747-400 Prnav

[Torquelink]

I have an interest in a number of 744s but am not flight deck or technical so please forgive my ignorance.
Some of these aircraft have triple IRS but no GPS installed: can they be PRNAV compliant in this configuration? Or are there different levels of PRNAV accuracy, the lower of which they might meet? The other aircraft have triple IRS and twin GPS so I assume that they will / could be compliant. All these aircraft are presently flying schedules into / out of Europe and I'd like to know whether they will continue to be able to do so or whether they will require modified nav sytems at some point?
Many thaanks
Torque

[theearl]

Correct me if i am wrong but for prnav or RNP1 all you need is for FM update is 1x vor or gps and 1 x dme or gps. Remember Prnav is only sid/stars.

Hope this helps

[alatnariver]

Here you will find a lot of info re. P-RNAV:
http://www.ecacnav.com/content.asp?CatID=22
Just look throug it. A good compilation of Q&A's can be found here, from the same site: http://www.ecacnav.com/downloads/P-RNAV09-05.pdf

[Torquelink]

Thanks for these responses - especially the ecac website reference. Seems to me that, as theearl says, the combination of VOR/DME gets you there anyway plus, of course, these aircraft have IRS. It would seem to be a reasonable assumption that all these aircraft meet RNP-1 with their existing avionic fits as, I assume, European controlled airspace requires RNP-1 as a minimum.

Cheers

[dusk2dawn]

A "reasonable assumption" is not enough. You have to document that the equipment complies with and is certified to the required RNP.

[Tight Slot]

well we need RNP of at least .3 miles to do a GNSS RNAV apprch. Works very well, like an ILS down to around 600 ft... 2 GPS, 3 Adirs etc on the 330

[Torquelink]

Dusk, we're asking the operator for confirmation but my assumption is based on the fact that the aircraft are operating to / from major European airports at present - can you confirm that that means they must have at least RNP 1?

Cheers

[dusk2dawn]

No, I believe it is RPN5 all over EU (except for some obscure dep/arr procedure here and there....)
However, check:

• ICAO Doc 7030 Regional Supplementary Procedures (EUR RAC).
• Eurocontrol on required equipment

[Torquelink]

Thanks Dusk. CAA also confirm its RNP5 pretty much everywhere although likely to get tightened at some unspecified time. I've also confirmed that all our aircraft are RNP5 certificated too - regardless of whether they have GPS or not.

Cheers