A&P Powerplant Written Test: Why It Is the Hardest of the Three
Last updated October 4, 2026
The A&P Powerplant written test (FAA test code AMP) has 100 multiple-choice questions, a 2-hour time limit and a passing score of 70 percent (FAA Airman Knowledge Testing Matrix, revised 9/25/26, p. 6). It is the hardest of the three A&P tests by the numbers: in 2025 only 63.04% of the 17,572 Powerplant tests taken were passes (FAA 2025 Airman Knowledge Test statistics). This guide shows where the questions come from and what in the FAA’s standard makes this test demanding.
The AMP test at a glance
| Powerplant (AMP) | |
|---|---|
| Questions | 100 |
| Time allowed | 2 hours |
| Passing score | 70% (70 correct) |
| Minimum age to take the test | None (“N/A” in the matrix) |
| Figures | Testing supplement FAA-CT-8080-4G, Appendix 2 |
| Tests taken in 2025 | 17,572 |
| Pass rate in 2025 | 63.04% |
The 70 percent mark is also in regulation (14 CFR 65.17(b)). The test may include unscored validation questions that are not part of the 100, but the 2 hours includes the time spent on them (testing matrix, p. 2).
How Powerplant compares
| 2025 | Tests taken | Pass rate |
|---|---|---|
| General (AMG) | 22,585 | 69.59% |
| Airframe (AMA) | 16,885 | 74.01% |
| Powerplant (AMP) | 17,572 | 63.04% |
Source: FAA 2025 Airman Knowledge Test statistics. Of the high-volume FAA knowledge tests in 2025, Powerplant had the lowest pass rate.
The 13 subjects and their weights
The FAA blueprint gives each subject a range, as a share of the 100 questions (Companion Guide to the mechanic ACS, FAA-G-ACS-1, Change 2, ch. 3, p. 14). With 100 questions, each percent is one question.
| Subject | Share of questions | Handbook chapter |
|---|---|---|
| A. Reciprocating Engines | 5-15% | 1, 8 |
| B. Turbine Engines | 5-10% | 1, 8 |
| C. Engine Inspection | 5-10% | 10 |
| D. Engine Instrument Systems | 5-10% | 10 |
| E. Engine Fire Protection Systems | 5-10% | 9 |
| F. Engine Electrical Systems | 5-15% | 4 |
| G. Engine Lubrication Systems | 5-10% | 6 |
| H. Ignition and Starting Systems | 5-10% | 4, 5 |
| I. Engine Fuel and Fuel Metering Systems | 5-10% | 2 |
| J. Reciprocating Engine Induction and Cooling Systems | 5-10% | 3, 6 |
| K. Turbine Engine Air Systems | 5-10% | 3 |
| L. Engine Exhaust and Reverser Systems | 5-10% | 3 |
| M. Propellers | 5-10% | 7 |
Chapters refer to the Aviation Maintenance Technician Handbook - Powerplant, FAA-H-8083-32B (2023). The two heaviest subjects are Reciprocating Engines and Engine Electrical Systems, the only ones that can reach 15 questions each. Together they can be up to 30 of your 100 questions.
Why Powerplant trips people up: what the ACS asks for
The FAA does not publish reasons for pass rates. What it does publish is the standard the test is written from: Section III of the Aviation Mechanic Airman Certification Standards, FAA-S-ACS-1 (the ACS, dated November 1, 2021, pp. 44-59). Reading it closely shows five things that make this test ask a lot of you.
1. You have to know two different kinds of engine, all the way through. Reciprocating and turbine engines each get their own main subject (A and B) and their own air subject (J for induction and cooling, K for turbine air). Then several other subjects ask about both. Ignition covers the “Three electrical circuits of a magneto system” (AM.III.H.K4) and “Turbine engine ignition systems” (H.K9). Fuel metering runs from “Float carburetor theory” (I.K2) to “Components, theory, and operation of turbine engine fuel metering system” (I.K8). Exhaust covers both engine types (L.K1, L.K2), and Propellers includes “Turbine engine propeller reverse/beta range operation” (M.K5) (ACS, pp. 52-59).
