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ASTM NCATT Aircraft Electronics Technician (AET)

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Key Facts: CAET Exam

100 questions

Exam Length

AEA CAET

90 minutes

Time Limit

AEA CAET

70%

Passing Score

AEA CAET

8 areas

Content Domains

AEA CAET outline

ASTM Level 1

ASTM Standard Level

AEA / ASTM

Every 3 years

Renewal Interval

AEA CAET

3 attempts

Included per Purchase

AEA CAET

The CAET is the AEA's entry-level avionics technician certification, which AEA maps to Level 1 of the ASTM aircraft electronics technician standard; it has no prerequisites. The exam is 100 multiple-choice questions in 90 minutes with a 70% pass mark; a purchase includes up to three attempts ($119 remote proctored, $109 with an in-person proctor), and the credential renews every three years. It tests eight areas: maintenance procedures and Part 43 regulatory requirements; basic DC/AC electrical theory, solid-state and digital fundamentals, and aircraft electrical systems; communication, navigation and surveillance systems (VHF comm, VOR/ILS, GPS, DME, transponders, Mode S, ADS-B 1090ES/978 UAT, TCAS, ELT); flight instrument and pitot-static systems (including the 24-month § 91.411/§ 91.413 tests); digital databus systems (ARINC 429, CAN, Ethernet-based buses, MIL-STD-1553); aircraft wiring, hardware and installation per AC 43.13-1B; tools, test equipment and measurement techniques; and safety, housekeeping and best practices. Legacy NCATT AET holders can take an AET-to-CAET upgrade exam, and in March 2026 the FAA accepted the CAET as formal training for repairman certificate eligibility.

Sample CAET Practice Questions

Try these sample questions to review concepts for the CAET exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A resistor carries 0.5 A when 12 V is applied across it. What is its resistance?

A.6 ohms

B.24 ohms

C.0.04 ohms

D.60 ohms

Explanation: By Ohm's law, R = V / I = 12 V / 0.5 A = 24 ohms. This is foundational DC theory tested under the basic electrical theory area.

2Three resistors of 10 ohms, 20 ohms, and 30 ohms are connected in series across a 12 V source. What is the total circuit current?

A.2.0 A

B.0.20 A

C.0.60 A

D.1.0 A

Explanation: Series resistances add: 10 + 20 + 30 = 60 ohms. Total current I = V / R = 12 / 60 = 0.20 A.

3Two 100 ohm resistors are connected in parallel. What is the equivalent resistance?

A.200 ohms

B.100 ohms

C.0.02 ohms

D.50 ohms

Explanation: For two equal parallel resistors, the equivalent equals one resistor divided by the number of resistors: 100 / 2 = 50 ohms.

4A 28 V DC bus supplies a load that draws 7 A. How much power does the load consume?

A.196 W

B.4 W

C.35 W

D.21 W

Explanation: Power P = V x I = 28 V x 7 A = 196 W. The power formula is essential for sizing avionics circuit protection.

5In a capacitor, the property that opposes a change in voltage and stores energy in an electric field is best described as:

A.Inductance

B.Reluctance

C.Capacitance

D.Conductance

Explanation: Capacitance is the ability of a component to store charge and energy in an electric field between plates, opposing changes in voltage; it is measured in farads.

6In an AC circuit, the total opposition to current flow that combines resistance and reactance is called:

A.Resistance

B.Admittance

C.Impedance

D.Permeability

Explanation: Impedance (Z) is the vector sum of resistance and reactance in an AC circuit, measured in ohms, and governs current in circuits containing inductors or capacitors.

7A semiconductor diode in a circuit is intended to allow current to flow in only one direction. When the diode is forward biased, the anode is at a potential that is:

A.More positive than the cathode

B.More negative than the cathode

C.Equal to the cathode

D.Floating relative to the cathode

Explanation: A diode conducts when forward biased, which means the anode is more positive than the cathode by at least the forward voltage drop (about 0.7 V for silicon).

8Which logic gate produces a HIGH output only when ALL of its inputs are HIGH?

A.OR gate

B.NAND gate

C.AND gate

D.XOR gate

Explanation: An AND gate outputs logic 1 only when every input is logic 1; any low input produces a low output. Digital logic fundamentals support troubleshooting databus and avionics circuits.

