RNAV Equipment

[Tolka]

Does anyone know the bottom line regarding RNAV equipment in Europe. I've tried reading various articles/documents but they can be confusing.

My aircraft is a UK registered C172SP with a Garmin 1000 and I have a JAA IR. Am I correct in thinking the following:

(a) I can fly BRNAV enroute
(b) I can fly BRNAV STARs and SIDs
(c) I cannot fly PRNAV STARs or SIDs unless I receive authorisation (as operator) from the authority of the country of registry of the aircraft. If this is the case what is involved in getting the authorisation. Is it feasible for a light aircraft?

Tolka

[IO540]

My aircraft is a UK registered C172SP with a Garmin 1000 and I have a JAA IR. Am I correct in thinking the following:

(a) I can fly BRNAV enroute

If your GPS installation is BRNAV approved. A new C172 with a G1000 ought to be but you never know :) See the GPS supplement in your POH.

(b) I can fly BRNAV STARs and SIDs

Exactly as above. For example, my installation is BRNAV approved but only enroute, not SIDs/STARs.

(c) I cannot fly PRNAV STARs or SIDs unless I receive authorisation (as operator) from the authority of the country of registry of the aircraft. If this is the case what is involved in getting the authorisation. Is it feasible for a light aircraft?

The jury is still out on the interpretation of TGL10 which is the JAA garbage on PRNAV, with one or two UK avionics outfits struggling to get their heads around this (a polite description) and the rest being unable to do anything. Yes it should be feasible but the goalposts are being moved around. PRNAV approvals seems to be a productive money making activity for avionics shops but anybody who wants this ought to make the approval an express contract condition :)

I've sent you a PM/email.

[Islander2]

The information you seek, together with a lot else of value on RNAV operations, can be found in the excellent publication by Vasa Babic of PPL/IR Europe entitled RNAV Training Manual. It's obtainable from the Flyer Shop (shop.flyer.co.uk) and I'd thoroughly recommend it.

Be aware though, that for privately-operated G-reg aeroplanes:

1) very, very few aeroplanes currently have an appropriately-worded AFM Supplement for the GPS permitting P-RNAV operations; and
2) even fewer of their pilots (if actually any at all) have the requisite Operator's Letter of Authorisation for P-RNAV operations as issued by the UK CAA.

[IO540]

PRNAV could become the killer threat to IFR GA, because most currently fully IFR planes cannot be approved under the present regime (or anybody's understanding of it). I went to a Eurocontrol nav workshop last year and nobody there could agree on what it was about.

In the USA this will not be an issue because the FAA would never do anything so barmy...

A while ago I spoke to a very senior NATS ATCO whose view was that PRNAV is a load of bollox. He said that any plane flying on GPS, especially on autopilot, will easily meet PRNAV lateral accuracy (which is obviously true) and the rest of the stuff is going to remain tactically radar managed for the foreseeable future. It seems to me that Europe has turned PRNAV into yet another job creation scheme, deliberately obfuscated to keep it that way.

There are a few airports in Europe with PRNAV SIDs/STARs but currently all of them have some non-PRNAV (either RNAV, which "merely" requires BRNAV IFR GPS approval, or conventional navaid-defined) SIDs/STARs. I am sure this is necessary for compatibility reasons because the majority of jets (counting exec jets in that) flying around the place are not PRNAV approved. If this changed, those airports would instantly become out of bounds.

However RNAV itself is becoming very common at bigger airports. These SIDs/STARs cannot be flown without BRNAV approval, though to be fair one cannot legally fly enroute above FL095 without that anyway... Just noticed that Prague LKPR has gone all RNAV except one procedure.

RNAV transitions is another one. Look at Austria LOWW; plenty of those. Some IFR BRNAV GPSs, my KLN94 included, don't have these in their database and according to Honeywell never will have. There are various work-arounds e.g. entering the waypoints (which curiously are in the database). I don't think any of the x30 Garmins have an issue with this.

Back to PRNAV, anybody doing a major avionics refit must make PRNAV approval a condition of the contract.

[mm_flynn]

As an aside there is a quite interesting article in December's AOPA US mag on RNP approaches (which I believe is American for P-RNAV) with an Alaskan approach threading (as in multiple turns to maintain terrain clearance) through what appears to be a river valley carved into the mountains!

[IO540]

The whole RNAV thing is a c0ckup because the lateral navigation performance figures were based on the old inertial nav, using which a 747 pilot might know his position within a few miles. Today, with GPS, the whole required nav performance thingy is moot because you could fly, in a spamcan, from here to Mongolia and then fly back with the two tracks within not many metres of each other :)

Today's INS (in modern jets) is also accurate enough (with DME or GPS fixups) for any practical purpose.

But it seemingly has not stopped a whole load of committees jumping on the RNP boat and drawing up loads of "standards" which are irrelevant to actual flying and just cause certification nightmares.

PRNAV could be extra nasty because ATC will potentially be able to instantly verify whether the airframe on their radar has PRNAV approval. They can't do this for BRNAV which is taken on trust. So anybody flying a PRNAV procedure might be taking on a bit of a risk, one day.