2. It is a theory test. 22 of the 119 Powerplant knowledge elements use the word “theory” (for example “Reciprocating engine operating principles/theory of operation,” AM.III.A.K2, ACS p. 44). Memorizing part names is not enough; you need to know why a system behaves as it does.
3. Electrical knowledge carries over from General. Engine Electrical Systems can be up to 15% and its elements include generators, alternators, starter generators, voltage regulators, AC and DC generation, “The purpose and procedure for paralleling a dual-generator electrical system” (F.K8) and constant speed drive and integrated drive generator systems (F.K9) (ACS, p. 50). If your General electricity is shaky, it shows here.
4. The widest subject is capped at 10%. Engine Fuel and Fuel Metering Systems has 21 elements (16 knowledge and 5 risk management), more than any other Powerplant subject, from carburetors and continuous-flow fuel injection to hydromechanical fuel controls, nozzles, pumps, valves and filters (ACS, pp. 53-54). You cannot skip it, but it is at most 10 questions, so it rewards broad understanding over deep detail.
5. Modern digital systems appear in three places. The digital engine control module (FADEC) is an element in Engine Instrument Systems (D.K9), Ignition and Starting (H.K6) and Fuel Metering (I.K5). Instruments also include EICAS (D.K8) and ECAM (D.K10) (ACS, pp. 47-54).
The handbook points the same way. Its table of contents has troubleshooting sections in chapters 3, 5, 6, 7, 9, 10 and 11, and chapter 10 alone covers engine, turbine, turboprop, EGT and tachometer troubleshooting (AMT Powerplant handbook, contents, pp. iv-xx).
Knowledge and risk management elements
Each ACS subject lists knowledge elements (K: “The applicant demonstrates understanding of”) and risk management elements (R: “The applicant demonstrates the ability to identify, assess, and mitigate risks associated with”). Skill elements (S) belong to the practical test. Powerplant has 119 coded knowledge elements and 44 risk management elements.
Do not skip the R elements. The ACS says “Knowledge and risk management elements are also evaluated during the knowledge testing phase of the airman certification process” (ACS, Appendix 1, p. A-2). Powerplant R elements are often about running engines safely, such as “Working around reciprocating engines with an ungrounded magneto” (AM.III.H.R3, p. 52) and “Foreign object damage” (B.R4, p. 45).
Missed codes are printed on your test report, and “All deficient knowledge areas, as indicated by the ACS codes on the AKTRs, are retested during the oral portion of the test” (ACS, p. A-1).
The testing supplement: Appendix 2 is short
Appendix 2 of the Airman Knowledge Testing Supplement, FAA-CT-8080-4G (2018) has just seven Powerplant figures, on pages 2-1 to 2-7 (contents, p. vi). Each one lines up with an ACS element:
| Figure | Caption | Related ACS element |
|---|---|---|
| 1 | Airworthiness directive excerpt | III.C.K5, compliance with ADs |
| 2, 3 | Fire extinguisher pressure chart | III.E.K5, extinguishing system maintenance and inspection |
| 4 | Electric wire chart | III.F.K7, finding the correct wire size |
| 5 | Starter-generator circuit | III.F.K3, starter generators |
| 6 | Fuel/air ratio graphs | III.I.K1, fuel/air ratio and carburetor theory |
| 7 | Fuel system | III.I.K10, fuel system operation |
The General appendix also has two engine performance charts (Figures 38 and 41), and the ACS lists “Reciprocating engine performance (e.g., PLANK, SFC)” under Powerplant (AM.III.A.K7, p. 44).
