M vs E vs S: Which AME Licence Is Right for You?

Understanding the Three AME Licence Categories

Before diving into the comparison, it is important to understand the foundational structure. Transport Canada defines three distinct AME licence categories under the Canadian Aviation Regulations (CAR 573). Each licence authorizes you to certify maintenance in a specific domain of aircraft engineering. While the well-known M1 and M2 ratings relate to the scope of aircraft you can work on within Licence M, the broader M, E, and S categories represent entirely different disciplines.

If you have not yet read our complete guide to getting your AME license in Canada, start there for the overall process and eligibility requirements. This guide assumes you understand the basics and focuses specifically on helping you choose between M, E, and S.

Licence M — Airframe and Powerplant

Licence M is the most common AME category in Canada. It covers the mechanical, structural, and powerplant systems of an aircraft — essentially the "airframe" (fuselage, wings, landing gear, flight controls, hydraulics) and the "powerplant" (engines, propellers, fuel systems, lubrication). Licence M is further divided into the M1 and M2 ratings based on aircraft weight, which we cover in detail in our M1 vs M2 AME rating guide.

Scope: Licence M engineers perform inspections, repairs, modifications, and certifications on airframes and engines. This includes sheet metal repair, composite repair, engine removal and installation, landing gear overhaul, flight control rigging, hydraulic system troubleshooting, and corrosion prevention. If it involves structure, mechanics, or propulsion, it falls under Licence M.

Exams and syllabus: Licence M candidates must pass five core written exams under the TP14038E syllabus: CARS, Standards, Airframe, Powerplant, and Electrical. The Sky Licence question bank for Licence M contains over 1,200 questions across 24 chapters covering the complete syllabus. With 24 chapters of material — the most of any licence category — Licence M requires the broadest study effort.

Difficulty: Licence M is considered moderately difficult overall. The breadth of topics is wide, but the depth required in any single area is generally manageable. The Airframe and Powerplant exams are the most challenging, requiring strong understanding of both structural principles and engine thermodynamics. Many candidates report that the Powerplant exam is the toughest of the five M-licence exams.

Career paths: Licence M engineers work at airlines (Air Canada, WestJet, Porter), MROs (StandardAero, L3Harris, Avmax), flight schools, charter operators, corporate flight departments, and the Canadian Armed Forces. M1 engineers typically work in general aviation on Cessnas, Pipers, and Diamond aircraft. M2 engineers work on large turbine aircraft like Boeing 737s, Airbus A320s, and Bombardier regional jets.

Salary expectations: Licence M salaries range widely by rating and experience. Entry-level M1 engineers earn $45,000–$55,000 CAD. Experienced M1 engineers earn $60,000–$80,000. M2 engineers at major airlines start around $60,000–$70,000 and can reach $90,000–$110,000+ with seniority and lead roles. Shift premiums and overtime can add 15–25% to base salary.

Industry demand: Licence M has the highest demand of all three categories. The majority of aircraft maintenance tasks involve mechanical and structural work. With an aging workforce and Canada's growing aviation sector, Transport Canada projects sustained demand for Licence M engineers for at least the next decade.

Licence E — Electronics (Avionics)

Licence E covers the electronics and avionics systems of an aircraft. This includes communication and navigation radios, radar systems, autopilots, flight management systems (FMS), instrument landing systems (ILS), transponders, flight data recorders, cockpit voice recorders, and integrated modular avionics. Licence E engineers are the specialists who keep an aircraft's electronic nervous system functioning.

Scope: Licence E engineers diagnose and repair avionics systems, install new equipment (e.g., ADS-B Out upgrades, satellite communication systems), perform functional tests on navigation and communication systems, troubleshoot wiring and bus systems, and certify avionics modifications. The work is highly technical and requires strong understanding of electrical theory, digital systems, and radio frequency principles.

Exams and syllabus: Licence E candidates must pass the CARS exam, Standards exam, and specialized Electronics exams covering communication systems, navigation systems, pulse radars, auto-flight systems, instruments, and electrical power systems. The Sky Licence question bank for Licence E contains over 600 questions across 10 chapters. The 10-chapter syllabus is significantly narrower than Licence M, but the questions demand deeper technical precision.

