RNAV vectors

Steven P. McNicoll wrote:
"Roy Smith" wrote in message
...

Sure. And what's so cool about the internet today is that not only can I
show you the chart for the approach
(http://204.108.4.16/d-tpp/0612/00286VDG24.PDF), I can also show you how
we
flew it
(http://flightaware.com/live/flight/N...953Z/KHPN/KPOU)
. Now all we need are the ATC tapes and a webcam sitting on the pilot's
shoulder :-)

On the other hand, I'm not sure if a "... or GPS ..." approach is quite
the
same thing as a "RNAV GPS ..." approach.



No, RNAV approaches have RNAV in the name.



A lot of the older ones have just "GPS" (as opposed to "or GPS). The
ones that say "GPS Runway 8" (for example) are RNAV IAPs.

"Steven P. McNicoll" wrote in message
k.net...


There is something special about vectoring to final on GPS approaches,
though. Unlike localizers or VOR radials, a GPS FAC has a definite "end".
The course does not extend beyond what's charted so there's nothing to
intercept.


From the P/CG:

==================

FINAL APPROACH COURSE- A bearing/radial/track of an instrument approach
leading to a runway or an extended runway centerline all without regard to
distance.

COURSE-

a. The intended direction of flight in the horizontal plane measured in
degrees from north.

b. The ILS localizer signal pattern usually specified as the front course or
the back course.

c. The intended track along a straight, curved, or segmented MLS path.

==================

Final Approach Course is not the same as Final Approach Segment.

"Stan Prevost" wrote in message
...

From the P/CG:

==================

FINAL APPROACH COURSE- A bearing/radial/track of an instrument approach
leading to a runway or an extended runway centerline all without regard to
distance.

COURSE-

a. The intended direction of flight in the horizontal plane measured in
degrees from north.

b. The ILS localizer signal pattern usually specified as the front course
or the back course.

c. The intended track along a straight, curved, or segmented MLS path.

==================

Final Approach Course is not the same as Final Approach Segment.


You've missed the point.

Let's look at a couple of approaches at Titletown to illustrate. First, the
ILS RWY 36:

http://map.aeroplanner.com/plates/Fa.../00873IL36.PDF

An aircraft is inbound from O'Hare, on initial contact it's instructed to
turn ten degrees left and join the runway 36 localizer. It intercepts about
thirty miles from the field and tracks inbound. No problem.

Now look at the RNAV RWY 36 approach:

http://map.aeroplanner.com/plates/Fa...s/00873R36.PDF

Same situation, an aircraft is inbound from O'Hare, on initial contact it's
instructed to turn ten degrees left and join the final approach course for
the RNAV RWY 36. It crosses the extended final about thirty miles south of
the field and continues on it's heading. There's nothing for it to
intercept, nothing similar to a localizer that it can join.

"Steven P. McNicoll" wrote in message
.net...

"Stan Prevost" wrote in message
...

From the P/CG:

==================

FINAL APPROACH COURSE- A bearing/radial/track of an instrument approach
leading to a runway or an extended runway centerline all without regard
to
distance.

COURSE-

a. The intended direction of flight in the horizontal plane measured in
degrees from north.

b. The ILS localizer signal pattern usually specified as the front course
or the back course.

c. The intended track along a straight, curved, or segmented MLS path.

==================

Final Approach Course is not the same as Final Approach Segment.


You've missed the point.

Let's look at a couple of approaches at Titletown to illustrate. First,
the ILS RWY 36:

http://map.aeroplanner.com/plates/Fa.../00873IL36.PDF

An aircraft is inbound from O'Hare, on initial contact it's instructed to
turn ten degrees left and join the runway 36 localizer. It intercepts
about thirty miles from the field and tracks inbound. No problem.

Now look at the RNAV RWY 36 approach:

http://map.aeroplanner.com/plates/Fa...s/00873R36.PDF

Same situation, an aircraft is inbound from O'Hare, on initial contact
it's instructed to turn ten degrees left and join the final approach
course for the RNAV RWY 36. It crosses the extended final about thirty
miles south of the field and continues on it's heading. There's nothing
for it to intercept, nothing similar to a localizer that it can join.


Of course there is something to intercept. There is the final approach
course. By definition, it extends southward from the runway on a course of
182 degrees forever, to SENNA and beyond.

RNAV/GPS equipment does not need a navaid signal overlying the FAC to allow
me to navigate it. I can intercept and track that FAC with my GNS430 GPS,
and it will even draw a magenta line for me on the map.

However, I don't see any advantage to such vectors over a clearance direct
SENNA. And if the MVA is higher than 2500, there can be a disadvantage.

Steven P. McNicoll wrote:


http://map.aeroplanner.com/plates/Fa...s/00873R36.PDF

Same situation, an aircraft is inbound from O'Hare, on initial contact it's
instructed to turn ten degrees left and join the final approach course for
the RNAV RWY 36. It crosses the extended final about thirty miles south of
the field and continues on it's heading. There's nothing for it to
intercept, nothing similar to a localizer that it can join.



The pilot can go to OBS mode and select FRZZN as the active waypoint,
then select bearing 002 mag to FRZZN.

The controller would have to issue a crossing altitude at SNENNA
consistent with the IAP. 7110.65P 5-9-4 and, specifically, Example #4.

"Sam Spade" wrote in message
...


The pilot can go to OBS mode and select FRZZN as the active waypoint, then
select bearing 002 mag to FRZZN.


You don't have to use OBS mode, at least on the GNS430. Use DIRECT TO, then
set the course. This way draws a line on the map, OBS doesn't.

"Stan Prevost" wrote in message
...

Of course there is something to intercept. There is the final approach
course. By definition, it extends southward from the runway on a course
of 182 degrees forever, to SENNA and beyond.

RNAV/GPS equipment does not need a navaid signal overlying the FAC to
allow me to navigate it. I can intercept and track that FAC with my
GNS430 GPS, and it will even draw a magenta line for me on the map.


You're mistaken.

Stan Prevost wrote:

"Sam Spade" wrote in message
...

The pilot can go to OBS mode and select FRZZN as the active waypoint, then
select bearing 002 mag to FRZZN.



You don't have to use OBS mode, at least on the GNS430. Use DIRECT TO, then
set the course. This way draws a line on the map, OBS doesn't.



That won't work with the GNS400/500 series. Doing it the way I describe
will provide a course line. I don't have a clue about the 480. ;-)

"Stan Prevost" wrote in message
...

You don't have to use OBS mode, at least on the GNS430.

That would imply that there are variations in the way different model GPS
receivers perform.



Use DIRECT TO, then set the course. This way draws a line on the map, OBS
doesn't.


DIRECT TO where? The clearance was to turn ten degrees and join the final
approach course.

"Sam Spade" wrote in message
...
Stan Prevost wrote:

"Sam Spade" wrote in message
...

The pilot can go to OBS mode and select FRZZN as the active waypoint,
then select bearing 002 mag to FRZZN.



You don't have to use OBS mode, at least on the GNS430. Use DIRECT TO,
then set the course. This way draws a line on the map, OBS doesn't.



That won't work with the GNS400/500 series. Doing it the way I describe
will provide a course line. I don't have a clue about the 480. ;-)

Works on my 430s, and works on the 430 simulator/trainer. But on the sim, I
also got the magenta line using OBS mode, didn't think I could. Don't
remember what caused me to believe that.