Performance Class B (CS-23): Airworthiness Requirements

032-02-01Pablo Asensio Martínez2026-04-011 min

Certification Basis (CS-23)

Performance Class B generally covers aeroplanes certified under CS-23 (Normal, Utility, Aerobatic, Commuter Categories).

  • Maximum Take-Off Mass (MTOM): $\le$ 5,670 kg.
  • Passenger Seating: $\le$ 19.
  • Engines: Propeller-driven (Single or Multi-engine).

Key Performance Requirements

Unlike Class A, Class B aeroplanes are not guaranteed to maintain performance after an engine failure.

Stall Speed Limit

For single-engine aeroplanes, the stall speed in the landing configuration ($V_{S0}$) often must not exceed 61 knots (CAS) to ensure a survivable forced landing speed.

Climb Requirements (All Engines Operating)

  • Must demonstrate a steady climb gradient at sea level (ISA) of at least:
    • 4.0% (Single Engine).
    • 8.3% or specific formula (Multi-engine).

Climb Requirements (One Engine Inoperative)

  • Single Engine: No requirement to climb after engine failure.
  • Twin Engine (Commuter Category): Must have a measurable climb gradient at 400 ft above take-off surface.
  • Twin Engine (Normal/Utility): May not have a positive climb gradient at MTOM. If they cannot climb, they must have a determined "negative climb" (drift down) path.

Equipment

Basic instrumentation is required, but systems redundancy (like dual hydraulic or electrical sources) is less stringent than for Class A.