Getting to Grips with Approach-and-Landing Accidents Reducti(150)

The Final Approach Speed
Page 1

AIRBUS INDUSTRIE
    Flight Operations Support

The final approach speed V APP can be determined based on V REF or V LS, as follows:
V APP = V REF + Corrections

The speed corrections on V REF account for:
.  Aircraft configuration ( CONF CORR ):
.  landing with less than full flaps; or,
.  abnormal configuration;

.  Operational factors:
.  WIND CORR for wind component, gusty crosswind or suspected wind shear; and,
.  + 5 kt for use of A/THR in SPD mode or if significant ice accretion is suspected.

or,
V APP = V LS + Increments + Corrections

The speed increments on V LS account for:
.  
Configuration conditions that are not included in the computation of the V LS.

The speed corrections on V LS account for:

.  
Operational factors only:

.  WIND CORR for wind component, gusty crosswind or suspected wind shear; and,
.  + 5 kt for use of A/THR in SPD mode or if significant ice accretion is suspected.
(the speed correction for ice accretion is
+ 5 kt or + 10 kt, depending on aircraft model).

The resulting final approach speed V APP provides the best compromise between handling qualities (stall margin and/or maneuverability / controllability) and landing distance.
For clarity and commonality among various Airbus models, the following overview and discussion refers only to the computation of V APP based on V REF.
                                                                                       Getting to Grips with                                            Approach-and-Landing Accidents Reduction

Factors Affecting the Final Approach Speed
The following speed corrections should are not be added, only the highest speed correction should be considered (unless otherwise stated in the applicable FCOM and QRH):
.  
Wind correction;

.  
Speed correction for ice accretion;

.  
Speed correction for the use of the A/THR in SPD mode or for autoland;

.  
Speed correction for forecast downburst / wind shear conditions.

The FCOM and QRH provide the rules applicable for the aircraft type and model.
Gross weight:
Because V REF is referenced to the stall speed (V S MIN or V S 1g), V REF depends on the gross weight.
The FCOM and QRH provide V REF tables for normal landings and overweight landings.
Wind conditions:
The wind correction on the final approach speed provides an additional margin relative to the stall speed, to cope with speed excursions caused by turbulence and wind gradient.
Airbus Industrie uses the following wind corrections (WIND CORR):
.  
A320/A330/A340 series:

.  1/3 of the headwind component (excluding the gust), limited to 15 kt;

.  
A310/A300-600:

.  (1/3 of the tower average wind) or (the gust increment), whichever is higher, limited to 15 kt; or,
　
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