RNP and ANP

[code0]

Greetings guys!

This is the ND of Boeing 737-800



http://flightlevel350.tumblr.com/image/29556344615

Bottom Arrow:
Could anybody tell me what is RNP and ANP - Required/Actual Navigational Performance exactly? and how it can be used in an approach? or do you use during cruise, etc?

Top Arrow:
what is TRNB 0152.4z ?

many thanks in advance!

[Denti]

Obviously a flightsim question, please mark that next time in the title.

Anyway, RNP is the Required Navigation Performance for the current environment, ANP is the Actual Navigation Performance.

TRNB is the next waypoint and the time the aircraft arrives at that waypoint is 0152.4z.

[code0]

Thanx Denti for the reply and yeah i ll mention that next time!

[aterpster]

Where is TRNB? I can't find it in a worldwide database.

[Torque Tonight]

4 letter identifiers are normally ICAO airport codes, with TR being the prefix for Montserrat. However there doesn't seem to be a TRNB and it would be unusual (but quite possible) to be navigating directly to an airfield reference point. TRNB could be a user created waypoint or may just be random letters to demonstrate elements of the display.

[Pub User]

It could be the older Boeing system of using 'NB' after the name of an NDB. Is there a 'TR' NDB in your database?

[FlightPathOBN]

Check this site. It appears the ARINC coding is incorrect, at UKBB/KPB, the mistake is that the TR NDB is coded as IF, not a TF leg.

Here is a low cost explanation of RNP and ANP....
from 737.org

Actual Navigation Performance (ANP) is the FMC's estimate of the quality of its position determination. The FMC is 95% certain the the aircraft's actual position lies within a circle of radius ANP centred on the FMC position. Therefore the lower the ANP, the more confident the FMC is of its position estimate.

Required Navigation Performance (RNP) is the desired limit of navigational accuracy and is specified by the kind of airspace you are in. Eg for BRNAV above FL150, RNP=2.00nm. The RNP may be overwritten by crew.

ACTUAL should always be less than RNP.

[c100driver]

Actual Navigation Performance (ANP) is the FMC's estimate of the quality of its position determination. The FMC is 95% certain the the aircraft's actual position lies within a circle of radius ANP centred on the FMC position. Therefore the lower the ANP, the more confident the FMC is of its position estimate.

To be more correct, you should say the lower the ANP the smaller radii of position uncertainty.

The FMC is neither more or less confident, it is just the size of the uncertainty that changes.

[FlightPathOBN]

In context, I am sure it is fine...

[code0]

Thanks a lot for the information. 737.org helped a lot, so are all replies above!

To tell you bit of extra info about this, I was flying a simulator session from VCBI to VOTR and an ILS approach to RWY 27 @ VOTR. I had to do a Go Around so I made a TOGA and suddenly TRNB 0152.4z appeared in the ND confusing me.

I am studying B1, but trying to get the whole concept of flying so I could understand more things when the aircraft is flying as now I spend more time with the aircraft when it is on ground

Thanks to all!

[aterpster]

Pub User:

It could be the older Boeing system of using 'NB' after the name of an NDB. Is there a 'TR' NDB in your database?

Worldwide:

9 TR NDBs, 3 TR VORs.

[BOAC]

Originally Posted by Pub User

It could be the older Boeing system of using 'NB' after the name of an NDB. Is there a 'TR' NDB in your database?

- there certainly is if you look at the route page.

Code0 - here is your NDB at VOTR..

http://www.google.co.uk/url?sa=t&rct...maBP6kcHgDO-uQ

[code0]

@BOAC . . precisely! thanks a trillion for digging up!

[BOAC]

My pleasure - just had to stop this 'wandering around the houses' we have been watching Quite how we finished up in UKBB at an IF or Montserrat defeats me. I found at least 6 TR NDBs worldwide.

If you look up VOTR in the India AIP you will see the hold at TR. The g/a off 27 goes right to the TR to hold.

[FlightPathOBN]

The same question was posted on another Sim site...there is a TR NDB there as well, that was coded in the SIM database as an IF not TF leg, and it made sense with the image shown...
thats how!

[code0]

Thank you all! and thanks for the time for reading and replying!

Just a small question what is a TR NDB ? and TR VOR? . . . is it a special kind ?

Thanks in advance!

[BOAC]

code0 - if you look at the link I gave you will/?should? clearly see 'TR' is the ident.

I feel this thread should be in 'Spectators Balcony' We have no idea what level of piloting knowledge your 'B1' licence give you and I feel we are wasting our time here with someone who cannot use a search engine.

Exactly WHAT is your level of piloting knowledge?

[Torque Tonight]

If ever you were an instructor BOAC, I presume you would have specialised in the 'I can do it so why can't you' instructional technique. Whatever happened to sharing knowledge with encouragement and good grace. If you really feel that as you said, you are wasting your time, perhaps you shouldn't bother answering people's questions at all. Incidentally, that format for an NDB is certainly not common to all Boeing FMCs.

[BOAC]

You mean like up to post #17 when I realised what we were dealing with.? Doh! You would have been chopped.

You probably did not notice, either, but the last question was "Just a small question what is a TR NDB ? and TR VOR? . . . is it a special kind ?"

Can you work that out for yourself or do you need help?

[Torque Tonight]

Certainly some people here know less than others, but I don't think any of us know it all, even you , so perhaps a little friendly elucidation of information is no bad thing.