Airworthiness Manual Chapter 523 Subchapter D - Design and Construction - Canadian Aviation Regulations (CARs)

Canadian Aviation Regulations (CARs)

Content last revised: 2021/09/21

Legacy sections

  • 523.1301-1 - Aeroplane Operation After Ground Cold Soak
  • 523.1457 - Cockpit Voice Recorders
  • 523.1459 - Flight Data Recorders
  • 523.1529 - Instructions for Continued Airworthiness


  • A (523.2000-523.2010),
  • B (523.2100-523.2165),
  • C (523.2200-523.2270),
  • D (523.2300-523.2335),
  • E (523.2400-523.2440),
  • F (523.2500-523.2550),
  • G (523.2600-523.2620)



Subchapter D - Design and Construction

523.2300 Flight Control Systems

  • (a) The applicant must design aeroplane flight control systems to:
    • (1) Operate easily, smoothly, and positively enough to allow proper performance of their functions.
    • (2) Protect against likely hazards.
  • (b) The applicant must design trim systems, if installed, to:
    • (1) Protect against inadvertent, incorrect, or abrupt trim operation.
    • (2) Provide a means to indicate:
      • (i) The direction of trim control movement relative to aeroplane motion;
      • (ii) The trim position with respect to the trim range;
      • (iii) The neutral position for lateral and directional trim; and
      • (iv) The range for take-off for all applicant requested centre of gravity ranges and configurations.

(effective 2021/09/21)

523.2305 Landing Gear Systems

  • (a) The landing gear must be designed to:
    • (1) Provide stable support and control to the aeroplane during surface operation; and
    • (2) Account for likely system failures and likely operation environments (including anticipated limitation exceedances and emergency procedures).
  • (b) All aeroplanes must have a reliable means of stopping the aeroplane with sufficient kinetic energy absorption to account for landing. Aeroplanes that are required to demonstrate aborted take-off capability must account for this additional kinetic energy.
  • (c) For aeroplanes that have a system that actuates the landing gear, there is:
    • (1) A positive means to keep the landing gear in the landing position; and
    • (2) An alternative means available to bring the landing gear in the landing position when a non-deployed system position would be a hazard.

(effective 2021/09/21)

523.2310 Buoyancy for Seaplanes and Amphibians

Aeroplanes intended for operations on water, must:

  • (a) Provide buoyancy of 80 percent in excess of the buoyancy required to support the maximum weight of the aeroplane in fresh water; and
  • (b) Have sufficient margin so the aeroplane will stay afloat at rest in calm water without capsizing in case of a likely float or hull flooding.

(effective 2021/09/21)

Occupant System Design Protection

523.2315 Means of Egress and Emergency Exits

  • (a) With the cabin configured for take-off or landing, the aeroplane is designed to:
    • (1) Facilitate rapid and safe evacuation of the aeroplane in conditions likely to occur following an emergency landing, excluding ditching for level 1, level 2 and single engine level 3 aeroplanes.
    • (2) Have means of egress (openings, exits or emergency exits), that can be readily located and opened from the inside and outside. The means of opening must be simple and obvious and marked inside and outside the aeroplane.
    • (3) Have easy access to emergency exits when present.
  • (b) Aeroplanes approved for aerobatics must have a means to egress the aeroplane in flight.

(effective 2021/09/21)

523.2320 Occupant Physical Environment

  • (a) The applicant must design the aeroplane to:
    • (1) Allow clear communication between the flight crew and passengers;
    • (2) Protect the pilot and flight controls from propellers; and
    • (3) Protect the occupants from serious injury due to damage to windshields, windows, and canopies.
  • (b) For level 4 aeroplanes, each windshield and its supporting structure directly in front of the pilot must withstand, without penetration, the impact equivalent to a two-pound bird when the velocity of the aeroplane is equal to the aeroplane’s maximum approach flap speed.
  • (c) The aeroplane must provide each occupant with air at a breathable pressure, free of hazardous concentrations of gases, vapours, and smoke during normal operations and likely failures.
  • (d) If a pressurisation system is installed in the aeroplane, it must be designed to protect against:
    • (1) Decompression to an unsafe level; and
    • (2) Excessive differential pressure.
  • (e) If an oxygen system is installed in the aeroplane, it must:
    • (1) Effectively provide oxygen to each user to prevent the effects of hypoxia; and
    • (2) Be free from hazards in itself, in its method of operation, and its effect upon other components.

(effective 2021/09/21)

Fire and High-Energy Protection

523.2325 Fire Protection

  • (a) The following materials must be self-extinguishing:
    • (1) Insulation on electrical wire and electrical cable;
    • (2) For levels 1, 2, and 3 aeroplanes, materials in the baggage and cargo compartments inaccessible in flight; and
    • (3) For level 4 aeroplanes, materials in the cockpit, cabin, baggage, and cargo compartments.
  • (b) The following materials must be flame resistant:
    • (1) For levels 1, 2 and 3 aeroplanes, materials in each compartment accessible in flight; and
    • (2) Any equipment associated with any electrical cable installation and that would overheat in the event of circuit overload or fault.
  • (c) Thermal/acoustic materials in the fuselage, if installed, must not be a flame propagation hazard.
  • (d) Sources of heat within each baggage and cargo compartment that are capable of igniting adjacent objects must be shielded and insulated to prevent such ignition.
  • (e) For level 4 aeroplanes, each baggage and cargo compartment must:
    • (1) Be located where a fire would be visible to the pilots, or equipped with a fire detection system and warning system; and
    • (2) Be accessible for the manual extinguishing of a fire, have a built-in fire extinguishing system, or be constructed and sealed to contain any fire within the compartment.
  • (f) There must be a means to extinguish any fire in the cabin such that:
    • (1) The pilot, while seated, can easily access the fire extinguishing means; and
    • (2) For levels 3 and 4 aeroplanes, passengers have a fire extinguishing means available within the passenger compartment.
  • (g) Each area where flammable fluids or vapours might escape by leakage of a fluid system must:
    • (1) Be defined; and
    • (2) Have a means to minimise the probability of fluid and vapour ignition, and the resultant hazard, if ignition occurs.
  • (h) Combustion heater installations must be protected from uncontained fire.

(effective 2021/09/21)

523.2330 Fire Protection in Designated Fire Zones and Adjacent Areas

  • (a) Flight controls, engine mounts, and other flight structures within or adjacent to designated fire zones must be capable of withstanding the effects of a fire.
  • (b) Engines in a designated fire zone must remain attached to the aeroplane in the event of a fire.
  • (c) In designated fire zones, terminals, equipment, and electrical cables used during emergency procedures must be fire-resistant.

(effective 2021/09/21)

523.2335 Lightning Protection

The aeroplane must be protected against catastrophic effects from lightning.

(effective 2021/09/21)