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Some of the RNAV STAR's at Dubai have an RNP of 5.
Reading elsewhere it states the the minimum RNP for an arrival is 1.
What should you put in the box 1 or 5?
Thanks in advance for your replies
glad rag
21st Feb 2009, 15:43
PMSL!!
Well I would but according to "der pprune'er" my reply was "short" whatever that means these days.:confused:
kotakota
21st Feb 2009, 15:45
Don't know what you are operating , but does your FMC not have the required values in the database ?
FE Hoppy
21st Feb 2009, 23:25
If you are flying a published procedure with a required navigation performance of 5 then you are only interested in being able to maintain an actual navigation performance (estimate of position uncertainty) of less than 5 and require alerting to when you are not able to maintain that performance therefore the only RNP value of any use is 5.
to maintain an actual navigation performance (estimate of position uncertainty) of less than 5 and require alerting to when you are not able to maintain that performance
That is the case for basic 5.0 RNAV , but Eurocontrol is active in pushing
1.0 P-RNAV initially on high demand routes, obviously airlines will only be able operate certified compliant airplanes with this capability. 0.3 P-NAV is also around the corner.
Thanks for the answers. It just seems odd to have such a high RNP figure for a STAR. I always thought that you had 10 for the atlantic, 5 for airways, 1 for a STAR and 0.3 for an approach.
FE Hoppy
22nd Feb 2009, 17:26
Remember that RNP is a specific requirement for the airspace you are in. There is no need to make the RNP low if the traffic density is low and there are no obstacles to consider.
Why make the procedures overly restrictive if it isn't needed?
The P-RNAV concept was and is only a stepping stone to RNP. The arrivals are designed with rnp 1 in mind to best meet flow demands and obstacle requirements.
In the honeywell Primus epic FMS the default values are .3 Approach. 1 terminal and 2 En-route changing to 10 in remote areas. These are just the default values set by Honeywell they have nothing to do with the actual RNP values for the airspace you are in. For example B-RNAV requires RNP 5 but the default value in the fms is RNP 2. Either you leave it and accept an alert for the wrong value or change it to reflect the actual requirement.