Performance Class B (CS-23): Airworthiness Requirements
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.