9A technician measures 0 V across a load that should be energized, and full source voltage across an in-line switch that is closed. The most likely fault is:

A.Open contacts inside the switch

B.A short to ground at the load

C.An over-rated circuit breaker

D.Excessive load current

Explanation: Full source voltage dropped across a supposedly closed switch indicates the circuit is open at the switch (open contacts); all the voltage drops across the open point and none reaches the load.

10The transformer in an avionics power supply has 200 primary turns and 50 secondary turns. If 120 V AC is applied to the primary, the ideal secondary voltage is:

A.480 V

B.120 V

C.60 V

D.30 V

Explanation: Secondary voltage = primary voltage x (secondary turns / primary turns) = 120 x (50/200) = 30 V. This is a step-down transformer.

About the CAET Exam

The Certified Aircraft Electronics Technician (CAET) is the Aircraft Electronics Association's entry-level avionics technician credential, which AEA maps to Level 1 of the ASTM aircraft electronics technician standard. The exam is 100 multiple-choice questions in 90 minutes with a 70% passing score, delivered remote proctored through the Unmanned Safety Institute (USI) or in person at an AEA-approved proctor site. It covers eight areas: maintenance procedures and regulatory requirements, basic electrical theory and systems, CNS systems, flight instrument and pitot-static systems, digital databus systems, aircraft wiring, hardware and installation, tools, test equipment and measurement techniques, and safety, housekeeping and best practices. It has no prerequisites and requires renewal every three years.

Exam sponsor: Aircraft Electronics Association (AEA). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Questions

100 questions

Time Limit

90 minutes

Passing Score

70%

Exam / Certification Fees

$119 remote proctored / $109 in-person (includes 3 attempts)

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

Not published

Maintenance Procedures & Regulatory Requirements

14 CFR Part 43 maintenance records and return to service, persons authorized under §§ 43.3 and 43.7, Part 65 repairman privileges, Airworthiness Directives (Part 39), STCs and Form 337 major alterations, TSO/PMA parts eligibility, ICAs, and systematic troubleshooting using approved or acceptable data

Not published

Basic Electrical Theory & Systems

Ohm's law and power, series/parallel DC circuits, AC theory and impedance, transformers, diodes and transistors, digital logic and the resistor color code, plus aircraft electrical systems: batteries, alternators and regulators, bus bars, and circuit protection

Not published

CNS — Communication, Navigation & Surveillance Systems

VHF comm (118.000-136.975 MHz, 25 and 8.33 kHz spacing), VOR/ILS and marker beacons, GPS/WAAS, DME, transponders (1030/1090 MHz), Mode S, ADS-B (1090ES and 978 UAT), TCAS, 406 MHz ELTs, and weather radar

Not published

Flight Instrument & Pitot-Static Systems

Pitot-static instruments, the 24-month § 91.411/§ 91.413 tests to Part 43 Appendices E and F, the 29.92 in Hg pressure-altitude datum, gyroscopic instruments, AHRS and magnetometers, air data computers, EFIS/PFD, and blocked-port fault effects

Not published

Digital Databus Systems

ARINC 429 (32-bit word, label, SDI, SSM, odd parity, 12.5/100 kbps), CAN bus with 120-ohm termination, Ethernet-based buses such as Garmin HSDB and ARINC 664/AFDX, and MIL-STD-1553 command/response architecture

Not published

Aircraft Wiring, Hardware & Installation

AC 43.13-1B and 43.13-2B practices: wire selection and ratings, stripping within Table 11-13 strand-damage limits, crimping and splicing, routing above fluid lines, clamping and bend radii, bonding and shielding, coax, and antenna installation

Not published

Tools, Test Equipment & Measurement Techniques

Multimeter voltage, current, and resistance techniques, megohmmeter insulation tests, calibrated crimp and torque tools, oscilloscopes and TDRs, pitot-static and transponder ramp test sets, and calibration control

Not published

Safety, Housekeeping & Best Practices

Battery and electrical safety, lockout/tagout, stored-energy hazards, RF radiation safety around weather radar (AC 20-68B), ESD protection, FOD control and tool accountability, soldering hygiene, and maintenance human factors