Difficulty: Many candidates find Licence E exams more technically challenging than Licence M on a per-question basis. The subject matter — digital signal processing, RF engineering, pulse radar theory, integrated avionics architectures — requires abstract thinking and mathematical comfort. However, the narrower syllabus means you study fewer topics in greater depth. Candidates with an electronics or electrical engineering background often find Licence E easier than Licence M.

Career paths: Licence E engineers are in high demand at avionics shops, MROs with avionics divisions, airline technical operations, corporate flight departments with advanced avionics suites, and OEM service centres (Honeywell, Collins Aerospace, Garmin, L3Harris). As aircraft become more computerized — with fly-by-wire, glass cockpits, and connected aircraft systems — the demand for skilled avionics engineers continues to grow.

Salary expectations: Licence E engineers typically earn salaries comparable to or slightly higher than Licence M. Entry-level positions start around $50,000–$65,000. Experienced Licence E avionics specialists earn $75,000–$95,000, and senior avionics engineers at major airlines or OEMs can earn $100,000–$120,000+. Avionics specialists with expertise in emerging technologies (e.g., SATCOM,下一代 air traffic management systems) command premium rates.

Industry demand: Demand for Licence E engineers is growing faster than any other AME category. Modern aircraft contain exponentially more electronics than their predecessors. The Boeing 787 and Airbus A350, for example, have millions of lines of code and dozens of networked avionics systems. As the industry moves toward more electric aircraft and advanced automation, Licence E specialists will become increasingly critical.

Licence S — Structures

Licence S is the most specialized and least common of the three AME categories. It covers advanced structural repair and modification of aircraft airframes. Licence S engineers focus exclusively on the airframe structure — skin panels, stringers, frames, spars, bulkheads, control surfaces, and engine nacelles — using sheet metal, composites, and bonded repair techniques.

Scope: Licence S engineers perform major structural repairs, skin panel replacements, crack stop drilling, composite patch repairs, bonded doublers, and structural modifications under Supplemental Type Certificates (STCs). They work with engineering dispositions from the Aircraft Maintenance Manual (AMM) and Structural Repair Manual (SRM). The work is precision-critical — a poorly executed structural repair can compromise the entire aircraft.

Exams and syllabus: Licence S candidates must pass the CARS exam, Standards exam, and specialized Structures exams covering structural analysis, material science (aluminum alloys, composites, titanium), corrosion control, fasteners, adhesives, heat treatment, and NDT (non-destructive testing) methods. The Sky Licence question bank for Licence S contains over 300 questions across 7 chapters. The 7-chapter syllabus is the most focused of the three categories.

Difficulty: Licence S exams are considered the most technically demanding by many candidates. While the syllabus is narrow, the depth of knowledge required in areas like stress analysis, material properties, and repair design is significant. Questions often require candidates to calculate load paths, determine appropriate repair schemes, and interpret engineering drawings. Practical experience is especially important for Licence S — the theory only makes full sense when you have hands-on experience with the materials and techniques.

Career paths: Licence S engineers work at specialized structural repair shops, MRO heavy maintenance lines (especially C and D checks), aircraft manufacturing and assembly plants (Bombardier, Airbus Canada, De Havilland), OEM service centres, and airline engineering departments. Licence S is also valuable for those interested in aircraft modification and completion centres, where custom interiors and external modifications require structural engineering approval.

Salary expectations: Licence S engineers are well-compensated due to the specialized nature of their skills. Entry-level positions start around $55,000–$65,000. Experienced structures specialists earn $75,000–$95,000. Senior structural engineers and lead repair designers at major MROs or OEMs can earn $100,000–$130,000+. The premium reflects the high-stakes nature of structural repair work and the relative scarcity of qualified candidates.

Industry demand: Demand for Licence S is steady but more specialized than M or E. Major MROs consistently need structures specialists for heavy maintenance events. The growing use of composite materials in modern aircraft (carbon fibre fuselages on the 787 and A350) has created a niche for composite repair specialists with Licence S certification, and these skills are in particularly high demand.

Side-by-Side Comparison Table

Which Licence Should You Start With?

