ATA 34 - NAVIGATION

• Back up navigation: This procedure is used as a backup operation only in case of failure of both FMGCs, or failure of the MCDUs. Only the Radio Management Panel (RMP) 2 allows the tuning of F/O side receivers. Only RMP 1 allows the tuning of CAPT side receivers.

• Three Pitot probes provide total pressure to three Air Data Modules (ADMs), which convert this pressure into digital format: ARINC 429 to ADRIU.

• ADIRU 3 only receives the TAT from both TAT sensors 1. The probes are installed in such a way that their pressure lines do not require a water drain, except for that of the standby static ports.

• ALIGN IRS message disappears and IRs alignment starts. It takes 10 or 15 minutes depending on the latitudes range.

• As soon as the ISIS is energized, it shows the initialization display for 90 s. When the airspeed data is not valid, the airspeed scale is replaced by a red SPD flag.

• The spatial segment is composed of a constellation of 24 satellites. (20.500KM + 12 orbital hours)

• At least 4 satellite are need it to compute A/C position.

• CAPT and F/O Radio Management Panels (RMPs) for ILS back-up tuning.

• The ILS 1 information is displayed on PFD 1 and ND 2. The ILS 2 information is displayed on PFD 2 and ND 1.

• Either RMP controls both MMR units, if NAV mode is activated by selecting NAV key on RMP 1 and 2. RMP 3 it is not used for back-up tuning.

• The GPS function provides three-dimensional aircraft position, velocities and exact time used for hybrid computations by the three ADIRUs.

• The antenna scans 180 degrees sector in azimuth and has a tilt coverage of + or - 15.

• The wind shear function is automatically activated below 2300 ft RA and one of each qualifier A and on of each qualifier B have to be valid.

• When both EFIS control panels are in PLAN mode, the WXR/PWS transceiver is de-energized.

• The A/C height data is displayed on the PFDs for heights less than or equal to 2.500 ft.

• The operating range of the antenna according to the aircraft attitude is limited to + or – 30 for pitch and roll.

• The TCAS indications appear on the PFDs and the NDs.

• The EGPWS receives the PredictiveWindShear (PWS) alerts from the weather radar hazard bus to determine the priority. The PWS has priority over EGPWS modes. The Flight Warning Computers (FWCs) send a discrete to the EGPWC to inhibit all warnings when a stall or wind shear warning is triggered.

• The DME distance is shown on the PFD if the ILS display is selected via LS P/B and on the ND if the ADF/VOR selector is set to VOR. The DME distance is also shown on the two windows of the DDRMI.

• From each MCDU both DMEs can be manually tuned through their own side FMGC (via port A). Back-up tuning direct from RMP 1+2 only.

• MRK beacon is active only in VOR 1.

• A/C is equipped with only 1 ADF.

• ADMs (Air Data Module) get power from ADIRUs.

• We have 7 ADMs in total, all interchangeable

• ISIS gets data directly from standby pitot, standby static port and IR data from ADIRU 1

or ADIRU 3. ISIS is not connected to CFDIU or MCDU

TRICK: if we press both “BUGS” and “LS” button on ISIS unit we get access to ISIS menu mode (accessible on ground only)

• ISIS gets data from MMR 1 only.

• MMR (Multi Mode Receiver) receives and computes data from ILS (LOC - GS) and from GPS.

• A/C position is calculated computing ADIRUs and GPS data for a hybrid data output in order to maximize precision. In case of GPS fault, ADIRUs are capable of compute positional data by themselves.

• ATC, DME and TCAS use a suppressor coaxial cable since they transmit on the same frequency range, that is to avoid any signal interference (noise).

• Transponder has 4 antennas, 2 on the top and 2 on the bottom of the fuselage.