RNAV vectors

"Steven P. McNicoll" wrote in message
news

"Dan Luke" wrote in message
...

You cannot do anything like that on my KLN-90B without suspending
waypoint sequencing. That would seem to me to be a barrier to RNAV
vectoring to final for ATC, since the variability of equipment in this
respect cannot be accounted for.


That would seem to suggest there IS something special about vectoring to
final on GPS approaches.


It would seem to suggest no such thing. You seem to think that FAAO 7110.65
is only advisory and that the design approach taken by some equipment
manufacturer actually defines the rules you should use for vectoring
aircraft to approaches.

Perhaps you should become familiar with FAAO 7110.65 and the P/CG if you
want to know about vectoring to final on GPS approaches.

Steven P. McNicoll wrote:

"Dan Luke" wrote in message
...

You cannot do anything like that on my KLN-90B without suspending waypoint
sequencing. That would seem to me to be a barrier to RNAV vectoring to
final for ATC, since the variability of equipment in this respect cannot
be accounted for.



That would seem to suggest there IS something special about vectoring to
final on GPS approaches.


Yes, it is sufficiently special that a lot of controllers can't do it in
accordance with 5-9-1.

"Stan Prevost" wrote:

Any point on the final approach course. One of the 480 "DIRECT" modes
is to set a course to/from an the thing you are going "DIRECT" to.
It's one of the options along with "enter a holding pattern at that
point". You're prompted for the course.


Is that a universal feature on IFR approach GPS?

You cannot do anything like that on my KLN-90B without suspending
waypoint sequencing. That would seem to me to be a barrier to RNAV
vectoring to final for ATC, since the variability of equipment in this
respect cannot be accounted for.


Can you not use your GPS to navigate to intercept a specified course to a
fix, and track that course, without a line on a moving map?

Yes, but it would require a bit of a home-made procedure to do it and
complete the approach. Here's how I could do it:

o Load the approach in the Flight Plan page
o Select direct to the FAF
o Put the GPS in OBS mode
o Set the OBS on the GPS CDI to the final approach course
o Use the CDI to intercept off the vector
o Just before the FAF, switch the GPS back to Leg mode to enable
sequencing

Or without a CDI?

Not sure what you mean here. I'd have to have something to indicate when I
was intercepting the course.

Have you ever flown an NDB approach with an ADF?

Eh?

--
Dan
C172RG at BFM

"Dan Luke" wrote in message
...


You cannot do anything like that on my KLN-90B without suspending
waypoint sequencing. That would seem to me to be a barrier to RNAV
vectoring to final for ATC, since the variability of equipment in this
respect cannot be accounted for.


Can you not use your GPS to navigate to intercept a specified course to a
fix, and track that course, without a line on a moving map?

Yes, but it would require a bit of a home-made procedure to do it and
complete the approach. Here's how I could do it:

o Load the approach in the Flight Plan page
o Select direct to the FAF
o Put the GPS in OBS mode
o Set the OBS on the GPS CDI to the final approach course
o Use the CDI to intercept off the vector
o Just before the FAF, switch the GPS back to Leg mode to enable
sequencing


That is a good procedure. I wouldn't call it home-made, in the usual sense
of that term, it is a proper way to do it if your GPS doesn't allow setting
a course to/from a fix on a Direct-To in an approach procedure. It was
discussed earlier in this thread as one way, perhaps the most common way, to
do it with the Garmin 430/530 units. These units just provide another way
that doesn't disable autoseqencing.

Or without a CDI?

Not sure what you mean here. I'd have to have something to indicate when
I was intercepting the course.

Have you ever flown an NDB approach with an ADF?

Eh?

My point in both of those last comments is that a course can be intercepted
and tracked with just the Bearing To Fix information provided by the GPS.
That is how it is done with an ADF, except there we have a needle pointer
instead of a numeric readout. It is easier with GPS because you have actual
Track information also, making wind correction trivial. Just intercept the
course, then fly headings to keep TRK=BRG=DTK (DTK=Desired Track on some GPS
units). Bearing will tell you when you are intercepting the course and when
you are tracking it. I find that pilots who learned GPS with moving map
displays have trouble with this, those who learned to fly NDB/ADF don't.
Try flying with just the numbers screen, cover the map and CDI.

By the way, Dan, when looking back at my response to your earlier post, I
was unhappy with the apparent tone of my response. It didn't sound like I
wanted it to. My apologies.

"Stan Prevost" wrote:

You cannot do anything like that on my KLN-90B without suspending
waypoint sequencing. That would seem to me to be a barrier to RNAV
vectoring to final for ATC, since the variability of equipment in this
respect cannot be accounted for.


Can you not use your GPS to navigate to intercept a specified course to
a fix, and track that course, without a line on a moving map?

Yes, but it would require a bit of a home-made procedure to do it and
complete the approach. Here's how I could do it:

o Load the approach in the Flight Plan page
o Select direct to the FAF
o Put the GPS in OBS mode
o Set the OBS on the GPS CDI to the final approach course
o Use the CDI to intercept off the vector
o Just before the FAF, switch the GPS back to Leg mode to enable
sequencing


That is a good procedure. I wouldn't call it home-made, in the usual
sense of that term, it is a proper way to do it if your GPS doesn't allow
setting a course to/from a fix on a Direct-To in an approach procedure.
It was discussed earlier in this thread as one way, perhaps the most
common way, to do it with the Garmin 430/530 units. These units just
provide another way that doesn't disable autoseqencing.

