The Ground Speed Mini (GS Mini) function is designed to maintain the aircraft’s energy above a minimum level by accounting for gusts and wind changes, ensuring a stable and safe approach speed. By dynamically adjusting the managed speed target to account for wind changes, it helps maintain the necessary energy levels for a safe landing.
- Managed speed target provided by GS Mini is generally higher than Vapp to maintain energy of aircraft above calculated minimum level. (This means aircraft actual approach speed is higher than calculated one!)
- Flight guidance continuously computes the manage speed target as per wind changes
GS Mini Calculations
| Managed Speed Target = Vapp + K (current head wind – tower reported head wind)
K factor for target managed speed computation depends on CEO or NEO type |
| Vapp = Vls + 1/3 tower reported head wind |
| GS Mini = Vapp – tower reported head wind |
GS Mini Managed Speed Target Example:
Conditions: Landing Runway 27, Winds 270/15, Vls 125, A320 CEO, Spot Head Winds 25kts
- Vapp: 125+5 = 130
- GS Mini: 130 – 15 = 115 (minimum ground speed that aircraft will maintain)
- Managed Speed Target: 130+1(25-15) = 140
GS Mini computed managed speed target has 2 limits:
- Minimum Correction Value: 0 knots (no wind or tailwind conditions)
- Maximum Correction Value: +15 knots (maximum increase allowed due to headwind component adjustments)
GS MINI NEO vs. CEO
The A320 NEO has different speed management characteristics compared to the CEO due to the presence of the Lift Improvement Package (LIP) in the NEO, which is particularly beneficial at higher landing flap angles (40 degrees for the NEO). Due to higher degree of flaps and overall augmented lift, lower approach speed is possible in Airbus A320 NEOs. As a result, the K factor for the managed speed computation is different:
- NEO: K factor of 1/3, allowing for more thrust variation.
- CEO: K factor of 1.