On-screen images are now part of the mechanic tests. The February 2026 FAA bulletin said: “Effective April 2026, the following exams will feature questions with embedded images,” including “Aviation Maintenance Technician (General, Airframe, and Powerplant)” (ATCA, February 2026, p. 4). The September 2026 edition lists them among exams that already “feature questions with embedded images,” and says “the specific images used in active test questions cannot be previewed” (ATCA, September 2026 Special Edition, p. 5). As of October 2026, “Until the removal, candidates will continue to have access to the testing supplement for their exam” (p. 5). So learn to read any wire chart, circuit or fuel schematic, not only the seven in the book.
The same September edition says PSI is assessing the AMG, AMA and AMP tests and that “Modifications based on the assessments of the exams mentioned above are anticipated to be implemented in 2027” (p. 4).
Where Powerplant fits in your order
- Your authorization sets which tests you may take: a school document covers the curriculum you completed, and an FAA Form 8610-2 covers the boxes checked on it (Companion Guide, p. 12; testing matrix, p. 6).
- On an original application, the form that authorizes Powerplant also authorizes the General test (testing matrix, p. 6).
- All the prescribed tests must be passed within 24 months (14 CFR 65.71(a)(3)).
- Pass each written section before applying for the oral and practical tests (14 CFR 65.75(b)), except school students under 14 CFR 65.80.
Nothing in these rules says Powerplant must come last. Because subjects F and H lean on electricity, many of the elements will make more sense after General subject A. See the General guide and the Airframe guide.
A 4-week study plan
A suggested plan using the Powerplant handbook. It is not an FAA requirement.
- Week 1: the two engines. Chapter 1 (Aircraft Engines), both reciprocating and gas turbine, and chapter 8 (Engine Removal and Replacement). Draw the four-stroke cycle and a turbine’s airflow from memory before moving on.
- Week 2: fuel, air and oil. Chapter 2 (Engine Fuel and Fuel Metering), chapter 3 (Induction and Exhaust) and chapter 6 (Lubrication and Cooling).
- Week 3: electrical, ignition and fire. Chapter 4 (Engine Ignition and Electrical), chapter 5 (Engine Starting) and chapter 9 (Engine Fire Protection). Revisit General handbook chapter 12 for any electrical gaps.
- Week 4: propellers, instruments and inspection. Chapter 7 (Propellers) and chapter 10 (Engine Maintenance and Operation, including instruments and troubleshooting). Read the engine and nacelle group and propeller group in 14 CFR part 43, appendix D, paragraphs (d) and (h). Then take full 100-question tests at 2 hours and look up every miss by its ACS code.
Try one: magneto circuits
For discussion, a high-tension magneto system is divided into how many circuits, and what are they?
Answer: three circuits, the magnetic circuit, the primary electrical circuit and the secondary electrical circuit. The Powerplant handbook says the system “can be divided, for purposes of discussion, into three distinct circuits: magnetic, primary electrical, and secondary electrical circuits” (AMT Powerplant handbook, ch. 4, p. 4-2). This is ACS element AM.III.H.K4.
Test day
Get an FAA Tracking Number through IACRA, set up a PSI account, then book and pay (Companion Guide, ch. 4, p. 15). Check the current fee when you book. Bring photo ID and your original authorization (p. 16). For graph questions “you may request a printed copy that you can mark in computing your answer” (p. 17). If you fail, you can retest after 30 days, or sooner with a signed statement from an airman holding the certificate and rating you are seeking, confirming extra instruction in each subject failed (14 CFR 65.19).
Common questions
Is the Powerplant test the hardest A&P test?
By pass rate, yes. In 2025 it was 63.04%, against 69.59% for General and 74.01% for Airframe (FAA 2025 statistics).
Which Powerplant subjects carry the most weight?
Reciprocating Engines and Engine Electrical Systems, at 5-15% each. The other 11 subjects are 5-10% each (Companion Guide, p. 14).
How many questions do I need right to pass?
70 of 100 (testing matrix, p. 6; 14 CFR 65.17(b)).
Is the Powerplant test changing?
As of October 2026 it uses embedded images, and the FAA expects changes from PSI’s assessment in 2027 (ATCA, September 2026, pp. 4-5).