147 school satisfies § 65.77 on its own, which is a major reason structured AMTS programs remain the faster route to test eligibility compared to on-the-job apprenticeship hours.
Retesting works the same way across all three
Fail any of the three, AMG, AMA, or AMP, and the retest rules under 14 CFR § 65.19 apply identically. The default is a 30-day waiting period before you can sit for the same test again. That wait is waived if you present a signed statement from an airman who already holds the certificate and rating you're seeking, certifying that they've given you additional instruction covering the subjects you missed and consider you ready to retest. Either way, you have to submit your failed Airman Knowledge Test Report at the retest, and once you do pass, that AKTR is valid for 24 calendar months before it expires and the written portion has to be repeated. None of the three tests gets special retest treatment, the process is identical whether you're retaking a 60-question General test or a 100-question Airframe or Powerplant test.
Why the question counts differ the way they do
It's tempting to assume AMA and AMP simply have more questions because they're "harder," but the more accurate read is that they cover more distinct systems. AMG's 12 knowledge areas are largely cross-cutting fundamentals, math, materials, regulations, inspection concepts, that apply no matter which aircraft system you eventually specialize in. AMA's 15 areas and AMP's 13 areas are each built around discrete, named aircraft systems: landing gear, hydraulic and pneumatic systems, ice and rain control, on the airframe side; reciprocating engines, turbine engines, ignition and starting systems, on the powerplant side. More discrete systems means more subject areas need representation in the question pool to keep each one within its published percentage range, which is the direct mechanical reason the FAA sized AMA and AMP at 100 questions against AMG's 60.
What's actually available to practice on CQU right now
CQU currently runs two live practice exams in this space: a 240-question AMG bank and a 300-question AMP bank, both built around the full set of official ACS knowledge areas for their respective tests. There is no AMA (Airframe) practice exam on CQU at this time. If your certification path runs through Airframe, either alone or as part of a full A&P, that's a gap worth knowing about up front rather than discovering after you've built a study plan around it.
The short version
AMG is the gate everyone passes through, 60 questions covering foundational subjects that apply no matter which rating you're after. AMA and AMP are the two rating-specific tests, 100 questions each, and which one (or both) you take determines whether you walk away with an Airframe rating, a Powerplant rating, or the combined A&P certificate. None of the three tests are optional substitutes for each other, and the FAA's own documentation, from the CFR text to the Airman Knowledge Testing Matrix to the ACS Companion Guide, is consistent on the structure: General first, then Airframe and/or Powerplant, based on what certificate you're actually trying to earn. Plan your testing order around that structure rather than around whichever test happens to have prep material available, and the rest of the certification timeline tends to fall into place.