Preparing for the CAET Exam

What You Need to Know

Passing score: 70%
Exam length: 100 questions
Time limit: 90 minutes
Exam / certification fees: $119 remote proctored / $109 in-person (includes 3 attempts) Official sources

Using Our Practice Resources

Work through all 100 available questions
Review every answer and explanation
Track weak areas and revisit them
Use our AI tutor for tough concepts

CAET: Suggested Study Strategy

1Memorize the CNS frequency map: VHF comm 118.000-136.975 MHz, VOR/localizer 108-118 MHz, glideslope 329-335 MHz, transponder interrogate 1030 MHz / reply 1090 MHz, and DME 960-1215 MHz

2Know the ADS-B links: 1090ES (1090 MHz) is required in Class A airspace (18,000 ft MSL to FL600), UAT (978 MHz) may be used only below 18,000 ft MSL, and FIS-B weather comes only on 978 MHz

3Lock in the ARINC 429 word: 32 bits, an 8-bit label sent MSB-first, SDI, data, the Sign/Status Matrix, odd parity in bit 32, and 12.5 or 100 kbps on a single-source twisted pair

4Remember the test rules: § 91.411 static system and altimeter tests (for IFR in controlled airspace) and § 91.413 transponder tests are each due within the preceding 24 calendar months, and both are recorded under § 43.9

5Drill AC 43.13-1B wiring rules: stay within the Table 11-13 strand-damage limits, route bundles above fluid lines with 6 inches of separation where possible, clamp at no more than 24-inch intervals, and keep bends at 10 times the largest wire's diameter

6Practice voltage-drop troubleshooting: full source voltage across a closed switch means an open contact, current is measured with the meter in series, and breakers are sized to protect the wire

Frequently Asked Questions

What is the CAET certification?

The Certified Aircraft Electronics Technician (CAET) is the Aircraft Electronics Association's entry-level avionics technician credential, which AEA maps to Level 1 of the ASTM aircraft electronics technician standard. It validates foundational knowledge across eight areas, from electrical theory and CNS systems to wiring, regulations, test equipment, and safety. In a March 2026 letter, the FAA accepted the CAET as formal training that can support repairman certificate eligibility under 14 CFR 65.101(a)(5)(ii).

How is the CAET exam structured?

The CAET exam has 100 multiple-choice questions, a 90-minute time limit, and a 70% passing score. It is delivered remote proctored online through the Unmanned Safety Institute (USI), or in person at an AEA-approved proctor site, and a single purchase includes up to three attempts.

How much does the CAET cost and how many attempts do I get?

The CAET costs $119 with virtual proctoring and $109 with an in-person proctor, and up to three attempts are included. There is a 24-hour wait between the first and second attempts and a two-week wait between the second and third attempts.

Are there prerequisites for the CAET?

No. AEA says anyone can sit for the CAET; it is designed for entry-level avionics technicians coming from aviation high schools, technical schools, military avionics, repair stations, or self-study.

What topics does the CAET exam cover?

The exam covers AEA's eight areas: maintenance procedures and regulatory requirements; basic electrical theory and systems; CNS (communication, navigation and surveillance) systems; flight instrument and pitot-static systems; digital databus systems; aircraft wiring, hardware and installation; tools, test equipment and measurement techniques; and safety, housekeeping and best practices. AEA does not publish a percentage weighting for each area.

How is the CAET different from the older NCATT AET?

The NCATT AET is the legacy ASTM credential, whose written exams are administered by SpaceTEC Partners. The CAET is AEA's current credential built on the updated ASTM standard. Current or former AET holders can take AEA's AET-to-CAET upgrade exam ($59 at the standard rate, 80% to pass), which tests only CNS, flight instruments, digital databus, and aircraft wiring.

How long is the CAET valid?

The CAET must be renewed every three years. AEA's recertification policy requires 18 continuing education hours per three-year cycle, earned through AEA training, regional meetings, the convention, FAASTeam or OEM training, or A&P renewal activity. Passing the CAET online recertification exam or completing CAET-Advanced satisfies the full requirement.