Now that I think about it more, this is really not much different from the
procedure for doing a full RNAV approach with a course reversal.

[snip]

By the way, Dan, when looking back at my response to your earlier post, I
was unhappy with the apparent tone of my response. It didn't sound like I
wanted it to. My apologies.


No offense taken. Thanks for your responses.

--
Dan
C172RG at BFM

On Sun, 17 Dec 2006 12:33:04 GMT, "Steven P. McNicoll"
wrote:


"Dan Luke" wrote in message
...

Anybody ever get vectors to final for RNAV approaches?

Around here (Mobile. AL), I never hear it, although there are plenty of
ARNAVs with lower minimums than the VOR approaches at both airports. If
you ask ATC for one of the ARNAVs, they'll clear you to an IAF every time.

Is there something special about vectoring for ARNAVs?


What kind of RNAV approaches are you referring to? Stand alone GPS
approaches tend to be made so that vectoring doesn't provide an advantage.

And here I always though they were VOR offsets. Although I have to
admit it's been well over 10 years since I actually heard any one give
an RNAV off set. :-))
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Roger wrote:
On Sun, 17 Dec 2006 12:33:04 GMT, "Steven P. McNicoll"
wrote:


"Dan Luke" wrote in message
...

Anybody ever get vectors to final for RNAV approaches?

Around here (Mobile. AL), I never hear it, although there are plenty of
ARNAVs with lower minimums than the VOR approaches at both airports. If
you ask ATC for one of the ARNAVs, they'll clear you to an IAF every time.

Is there something special about vectoring for ARNAVs?


What kind of RNAV approaches are you referring to? Stand alone GPS
approaches tend to be made so that vectoring doesn't provide an advantage.


And here I always though they were VOR offsets. Although I have to
admit it's been well over 10 years since I actually heard any one give
an RNAV off set. :-))
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Offsets are a feature in TSO 145/146 (WAAS capable) sets. The smart
money will use a slight offset to fly a Victor Airway to greatly reduce
the opposite direction mid-air potential. Minor offsets are already
approved on the North Atlantic.

Offsets should not be used for instrument approach or departure procedures.

"Sam Spade" wrote in message
...
Roger wrote:


And here I always though they were VOR offsets. Although I have to
admit it's been well over 10 years since I actually heard any one give
an RNAV off set. :-))
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Offsets are a feature in TSO 145/146 (WAAS capable) sets. The smart money
will use a slight offset to fly a Victor Airway to greatly reduce the
opposite direction mid-air potential. Minor offsets are already approved
on the North Atlantic.

Offsets should not be used for instrument approach or departure
procedures.

I thought Roger was talking about radial/DME offsets like used in KNS80 and
other RNAV boxes to define RNAV waypoints.

But course offsets were a feature of my old Northstar M3 IFR GPS. Not
mandated by TSO back then, though. I noticed the course offsets in the
GNS430W while reading the manual and wondered why they appeared.

Hard to imagine the FAA mandating course offsets to avoid center-of-airway
conflicts, given the following:

§ 91.181 Course to be flown.
Unless otherwise authorized by ATC, no person may operate an aircraft within
controlled airspace under IFR except as follows:

(a) On a Federal airway, along the centerline of that airway.

(b) On any other route, along the direct course between the navigational
aids or fixes defining that route. However, this section does not prohibit
maneuvering the aircraft to pass well clear of other air traffic or the
maneuvering of the aircraft in VFR conditions to clear the intended flight
path both before and during climb or descent.

Sam Spade wrote:
Offsets are a feature in TSO 145/146 (WAAS capable) sets. The smart
money will use a slight offset to fly a Victor Airway to greatly reduce
the opposite direction mid-air potential. Minor offsets are already
approved on the North Atlantic.

The CNX-80 has offsets. I didn't realize they were required by the TSO.
The story I had heard was the CAP wanted offsets so they could fly box
search patterns, and Apollo put the feature in to close a big sale to them.

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

Roger wrote:

And here I always though they were VOR offsets. Although I have to
admit it's been well over 10 years since I actually heard any one give
an RNAV off set. :-))
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Offsets are a feature in TSO 145/146 (WAAS capable) sets. The smart money
will use a slight offset to fly a Victor Airway to greatly reduce the
opposite direction mid-air potential. Minor offsets are already approved
on the North Atlantic.

Offsets should not be used for instrument approach or departure
procedures.


I thought Roger was talking about radial/DME offsets like used in KNS80 and
other RNAV boxes to define RNAV waypoints.

But course offsets were a feature of my old Northstar M3 IFR GPS. Not
mandated by TSO back then, though. I noticed the course offsets in the
GNS430W while reading the manual and wondered why they appeared.

Hard to imagine the FAA mandating course offsets to avoid center-of-airway
conflicts, given the following:

§ 91.181 Course to be flown.
Unless otherwise authorized by ATC, no person may operate an aircraft within
controlled airspace under IFR except as follows:

(a) On a Federal airway, along the centerline of that airway.

(b) On any other route, along the direct course between the navigational
aids or fixes defining that route. However, this section does not prohibit
maneuvering the aircraft to pass well clear of other air traffic or the
maneuvering of the aircraft in VFR conditions to clear the intended flight
path both before and during climb or descent.


The essence of that regulation was written in the 1950s. Anyone flying
..10 n.m off centerline would not even be noticed. (608 feet).