All-PRNAV airports

[bookworm]

They might be BRNAV approved but they definitely won't be PRNAV approved.

You should come to more PPL/IR Europe meetings, IO540. Weren't you at Cambridge when Paul and Anthony explained how they got the PRNAV certification?

By the way, PRNAV is (more or less) RNAV1, not RNP1. There is no requirement for on-board performance monitoring and alerting.

[FlyingForFun]

They are approved for non-precision RNav approaches. All of the CAA Staff Examiners at Bournemouth have flown RNav approaches in our aircraft after having inspected the approval.

Surely the approval for approaches (RNP0.3) will also cover PRNav (RNP1.0)? I'm not 100% on that, because we don't fly any PRNav procedures, but not only does it logically make sense, it's also implied in CAP773:

a system that meets the PRNAV certification (flying in the terminal area on RNAV SIDs and STARs) is required to be accurate to within 1 NM for 95% of the time, however, this still does not meet the required navigation performance for use in NPA operations

(Therefore, by implication, a system which does meet the required navigation performance for use in NPA operations, such as ours, also meets the requires for PRNav?)

If that's not right, I'd be very curious as to why it's not right. I'm still fairly new to all of this, I've just about managed to get my head around the terminology used in the various types of RNav approaches, but I don't have any experience of RNav departures/arrivals, etc, and I'm ready to learn if my assumptions are wrong.

FFF
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[IO540]

They are approved for non-precision RNav approaches.

OK, now it makes sense.

Your FTO has got its fleet approved to fly GPS/RNAV approaches

That is an EASA Minor mod - easy. The procedure is similar to BRNAV and has similar equipment (annunciator location, etc) requirements to BRNAV. Similar tests for VHF interference, etc.

Surely the approval for approaches (RNP0.3) will also cover PRNav (RNP1.0)?

That kind of progressive thinking will never get you a job at Eurocontrol. As you have just discovered, this king has no clothes, and has not even had a pair of pink underpants for more than a decade.

Of course PRNAV is total bollox, when you can get a GPS approach approval.

But you must be a good citizen and think of all those poor failed ISO9000 quality managers who are pushing PRNAV. They have families to feed.

As regards a serious answer, I think it is in several parts. Your GPS needs an LOA from the mfg and not all IFR GPSs (all of which are OK for a GPS approach approval) have this LOA. Then, under EASA, it is a Major mod (4 figures). It is an AFMS under the FAA which is also a Major mod, done with a 337, but the FAA has a straight process for flight manual supplements (well, in the USA, anyway...).

N-regs also need an EHSI for PRNAV, if doing it today. G-regs don't.

You should come to more PPL/IR Europe meetings, IO540. Weren't you at Cambridge when Paul and Anthony explained how they got the PRNAV certification?

That's two planes. I haven't been to the meetings for a few years.

I gather from someone in the business that they got in before the EASA clampdown. Last year a friend had a major (£30k?) avionics job done, with PRNAV paperwork, but the allegedly promised paperwork never turned up, and the last I heard from him was that he was still waiting for it but then he died - around middle of 2010.

So there are probably just two in Europe; maybe a few more around. I know loads of European IFR pilots and none of those I know appear to have the masochistic tendencies required to do this now.

It used to be quite doable on the N-reg, before the NY IFU washed its hands of avionics 337s. We both know one chap who got his plane done, in the very early days before anybody knew what this was about, by burying the FSDO under so much paper they rubber stamped it all just to be able to breathe again. Now, you have to use a "different route"...

The basic point however is that it is irrelevant to IFR flight. It's a pure job/activity creation scheme.

[bookworm]

Surely the approval for approaches (RNP0.3) will also cover PRNav (RNP1.0)? I'm not 100% on that, because we don't fly any PRNav procedures, but not only does it logically make sense

You're not the only one to use the word "logical" in that context -- so does ICAO in its PBN manual. Unfortunately...

1.2.5.3 Understanding RNAV and RNP designations
1.2.5.3.1 In cases where navigation accuracy is used as part of the designation of a navigation specification, it should be noted that navigation accuracy is only one of the many performance requirements included in a navigation specification — see Example 1.

1.2.5.3.2 Because specific performance requirements are defined for each navigation specification, an aircraft approved for an RNP specification is not automatically approved for all RNAV specifications. Similarly, an aircraft approved for an RNP or RNAV specification having a stringent accuracy requirement (e.g. RNP 0.3 specification) is not automatically approved for a navigation specification having a less stringent accuracy requirement (e.g. RNP 4).

1.2.5.3.3 It may seem logical, for example, that an aircraft approved for Basic-RNP 1 be automatically approved for RNP 4; however, this is not the case. Aircraft approved to the more stringent accuracy requirements may not necessarily meet some of the functional requirements of the navigation specification having a less stringent accuracy requirement.

