(d) Display (Ref. Fig. 011) The selection of the LAND mode is indicated by:
-
illumination of the APPR pushbutton switch on the FCU
-
illumination of various indications on the flight mode
annunciator (FMA) section of the PFD. These indications are:
-
during the arming phase: . cyan G/S indication in the lower part of the section corresponding to the longitudinal modes . cyan LOC indication in the lower part of the section corresponding to the lateral modes. In addition, the active support mode indication remains visible (in green) until the LOC or GLIDE capture is effective.
-
during the capture phase, the indications are changed into:
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Active LOC and GLIDE Modes - Capture Conditions
Figure 009
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LAND TRACK Logic
Figure 010
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FMA Displays
Figure 011
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green LOC* indication : the lateral support mode is disengaged and the corresponding mode indication is cancelled. Green G/S* indication : the longitudinal support mode is disengaged and the corresponding mode indication is cancelled. The LOC* indication can be displayed at the same time as the cyan G/S indication (G/S mode armed) but the G/S capture phase can start only after the LOC capture phase except when the GLIDE BEFORE LOC pin program is activated.
-
during the track phase and above 400 ft. the indications are replaced by: LOC (green) G/S (green)
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during the track phase and below 400 ft. the green LOC and G/S indications are replaced by the green LAND indication across the line dividing the two sections corresponding to the longitudinal and lateral mode annunciations.
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in flare phase, the green LAND indication is replaced by the green FLARE indication.
-
in ground roll out phase, the FLARE indication is replaced by
the green ROLL OUT indication. In addition, the landing capability is displayed on the PFD, as soon as the LAND mode is selected, by the following indications: CAT 1 CAT 2 CAT 3 SINGLE CAT 3 DUAL
(e) Command generation
1 Lateral axis
_ (Ref. Fig. 012) The following figure gives the computation principle in the various phases associated with LOC axis capture and track, alignment and roll out. These computations are characterized by:
-filtering of the metric deviation from the ILS receiver and the estimated lateral speed. This enables to obtain a guidance signal which partly cancels the LOC noises and the data derivatives coming from the IRS.
-utilization for computation of the distance to the runway threshold, of estimated distance to LOC transmitter delivered by the FM part.
a LOC capture phase
_ (Ref. Fig. 013) The computation principle of the guidance law is given in figure.
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LOC Law - Computation Principle
Figure 012
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LOC CPT Control Law
Figure 013
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b_ LOC track phase
(Ref. Fig. 014)
The computation principle of the law in the LOC TRACK phase
is given in figure.
c Align phase
_ (Ref. Fig. 014) The computation principle of the guidance law is given in figure. The deviation between the aircraft heading and the runway heading (d PSI) is used to place the aircraft parallel to the runway centerline before touchdown. This law is also characterized by the acquisition of an estimated skidding term.
d Roll out phase
_ (Ref. Fig. 015) The computation principle of the guidance law is given in figure.
2 Longitudinal axis
_
a GLIDE capture and track phase
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