Choosing your first AME licence is a significant career decision. Here are the key factors to consider:

Start with Licence M if:

• You want the broadest career options. Licence M is the most versatile and in highest demand. It opens doors at airlines, MROs, flight schools, and everywhere in between.
• You enjoy working with your hands on mechanical systems. If the idea of overhauling an engine, rigging flight controls, or repairing landing gear excites you, M is the right path.
• You are unsure about your specialization. Licence M covers the widest range of topics, giving you exposure to many different areas before you decide to specialize.
• You want to work in general aviation. The M1 rating is the standard for GA and flight school maintenance.

Start with Licence E if:

• You have a background or strong interest in electronics. If you understand circuit theory, digital logic, and RF principles, Licence E will leverage your existing knowledge.
• You want to work at the cutting edge of aviation technology. Avionics is the fastest-evolving domain in aircraft maintenance, with new systems being certified every year.
• You prefer working with brains over brawn. Avionics work is less physically demanding than structural or mechanical work and more focused on diagnostic problem-solving.
• You want strong salary growth potential. Licence E compensation rises quickly with experience and specialization.

Start with Licence S if:

• You are passionate about materials and structural repair. If metallurgy, composite layup, and precision sheet metal work appeal to you, S is your path.
• You enjoy highly focused, precision-oriented work. Structural repair requires meticulous attention to detail and pride in craftsmanship.
• You already have sheet metal or composites experience. Many Licence S candidates come from aircraft manufacturing or heavy maintenance backgrounds.
• You want a niche skill that commands premium pay. Licence S engineers are harder to find, which means employers compete for qualified candidates.

Can You Hold Multiple AME Licences?

Yes — Transport Canada allows you to hold multiple AME licence categories simultaneously. You can earn your Licence M first, gain experience, and then add Licence E or Licence S by passing the additional exams and meeting the experience requirements. This is a common career progression for ambitious AMEs who want to maximize their marketability.

Holding multiple licences makes you significantly more valuable to employers. An M + E licence holder can certify both mechanical and avionics maintenance — a rare and highly sought-after combination. Similarly, M + S covers both general airframe maintenance and advanced structural repair. Employers often offer salary premiums for engineers with multiple licences because it reduces their need to assign different engineers to different tasks.

The typical path to multiple licences is:

1. Earn your first licence (usually M, given its breadth and demand)
2. Work for 2–4 years gaining practical experience in your primary category
3. Begin studying for the additional licence exams while working
4. Pass the required exams and accumulate the necessary cross-category experience
5. Apply for the additional licence endorsement from Transport Canada

Sky Licence covers all three categories — M, E, and S — making it the ideal platform whether you are pursuing your first licence or adding another category to your credentials.

CAR 573 and the Regulatory Framework

The regulatory basis for AME licences in Canada is found in CAR 573 — the section of the Canadian Aviation Regulations governing aircraft maintenance engineer licensing. CAR 573 defines the scope of each licence category, the experience requirements, and the privileges and limitations associated with each. All three licence categories require a thorough understanding of the applicable regulations, which is why the CARS exam is mandatory regardless of which licence you pursue.

For a complete breakdown of the CARS exam, including question format, key topics, and study strategies, read our CARS exam guide.

How Sky Licence Covers All Three Categories

Sky Licence provides comprehensive AI-powered exam preparation for Licence M (24 chapters, 1,200+ questions), Licence E (10 chapters, 600+ questions), and Licence S (7 chapters, 300+ questions). Our question banks are mapped to the Transport Canada TP14038E syllabus for each category, with adaptive learning algorithms that identify your weak areas and generate targeted practice questions.

Whether you are pursuing your first AME licence or adding an additional category, Sky Licence adapts to your specific needs. The AI Tutor can explain complex concepts — from turbine engine theory to RF signal propagation to composite repair schemes — in clear, exam-focused language. Progress tracking shows your performance across every chapter and learning objective, so you always know exactly where you stand and what needs more work.

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Summary: Making Your Decision

There is no universally "right" AME licence — the best choice depends on your interests, aptitudes, and career goals. Licence M offers the broadest opportunities and highest overall demand. Licence E offers the fastest-growing field with strong compensation. Licence S offers the most specialized and highest-paying niche for those with precision craftsmanship skills.

If you are still unsure, consider starting with Licence M. It is the most versatile foundation, and you can always add E or S later as your career interests crystallize. Whichever path you choose, the key to success is thorough exam preparation — and Sky Licence is built to help you achieve that.

For more background on the AME licensing process, eligibility, and training pathways, read our complete guide to getting your AME license in Canada.