Graham wrote:
Why do any of these standards of GPS precision matter even one iota, given that pre-GPS all CAT was flying around in airways and other controlled airspace with a navigation precision far worse than even the most basic GPS could provide?
These are not standards of “GPS precision”. They are standards of total navigational performance (including pilot performance) no matter what navigation system you use. They are just as applicable to VOR/DME, DME/DME and INS navigation systems.
The reason it matters is that in what you call “pre-GPS” days, airways were designed with the accuracy of VOR/DME/NDB in mind. Today, in PBN airspace, airways are designed with PBN specifications in mind. An RNAV 1 airway will be much narrower than a RNAV 5 airway.
Even a €50 GPS from a camping shop is accurate to “RNAV0.1”. This stuff is mostly circularly defined, for regulatory job creation. It’s like saying that a CAS infringer has caused a “loss of separation” when you have added 5000ft to the Mode C altitude in his transponder return…
I did the Oyster PBN course too. The CAA basically disregarded it however because they didn’t know what it was. They were looking for some bizzare form of wording from the examiner…
An RNAV 1 airway will be much narrower than a RNAV 5 airway
Can you show an example?
I had the impression PBN TK is included in the CBIR TK Syllabus and QB from 2019 under radio navigation (062)
062-01 Basic Radar Principles
062-02 Radio Aids
062-03 Radar
062-04 Intentionally Left Blank
062-05 Area Navigation Systems RNAV/FMS
062-06 Global Navigation Satellite Systems
062-07 Performance-Based Navigation (PBN)
Or you still need an additional TK exam to go with the PBN practical element?
It should be there since August 2018. I learned the material but it wasn’t on my exam in July 2018. I’ve done 30 hours flight training and am doing the CBIR 10 hours starting next week which will include PBN training. I’m hoping the ATO will just sign me off or give me an in house test or something to get me over the TK hurdle.
So PBN is basically checking that one can look at a screen that shows where one is and use it to determine where one is?
I often think that the aviators of yesteryear, for whom navigation was frequently very challenging, would be completely baffled at the fact that we have such brilliant, simple tools at our disposal and yet we elect to over-complicate it to such a degree.
Peter wrote:
Even a €50 GPS from a camping shop is accurate to “RNAV0.1”. This stuff is mostly circularly defined, for regulatory job creation.
Peter, you are missing the point. PBN specifications are not about navigation equipment accuracy, although that plays a part. They are about total navigational accuracy, i.e. about the accuracy of the actual aircraft flight path in relation to the intended path taking into account such things as pilot performance and even database coding accuracy. Pilot performance depends on factors such as interpretation of navigation instruments, reaction time, ability to set up a correct wind correction, availability of flight director and autopilot etc. Also, although GPS is ubiquitous in light GA, that is not the case in heavy GA or the airlines. Lots of heavy aircraft are flying with no GPS using DME/DME or INS (or a combination).
To give an example, if you have DME/DME navigation equipment, you require a flight director or autopilot to fly RNAV 1. The reason is that the total error of the navigation equipment and the pilot performance will be too large when hand flown on raw data. On the other hand, if you have GPS you can hand fly because the navigation equipment is sufficiently more accurate than DME/DME so that you stay within the RNAV 1 limits even when hand flying.
Graham wrote:
Why do any of these standards of GPS precision matter even one iota, given that pre-GPS all CAT was flying around in airways and other controlled airspace with a navigation precision far worse than even the most basic GPS could provide?Separation.
A lot of these are still circular arguments, defining stuff in terms of other (arbitrary) definitions.
For anoraks, it’s a bit like saying the speed of light is the ratio of the permittivity of free space and the permeability of free space, so by tweaking one or both of these you can make light go faster than light 
Peter wrote:
A lot of these are still circular arguments, defining stuff in terms of other (arbitrary) definitions.
Please show me such a circular argument. Pick one of the “a lot”. I’m not aware of a single one.
The mistake some people make in this thread is believing that PBN
- is all about GPS
- is all about fix accuracy
when none of that is true.
Well the inverse of the square root of their product, but who’s counting!?
