What kind of equipment can be used to meet RNP .3? I'm aware of GPS
and DME/DME.

Greg Esres wrote:

> What kind of equipment can be used to meet RNP .3? I'm aware of GPS
> and DME/DME.

Only GPS with either selectable scaling to 0.3, flight director, or
autoflight coupled to RNAV. DME/DME is not authorized RNP 0.3 except
with special authorization at some locations.

<<Only GPS with either selectable scaling to 0.3, flight director, or
autoflight coupled to RNAV. DME/DME is not authorized RNP 0.3 except
with special authorization at some locations.>>

Thank you. In regards to the last, the instrument approach plates
that do not allow RNP 0.3 say "Not Authorized". I assme that every
plate without that IS authorized. Are you saying that the latter is
"special authorization" ?

Greg Esres wrote:

> <<Only GPS with either selectable scaling to 0.3, flight director, or
> autoflight coupled to RNAV. DME/DME is not authorized RNP 0.3 except
> with special authorization at some locations.>>
>
> Thank you. In regards to the last, the instrument approach plates
> that do not allow RNP 0.3 say "Not Authorized". I assme that every
> plate without that IS authorized. Are you saying that the latter is
> "special authorization" ?

So far as I know, they all say:

"GPS or RNP 0.3 required. DME/DME RNP 0.3 NA."

And, the first sentence has a bit of "The Emperor has no clothes" in it,
in that it suggests there is some way of getting to RNP 0.3 in addition
to GPS. That comes from the sensor-independent concept of RNP. Trouble
is there is no sensor other than GPS around today that will do RNP 0.3.

<<"GPS or RNP 0.3 required. DME/DME RNP 0.3 NA.">>

I thought I had found a number without that notation, but, those may
have been "GPS" approaches, rather than RNAV.

<<And, the first sentence has a bit of "The Emperor has no clothes" in
it, in that it suggests there is some way of getting to RNP 0.3 in
addition to GPS. That comes from the sensor-independent concept of
RNP. Trouble is there is no sensor other than GPS around today that
will do RNP 0.3.>>

That sort of discrepancy is why I'm having such a hard time preparing
a sheet that clearly describes each type of GPS-based approach and
what equipment is required to fly it.

There seems to be a lot of hand-waving going on when the FAA (or
anybody else) talks about these things. Does anyone fully understand
what's going on?

Greg Esres wrote:

> <<"GPS or RNP 0.3 required. DME/DME RNP 0.3 NA.">>
>
> I thought I had found a number without that notation, but, those may
> have been "GPS" approaches, rather than RNAV.

If it says "GPS" rather than "RNAV (GPS)" it very well may have no note at
all. But, since most of the legacy LNAV suites are in Part 121
operations, those approaches aren't approved under op specs in any case.

>
>
> <<And, the first sentence has a bit of "The Emperor has no clothes" in
> it, in that it suggests there is some way of getting to RNP 0.3 in
> addition to GPS. That comes from the sensor-independent concept of
> RNP. Trouble is there is no sensor other than GPS around today that
> will do RNP 0.3.>>
>
> That sort of discrepancy is why I'm having such a hard time preparing
> a sheet that clearly describes each type of GPS-based approach and
> what equipment is required to fly it.
>
> There seems to be a lot of hand-waving going on when the FAA (or
> anybody else) talks about these things. Does anyone fully understand
> what's going on?

Nope. Too many snake oil salemen stirring the soup.