Title: Airbus A320: Understanding SRS GA, Managed Speed/Mach, and VAPP Memorization
Introduction
As professional pilots operating Airbus aircraft, a comprehensive understanding of the various systems and procedures is crucial for safe and efficient flight. Let's delve into the specifics of the SRS GA (Slats/Flaps System and Go-Around mode), Managed Speed/Mach modes, and the memorization of VAPP (Approach Reference Speed) at 700 feet RA (Radio Altitude).
SRS GA Engagement
When the SRS GA is engaged, it signifies the activation of the Slats/Flaps System and the initiation of the Go-Around mode. This mode is crucial during takeoff or in the event of a go-around situation. The Memorized aircraft speed at SRS GA engagement plays a pivotal role in ensuring a smooth transition during critical phases of flight.
VAPP Memorization at 700 ft RA
The lower limit of the target speed during the approach phase is set by the VAPP memorized at 700 feet RA. This ensures that the aircraft maintains a minimum reference speed during the approach, contributing to stabilized and controlled descents.
Higher Limit Calculation
The higher limit of the target speed is determined by the lowest value between:
1. VLS + 25 kt (or VLS + 15 kt OEI): VLS (Low-Speed Protection) is increased by either 25 knots or 15 knots in the case of an engine-out scenario, providing an additional safety margin.
2. VMAX - 5 kt: The maximum operating speed (VMAX) is reduced by 5 knots, offering a conservative limit to prevent excessive speeds during approach and landing.
Managed Speed/Mach Modes
Engaging F-G/S, G/S, LAND, FLARE, or ROLL OUT triggers the Managed Speed/Mach modes. When VAPP is memorized at 700 ft RA, even if the Flight Management System (FMS) loses the VAPP below this altitude, the managed speed target will still be computed. This feature ensures that the aircraft maintains the desired approach speed, enhancing overall system reliability.
Conclusion
In conclusion, the interaction between SRS GA, Managed Speed/Mach modes, and VAPP memorization at 700 ft RA forms a critical part of the Airbus advanced flight control system. Pilots must master these procedures to ensure precise and safe handling of the aircraft during takeoff, approach, and landing phases, contributing to the overall safety and efficiency of Airbus operations.