RNP P/B:
When selected ON, 
the L/DEV display appears
on PFD if conditions for
display are met

Note: On later standards of equipment, the L/DEV symbol will appear automatically. No RPN P/B will need to be installed

XTK with 2 digits after the dot when RNP ≤ 0.3 and below Transition Altitude, whatever the RNP P/B position.
When the RNP P/B is selected (“ON” label illuminated blue), the EIS2 internal logics for the display of the L/DEV scale are enabled.
The EIS2 displays L/DEV if one of the following conditions is met:
. A/C is on ground
Note: On ground and during TO roll, the L/DEV remains centered and is temporarily out of view between 50 to 90 kt.
. A/C is below transition altitude climbing
Note: If necessary, the Transition Altitude may be modified prior to departure on PERF T/O page or prior starting the approach on PERF APPR page.
. When a Non Precision Approach is selected on FMS ARRIVAL page and:
o  A/C is in the FMS approach area (5 NM to the first approach waypoint of the FMS F-PLN), or

o  The FMS approach phase is ACTIVATED, or

o  FINAL mode is armed or engaged (APPR P/B selected) 

When the cross-track error is more than 0.2NM left or right, the deviation index is replaced
by a half-box displayed on the corresponding dot. 
Full scale is ± 0.2 NM, 1 dot = 0.1 NM
If the LS P/B is pressed on the FCU, the L/DEV scale is inhibited.

-29 -
6. RNP AR Instrument procedures
Getting to grips with RNP AR

6. RNP AR INSTRUMENT PROCEDURES
6.1. RNP AR INSTRUMENT PROCEDURE DESIGN
RNP AR (SAAAR or equivalent) are designed using criteria of FAA Order  8260.52. or ICAO
Manual for Implementation of the Required Navigation Performance.
The flight path is constructed with sequences of TF-RF legs or RF-RF legs.

TF LEG

RF LEG
Radius
ARC
center

RF LEG
Sequences of TF-TF legs are normally not used as the waypoint fly-by transitions will be
calculated by the FMS as a function of the aircraft GS.
Nevertheless, some RNP AR procedures not requiring RF capability can be published with
sequences of TF legs. 
In the Final approach segment, fly-by turns are normally not authorized, but RF legs can be
used.

The protection area along the flight path has a semi-width equal 2xRNP.
The RNP value is in the range:   0.3 ≥ RNP ≥ 0.1
Only the obstacles within the 4xRNP corridor need to be considered for obstacle clearance.

-30 -
6. RNP AR Instrument procedures

In the initial and intermediate approach segments the Required Obstacle Clearance (ROC) is
1000ft and respectively 500ft, values that are quite standard for any NPA.
　
中國航空網 www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：getting to grips with RNP AR Required Navigation Performance(20)