Compulsory for pilots to check for RAIM

[peterh337]

RAIM has always been mandatory for GPS approaches.

Making it mandatory for RNAV SIDs/STARs is fairly logical.

Making it mandatory for all enroute would make GPS useless in practice, because one is pretty likely to get a RAIM outage on the RAIM predictor calculation. However, this is irrelevant because any half decent GPS picks up so many more satellites than required for a 3D fix that the RAIM prediction is not relevant to accuracy.

However a lot hangs on the way "primary" is defined. In reality, a pilot will use a mixture of nav sources enroute... you tune in a VOR, a DME if there is one colocated (rarely the case in France which is why I wonder how the hell anybody uses a KNS80 in France) or even an NDB if it is a waypoint (and many are on Eurocontrol routes) so the concept of "primary" goes out of the window.

It would also be quite a precedent to dictate what equipment should be used. Equipment carriage regs normally specify (private flight context) what equipment is to be carried which is totally different.

[IMCR]

Flyin"Dutch"

Sorry, link doesnt work for me.

G430/530 - Aux, RAIM prediction computes the prediction for the time of arrival but I dont think it deals with the en route segement.

[aberdeen_taffy]

Wouldn't suprise me however if you could select a waypoint on your flightplan in Aux to check RAIM when you are planning to be there. Can't remember doing it though, just the arrival.

[Flyin'Dutch']

Google it.

That is how I found it. It also tells you how to fullfill the requirement.

TERPS review from 1997 which also has some information about RAIM for approaches which confirms that this has been around for a bit for those.

[Keef]

Memory for details isn't my forte, but I remember checking forecast RAIM integrity before flying GPS Approach Trials. Not sure why, unless the practice briefing said to do so.

The 430 shouts soon enough if it's not happy with GPS coverage, or so I understand.

[IMCR]

NOTE: Until June 30, 2009, a RAIM prediction does not need to be done for any RNAV route conducted where ATC provides radar monitoring or RNAV departure/arrival procedure that has an associated "RADAR REQUIRED" note charted. On July 1, 2009, operators filing RNAV 1 routes (Q and T), RNAV 1 STARs, and RNAV 1 DP’s will need to perform a RAIM prediction as part of their preflight planning.

Link now works, but I think the earlier post stands of June 2009 in the context I referred.

I agree Peter.

Yep, you appear to be able to check a waypoint but only if the waypoint is your final destination and in any event that would not verify the en route segement I guess unless that was made up of an infinite number of waypoints.

[Flyin'Dutch']

Flyin"Dutch"

Sorry, link doesnt work for me.

G430/530 - Aux, RAIM prediction computes the prediction for the time of arrival but I dont think it deals with the en route segement.

Just checked link and pukka from here.

But this is the article's title so Google that and all shall become clear:

Operation on U.S. Area Navigation (RNAV) Routes,
Standard Terminal Arrivals, and Departure Procedures

[denhamflyer]

For those that need an easy way to check RAIM, plus checkout the help page wrt when it is needed under the JAA

http://augur.ecacnav.com/augur/app/home

[mancpilot]

When I say to the 1800WXBRIEF pre-flight briefer "DA42 slant Golf" he knows it has an IFR certified GPS and now says "would you like a RAIM check".....

"No, I'd like it now please!"

Mancpilot

[KNT754G]

Memory for details isn't my forte, but I remember checking forecast RAIM integrity before flying GPS Approach Trials. Not sure why, unless the practice briefing said to do so.

It was a requirement for the trial.

Any IFR certified GPS unit (especially an IFR Approach certified unit) will be able to do a RAIM check.

[Frank Leopald]

For chaps and chapesses who fly over Blighty, may I recommend CAP 773? It's a right riveting read and gives good advice about the range of checks one should complete when contemplating GPS Nav.

'course one could be cheeky and ask the 2 UK aerodromes what have NPA's in space, if they have any NANU's?

Frank Leopald

[peterh337]

Hmmm, now where is the 1000 page document explaining the pitfalls of the ADF?

[bookworm]

RAIM has always been mandatory for GPS approaches.

Making it mandatory for RNAV SIDs/STARs is fairly logical.

Making it mandatory for all enroute would make GPS useless in practice, because one is pretty likely to get a RAIM outage on the RAIM predictor calculation.

RAIM has always been required to meet European BRNAV requirements. The reason it tends to get forgotten is that for years the number of satellites available has meant that the enroute requirement (2 nm tolerance) is always satisfied, without reference to geography or time.

The more demanding requirements of terminal(1 nm)/approach(0.3 nm) RAIM are rarely/occasionally (respectively) unmet.

[Keef]

But as Peter so succinctly puts it, where's the RAIM for NDB?

In the USA, you have to have the NDB ident beeping in your ears the whole way round the procedure, and break off if the ident goes away. I don't think the CAA or EASA even has that simple integrity check.

[421C]

Many of the topics in this thread are covered in pages 123-128 of this document
http://www.pplir.org/images/stories/ppl ... ual1_8.pdf

On the US "RNAV 1", see pages 7,8 & 32. RNAV 1is the US equivalent of P-RNAV.

brgds
421C