Original subtitles

The radio navigation aids enable the crew to navigate and monitor

aircraft position.

The A320 is equipped with two Vors, 2 Dmes, 2 IL s s, one or

two AD FS depending on the airplane.

GPS equipped aircraft have no AD FS.

Each DME is in reality A5 channel time sharing unit.

One channel is associated with the VOR, one with the ILS and

the others are used for navigation.

The FMGC can automatically tune the VORDME and ILS for position,

updating and display purposes.

Note that the ADF cannot be auto tuned and is not used for

navigation by the FMGC.

The radio navigation itself is controlled by both FMG CS and

can be monitored through MCDU pages.

Either MCDU via the radio navigation page enables the crew

to manually tune a specific NAV aid, including the ADF, FM, GC.

Auto tuning continues normally in the background.

Note that when an ILS approach is selected, ILS one is

displayed on PFD one and ND 2.

ILS 2 is displayed on PFD 2 and ND one.

As you have seen in the EFIS chapter, the mode selector

enables the pilot to select different ND modes to display

flight plan and navigate data.

Plan mode is recommended when entering and checking the flight

plan.

However, NAVAID data cannot be displayed in this mode.

In all the other modes, ROWS ILS, ROWS VOR, ROWS NAV and ARC,

the navaids can be displayed provided the ADFVOR selectors

have been switched to VOR or ADF position.

Here as an example, the ROWS VOR mode is selected with ADF ONE

and VOR 2.

The ADF is shown as a green pointer here.

ADF ONE, VO, Rs are white pointers in this example VOR

two.

Note also that the Receiver one data is displayed on the left

side of the ND and the Receiver two data on the right side.

The associated NAV Aid data is displayed at the bottom of the

ND in their respective colours and sides.

Presented here are all the available modes for the

navigation display.

In the unlikely event of a double FMGC failure, the Backup

tuning mode provides radio navigation redundancy to the

crew.

The backup tuning mode is accessed via the Radio

Management Panels RMP for NAVAID tuning.

RMP one standby NAV keys are associated with VORD ME1 and ADF

one, while RMP 2 keys are associated with VORD ME2 and ADF

2.

Either RMP One or two can tune the ILS.

To access the backup tuning mode, the NAV key has to be

pressed.

When the backup tuning mode is selected, that is, the NAV key

illuminated, the control of the associated receivers is

transferred to the RMP and the NAV AID tuning capability of

both FM GCS is lost.

This is indicated on the MCDU by a change to the radio navigation

page, which shows only the titles in dull white.

To return the control to the FMGC, the NAV key has to be

pressed again.

Once backup tuning has been selected, the crew must select

the desired type of NAV, aid, BORILS or ADF.

The DDRMI is on the main instrument panel.

The DDRMI Digital Distance and Radio Magnetic Indicator

displays raw data from ADFVOR and DME sources and presents a

traditional radio magnetic indicator and bearing pointer

presentation.

Two bearing pointers are provided, each readily

identifiable by its shape with its radio source.

Each can display either VOR or ADF information depending on

selector position.

Each pointer has an associated control knob.

The left knob selects either VO R1 or ADF one.

The right knob selects VO R2 or ADF 2.

If installed here, VO R1 and VO R2 are selected.

The compass card displays the bearing information from Adiru 1

VOR 1 Pointer and data are shown on the navigation display

display BOR two data.

The left side of the ND navigation display shows

information from receiver one and the right side data from

receiver 2.

Note the symbol next to the VOR title.

It is a reduced scale representation of the number one

VOR single needle pointer.

Since the VOR data and the pointer is displayed, both

receivers consider the VOR signal as valid.

On the second line, the VOR identifier appears.

On the third line, the DME distance appears in green.

To see the NAV aids automatically tuned by the FMGC,

we have to call the RAD NAV radio navigation page.

Call the RAD NAV page.

You can see on the radio navigation page that the FMGC

has automatically tuned the VOR Lal on both receivers.

The identifiers are shown on the RAD NAV page and on the bottom

of the navigation display.

Note that the identifiers on the radio navigation page are in

small font.

Now we will manually tune VOR #2.

The identifier Mel is already typed into the scratch pad

inserted by selecting line key one right?

The VOR identifier on the MCDU is in large font, indicating a

manual selection on the navigation display.

This is confirmed by a tiny underlined M beside the VOR two

data location.

Because a valid signal has not been received from the VOR, the

associated data and pointer are not shown.

The number 2 radio is now receiving a valid signal from

the VOR.

The associated pointer and data are displayed on the navigation

display along with the M, again indicating that the VOR has been

manually tuned.

Since the VOR is not equipped with the DME, the DME indication

is replaced by green dashes.

Now select the ILS switch on the EFIS control panel.

On the PFD, you can check the ILS identifier, ICRR and the

frequency and the course.

The course is also indicated on the navigation display.

The check and the selection of the NAV aids is now complete.

The objective of the navigation accuracy check is to compare the

raw data from the tuned NAV aids with the corresponding flight

management computer data.

This check also has to be performed whenever the following

cases occur.

The progress page displays low accuracy NAV accuracy.

Downgrade message appears on the MCDU and on the ND prior to

beginning a descent.

To perform this check you have to use the selected navaids and

display them on the navigation display.

We have set the ND range to 80.

The VOR SPR has been manually tuned on receiver one and the

VOR PAS on receiver 2.

Note that the VOR PAS is the next two waypoint on the flight

plan.

There are two ways to do this check.

The first method is to compare the two waypoint distance, which

is flight management computer data with the corresponding NAV

and DME distance.

The second method is to insert a VORDME identifier in the bearing

distance 2 field on the progress page and to compare the computed

bearing distance with the raw data on the navigation display.

We have typed the VORDME identifier SPR in the scratch

pad for you.

Insert SPR in the bearing distance field.

The progress page now displays the computed bearing and

distance to the selected NAV aid.

The distance is shown on the navigation display and on the

progress page can be compared.

Whatever method is used.

If the error is less than one nautical mile, the check is

positive and the flight management position is reliable.

The SOP recommends to use the navigation display in arc or NAV

mode and managed lateral guidance.

If the error is greater than one nautical mile, you can consider

that the flight management position is not reliable.

In such a case, the SOP requires you to use raw data for

navigation and to monitor it.