[Jan Olieslagers]

The whole discussion is unlikely to be relevant for me, seeing I fly microlights that are generally supposed to stay clear of controlled airspace. Still, out of sheer curiosity: what is al this BRNAV and PRNAV and what not?

[bookworm]

That's two planes. I haven't been to the meetings for a few years.

It was a small fleet of aircraft, in fact. But the point is that it was the [i]same[i/] fleet of aircraft, the Duchesses and Sierra, that FFF flies, about which you said:

They might be BRNAV approved but they definitely won't be PRNAV approved.

Overall, I'm not disputing your point. Obtaining PRNAV approval is pointlessly, and therefore dangerously, difficult.

[FlyingForFun]

Right, I think I've got it:

- Approval for RNav approaches does not automatically include approval for PRNav
- Approval for BRNav and for RNav approaches is quite easy to get
- Approval for PRNav is more difficult to get, for no real reason except beaurocracy
- IO540 assumed, because my aircraft aren't jets, that they're not PRNav-approved
- Bookworm has attended a talk by my boss, and, based on what was said at that talk, believes my aircraft are PRNav-approved

Now that I'm at work, I've been able to dig out a couple of the certificates. In fact, IO540 and Bookworm are both only partly correct - of the first two certificates I looked at, one aircraft is PRNav-approved, and the other isn't! I'm not sure about the other two Duchesses, I'll have a look at their paperwork later.

Thanks! All is now clear as mud!

FFF
-----------

(PS - Jan, I started typing a reply to your question then lost it by mistake, haven't got time to re-type it now. I'll answer it later if no one else gets in first.)

[IO540]

Indeed it would totally amaze me if a UK FTO pushed its piston fleet through PRNAV approval, at a cost of perhaps £5k-10k per aircraft, for the paperwork (totally irrelevant for any IR training purposes, anywhere in Europe AFAICT) but a zero functional improvement.

OTOH if doing a significant avionics refit anyway, only a fool would not absolutely insist on less than PRNAV. And very very few UK shops can actually deliver that at present.

Aircraft approved to the more stringent accuracy requirements may not necessarily meet some of the functional requirements of the navigation specification having a less stringent accuracy requirement.

I don't know what they are talking about. If they mandated an EHSI (enabling a multi waypoint route to be flown hands-off, with the course pointer always showing the current track, thus ruling out a mechanical HSI with GPSS retrofitted, because the CP on that does not move, compromising situational awareness) then it would make some sense. But they don't.

and therefore dangerously, difficult.

"Dangerous" assumes operational relevance, no?

I'd say that a Major mod requirement for TAWS would be dangerous. (it probably is, but EASA/Eurocontrol are nothing to do with aviation; it's just a nice retirement number for failed ISO9000 quality managers and other assorted control freaks).

Right, I think I've got it:

- Approval for RNav approaches does not automatically include approval for PRNav

Yes.

- Approval for BRNav and for RNav approaches is quite easy to get

Yes, generally. Subject to VHF-GPS interference checks - see AC 20-138A or a similar EU spec (which I have as a PDF but the URL is now dead).

- Approval for PRNav is more difficult to get, for no real reason except beaurocracy

Yes.

- IO540 assumed, because my aircraft aren't jets, that they're not PRNav-approved
- Bookworm has attended a talk by my boss, and, based on what was said at that talk, believes my aircraft are PRNav-approved

Now that I'm at work, I've been able to dig out a couple of the certificates. In fact, IO540 and Bookworm are both only partly correct - of the first two certificates I looked at, one aircraft is PRNav-approved, and the other isn't! I'm not sure about the other two Duchesses, I'll have a look at their paperwork later.

Amazing. I wonder why any FTO would bother at all.

[SNS3Guppy]

RNAV is OK. I don't have an issue with that, because as I said RNAV is de facto necessary just to fly in the IFR enroute system.

That's definitely not the case. GPS, RNAV, and little magenta lines aren't necessary to operate in the enroute environment. They're nice toys, but they definitely aren't necessary.

[IO540]

That's definitely not the case. GPS, RNAV, and little magenta lines aren't necessary to operate in the enroute environment. They're nice toys, but they definitely aren't necessary.

One day, Guppy, we will all work out which part of the known universe you fly in, IFR, enroute, Eurocontrol airspace.

It's not Europe, for sure.

Without BRNAV you are illegal anyway, in any practical flight. Personally I wouldn't write about doing it, just in case you get rumbled one day.

[SNS3Guppy]

It's illegal to fly using a VOR on an airway from A to B in Europe?

