What’s the difference between B1 and B2 aircraft Engineers?

B1 and B2 engineers are categories of aircraft maintenance licenses as defined by the European Aviation Safety Agency (EASA). These licenses delineate specific areas of expertise and responsibilities, each essential for maintaining the safety and functionality of aircraft.

B1 Engineers: Mechanical and Electrical Systems Specialists


B1 engineers are primarily responsible for the mechanical and electrical systems of an aircraft. Their expertise spans a broad range of components, ensuring the aircraft’s structural integrity and operational efficiency.

Areas of Expertise:

  • Airframe: Structural components of the aircraft, including the fuselage, wings, and tail assembly. B1 engineers inspect and repair any damage or wear to these parts.
  • Engines: Maintenance of the aircraft’s powerplants, whether turbine or piston engines. This includes inspections, repairs, and overhauls to ensure engine reliability and performance.
  • Mechanical Systems: This encompasses landing gear, flight controls, hydraulic and pneumatic systems. B1 engineers ensure these systems are functioning correctly and efficiently.
  • Electrical Systems: While B1 engineers are not avionics specialists, they handle electrical systems related to mechanical components, such as lighting, cabin pressurization, and power distribution systems.


  • B1.1: Maintenance on fixed-wing aircraft with turbine engines (e.g., commercial jetliners).
  • B1.2: Maintenance on fixed-wing aircraft with piston engines (e.g., smaller general aviation aircraft).
  • B1.3: Maintenance on rotary-wing aircraft with turbine engines (e.g., helicopters).
  • B1.4: Maintenance on rotary-wing aircraft with piston engines (e.g., smaller helicopters).


B1 engineers are authorized to certify maintenance work on the airframe and engine systems, ensuring these critical components meet safety and operational standards.

B2 Engineers: Avionics Specialists


B2 engineers specialize in the avionics systems of aircraft. Avionics encompasses the electronic systems used for communication, navigation, and the management of various aircraft systems.

Areas of Expertise:

  • Navigation Systems: Maintenance and repair of systems that provide navigational information, such as GPS, VOR, and ILS. These systems are crucial for safe and accurate flight operations.
  • Communication Systems: Ensuring the proper functioning of communication devices, including radios, transponders, and satellite communication systems. Effective communication is vital for air traffic control and aircraft coordination.
  • Radar Systems: Maintenance of radar equipment used for weather detection and collision avoidance. This includes both primary and secondary surveillance radar systems.
  • Flight Management Systems (FMS): B2 engineers ensure that the software and hardware of FMS, which automate various in-flight tasks, are functioning correctly.
  • Auto-pilot Systems: Overseeing the proper operation of auto-pilot and related control systems that manage the aircraft’s trajectory.
  • Electronic Instruments: Maintenance of cockpit instruments and displays, which provide pilots with critical flight information.


B2 engineers are authorized to certify work on avionics systems. While they do not typically work on airframe or engine systems, their role is crucial for ensuring that all electronic systems are operating correctly.

Summary of Key Differences:

B1 Engineers:

  • Focus on mechanical and electrical systems related to airframe and engines.
  • Responsible for structural integrity, engine performance, and mechanical systems.
  • Can certify work on airframe and engine systems.
  • Subcategories include B1.1 (fixed-wing turbine), B1.2 (fixed-wing piston), B1.3 (rotary-wing turbine), B1.4 (rotary-wing piston).

B2 Engineers:

  • Specialize in avionics, dealing with electronic systems and instruments.
  • Responsible for navigation, communication, radar, and auto-pilot systems.
  • Can certify work on avionics systems.
  • Focused solely on the electronic and electrical aspects of the aircraft.

Both B1 and B2 engineers are integral to maintaining the safety and airworthiness of aircraft, each bringing their specialized skills to ensure comprehensive maintenance coverage.