-
If the current position mode is GPIRS it becomes GPIRS/LOC and the nav mode on the POSITION MONITOR page becomes N IRS/GPS/LOC.
-
If the current position mode is IRS/DME/DME, it becomes IRS/DME/LOC and the nav mode on the POSITION MONITOR page becomes N IRS/DME/LOC.
-
If the current position mode is IRS/VOR/DME, it becomes IRS/VOR/LOC and the nav mode on the POSITION MONITOR page becomes N IRS/VOR/LOC.
-
If the current position mode is IRS only, it becomes IRS/LOC and the nav mode on the POSITION MONITOR page becomes N IRS/LOC.
(e)
Inertial only This mode of navigation is used if neither the VOR/DME/INERTIAL nor the DME/DME/INERTIAL nor the GPS/INERTIAL modes have been chosen and at least one IRS is valid. When selected, the mode displayed on the POSITION MONITOR page is N IRS where N is the number of IRs used to determine the inertial position.
(3) Class of navigation (Ref. Fig. 011) Two classes of navigation are defined. They reflect the fact that the system respects the required navigation accuracy. If this requirement is satisfied, the class is HIGH. Else, the class is LOW. The current navigation accuracy requirement is expressed by the current required accuracy threshold. This value can be entered or modified by the pilot on the PROGRESS page. If there is no pilot entered value, a system value is computed in the following order of precedence:
-Use the RNP type coded in the navigation database for the corresponding leg or route, if defined.
-The default RNP is determined based on active flight area or the selected type of approach (when flight area is Approach) as defined in the following table.
-------------------------------------------------------------------------------| Nav Flight Area | RNP | |-----------------------------------|-----------------------------------------| | Take off | OPC Take off default RNP value (1 NM) | | Terminal | OPC Terminal default RNP value (1 NM) | | En Route | OPC En Route default RNP value (2 NM) | | Oceanic | OPC Oceanic default RNP value (2 NM) | | Approach with GPS approach | OPC GPS Approach default RNP value | | | (0,3 NM) | | Approach with LOC-based precision | OPC Precision Approach default RNP value| | approach (ILS, LOC, IGS, LDA, SDF)| (0,5 NM) | | Approach with VOR/RNAV approach - | MAXI OPC Non Precision Approach value | | using specified navaid for | Sensor EPE (0,5 NM) | | position updating | | | Approach with VOR/RNAV approach - | OPC Non Precision Approach value | | not using specified navaid for | (0,5 NM) | | position updating | | | All other approach types | OPC Non Precision Approach value | | | (0,5 NM) | -------------------------------------------------------------------------------
R Class of Navigation Figure 011
R 1EFF : 106-149, 151-199, 211-299, 301-399, 1 22-72-00Page 26 1401-499, 1Config-2 Aug 01/05 1 1 1CES 1 A 'PROCEDURE RNP IS XX.XX' message (XX.XX is the current RNP value) is displayed in the scratchpad if:
-a RNP type is manually entered by the pilot
-
and a navigation data base RNP value is defined for the active leg or route
-
and the pilot entered value is greater than the current RNP value.
Any subsequent reduction of the system RNP type below the pilot
entered value shall re-initiate this announcement.
An 'AREA RNP IS XX.XX' message (XX.XX is the current RNP value) is
displayed in the scratchpad if:
-an RNP type is manually entered by the pilot
-
and no navigation data base RNP value is defined for the active leg or route (the corresponding OPC default RNP value is currently used)
-
and the pilot entered value is greater than the current RNP value Any subsequent reduction of the system RNP type below the pilot entered value shall re-initiate this announcement. The class is HIGH whenever the estimated position error is less than the current required accuracy threshold. A level of confidence on the GPIRS position is determined as a function of the GPIRS position accuracy and integrity. The confidence status is GPS PRIMARY when both accuracy and integrity requirements are met (accuracy is HIGH and integrity requirements of TSO-C129 are met). When GPS/INERTIAL mode is lost while GPS confidence level was GPS PRIMARY, the GPS PRIMARY LOST message is displayed on the MCDU and ND. When GPS/INERTIAL mode becomes active and the class of navigation is HIGH, the GPS PRIMARY message is displayed on the MCDU and ND. The GPS PRIMARY and GPS PRIMARY LOST messages can only be displayed when GPS option is active. When the class of navigation is not HIGH, it is LOW. The class of navigation is displayed continuously on the PROG page. When the class of navigation is downgraded from HIGH to LOW, the message NAV ACCUR DOWNGRAD is displayed on the EFIS and MCDU. When the class of navigation is upgraded from LOW to HIGH, the message NAV ACCUR UPGRAD is displayed on the EFIS and MCDU. However, for operational reason, the NAV ACCUR UPGRAD message is never displayed while on the ground. If one of these messages is to be displayed but the other is already displayed, then the latter message is deleted. To avoid disturbing the crew in approach, special logics apply at transition to approach Flight area:
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