Performance Class B (CS-23): Climb, Cruise, and Descent Theory
En-Route Climb (AEO)
All Class B aircraft must be able to climb to a safe cruising altitude.
- Minimum Gradient: typically 300 ft/min rate of climb at sea level or a specified gradient at a higher altitude (e.g., 5,000 ft or MSA).
En-Route (One Engine Inoperative - OEI)
Single-Engine Aircraft
- If the engine fails, the aircraft will descend.
- Requirement: The flight must be planned such that, in the event of engine failure, the aircraft can glide to a suitable landing site.
- Cloud Ceiling: Operations on top of clouds are restricted if the pilot cannot descend visually in an emergency.
Multi-Engine Aircraft
- Must be able to continue flight or land safely.
- Service Ceiling (OEI): The altitude where the rate of climb is 50 ft/min.
- Route Requirement: The aircraft must be able to maintain an altitude above the Minimum Safe Altitude (MSA) along the route, usually 1,000 ft above terrain (2,000 ft in mountainous areas).
- If the aircraft cannot maintain MSA on one engine, it must obey restrictions similar to single-engine aircraft (visual contact with terrain, proximity to divert fields).
Descent and Landing
The descent planning must account for:
- Wind: Headwinds increase the descent angle relative to the ground.
- Power: Descent is usually powered to manage engine temperatures (avoiding shock cooling).
- Landing Mass: Must be below the Maximum Structural Landing Mass (MSLM) and the Performance Limited Landing Mass (PLLM) at the destination.