It's certainly not that way throughout the rest of the world. Perhaps if you'd suggested that one can't fly without RNAV in your small corner of the world, you'd have been more accurate.

Imagine, the ability to move from A to B without a magenta line. How fantastic and mystical that must seem to you.

[IO540]

1) On a private flight (i.e. non-AOC, so there is no company procedures manual approved by the national CAA) you are allowed to use any means of navigation you wish, including the proverbial tuna sandwich

2) In Euro airspace, the carriage of a BRNAV approved navigation receiver is mandatory. In the context of currently manufactured civilian avionics this can be met only with a) INS or b) an IFR GPS.

3) ATC watch you like a hawk and expect precision performance. When they say "DCT XYZ" and 20 seconds later you are still pointing 10 degrees away, they are onto you, even though at that point your lateral track error is probably only a mile or two. Evidently they watch the computer-extrapolated track...

So, in Europe, "total RNAV" is a done deal and the only question is whether you are doing it with an FMS (with DME/DME or GPS corrections) or directly with a GPS. It's obviously very easy and effortless to fly this way.

If you lose RNAV capability you need to advise ATC, and they will either give you vectors, or give you some VOR-able route.

BRNAV does not (currently) apply below FL095, but if you want to see the feasibility of developing valid routes around Eurocontrol-land below FL095, download a copy of this and have a little play, setting the max level to FL095, and see how far you get before you run out of juice Actually it works in some places, like France.

PRNAV is something else....

[SNS3Guppy]

How exactly does one navigate with a tuna sandwich?

[Final 3 Greens]

He didn't say you can navigate with a Tuna sandwich, he said you are allowed allowed to.

Any fool knows that a smoked salmon bagel is the navtool of choice.

[IO540]

The key is that in the private flight context

equipment required to be carried

is not the same as

equipment actually used

So it is legal to navigate with a smoked salmon roll (I agree BTW, though parma ham is even better) but you have to carry a BRNAV approved GPS.

No kidding.

[SNS3Guppy]

I believe both the Tuna and the Smoked Salmon Bagle methods are only appropriate for water routes, or routes within 150 nautical miles of a bona fide salt water body.

Christie Brinkley doesn't count.

[bookworm]

Indeed it would totally amaze me if a UK FTO pushed its piston fleet through PRNAV approval, at a cost of perhaps £5k-10k per aircraft, for the paperwork (totally irrelevant for any IR training purposes, anywhere in Europe AFAICT) but a zero functional improvement.

The paperwork cost was in this case quite low, because the approval was sought in conjunction with GPS approach approval. It was a single mod at the time. From memory, it was nothing like as high as the costs you mention.

"Dangerous" assumes operational relevance, no?

No it just assumes that money, concentration and time spent on pointless certification could be spent on something that makes a genuine difference to safety instead.

[IO540]

I recall a post by a well known avionics shop man saying that the PPL/IR examples got in as a minor mod but that EASA have within the past few months blocked that route.

A pure RNAV approach approval remains an EASA minor mod.

(FWIW, on an N-reg I don't know of a way of getting the 337+AFMS approved. I have some contacts but nothing concrete. It's probably done by submitting the papers to a US FSDO via a contact in the USA).

I agree regarding the safety angle, of course. But I don't see any evidence that EASA policy runs on safety. Everything I see is driven by blatent in-your-face work creation. It may just be a coincidence that work creation and safety go hand in hand but why is the work creation angle always so obvious while the safety angle remains so non-transparent?

[421C]

FWIW, on an N-reg I don't know of a way of getting the 337+AFMS approved. I have some contacts but nothing concrete. It's probably done by submitting the papers to a US FSDO via a contact in the USA

This is a problem for IFR approval in general for the N-reg (where you do need a 337) but not for PRNAV where there is an existing IFR approved GPS and it is PRNAV compliant. You do not have to have a Flight Manual Supplement, TGL10 permits a compliance statement. Therefore it is just a matter of documenting TGL10 compliance (iaw AC90-96A) and applying to the NY IFO for an LoA. I am not aware of this requirement for an EHSI - where did this come from?

[IO540]

You do not have to have a Flight Manual Supplement, TGL10 permits a compliance statement.

Doesn't TGL10 apply only to EU-regs?

Interesting... obviously one needs a Garmin x30/W or similar to get the LoA.

I am not aware of this requirement for an EHSI - where did this come from?

Travis posted it.

I never found any mention of it in the US "pilot hangouts" but then I wouldn't because the FAA grandfathered all N-regs with an IFR GPS to PRNAV compliance, in US airspace, and 99.x% of US private pilots never leave US airspace especially for anywhere where anybody knows what PRNAV is.